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We demonstrate 100-Gbaud on-off-keying (OOK) transmission driven at a low voltage using an electro-optic (EO) polymer modulator combined with a silicon Mach-Zehnder interferometer waveguide. Various types of organic- and polymer-based modulators have been reported to perform efficient EO modulation and high-speed data transmission at over 100 Gbaud. However, there are critical concerns regarding the practical application of polymer devices in terms of environmental stability. In particular, long-term thermal storage and stability during operation require improvements before EO polymer modulators can be applied in practical systems. We have developed an EO polymer with enhanced thermophysical stability and used it to fabricate an efficient EO polymer modulator. In this study we extend our earlier work on high-speed EO polymer modulators by performing fiber-link 100-Gbaud OOK transmission at various operating temperatures. A thermal stability test revealed that the EO polymer modulator can survive high-temperature exposure up to 110°C. Error-free signal transmissions over a distance of 2.0 km was successfully demonstrated with a driving voltage of 1.9 Vpp and a bit error rate below the 7% overhead forward error correction threshold. The driving voltage, bandwidth, bit error rate, and fiber-link performance of the device are presented.

An 800-MHz OOK transmitter for short-range Internet-of-Things (IoT) applications is presented in this letter. The OOK transmitter utilizes a microelectromechanical system (MEMS)-based RF oscillator for carrier frequency generation, leading to a hardware- and power-efficient architecture. The transmitter is implemented in a 180-nm CMOS process and delivers −12.4-dBm output power. The power consumption of the MEMS oscillator is only 0.24-mW with 126.3-dBc/Hz phase noise at 100-kHz offset and a figure-of-merit (FoM) of 210.5 dB due to the optimized high- $Q$ aluminum nitride (AlN) piezoelectric MEMS resonator. The transmitter can provide a 120-Mb/s data rate of OOK modulation with an energy efficiency of 5 pJ/bit by directly switching ON/OFF the power amplifier (PA). The 175-ns startup time of the MEMS-based oscillator can support very heavy duty-cycle transmitter operation, leading to ultralow average power consumption of 50 nW.

The energy efficiency of an inductive wireless power transfer (WPT) system will deviate from the possible peak value if the magnetic coupling of the transmitter and receiver coils or the load resistance changes. To achieve maximum-efficiency tracking regardless of coupling or load changes, on – off keying (OOK) modulation is used. However it has the issue of large surge current in the circuits during OOK modulation. The current overshoots of a series–series (SS) compensated WPT system at the startup stage might be much higher than the rated current. The current overshoots not only increase the stress on the power switch devices but also cause high voltage spikes across the windings and the resonant capacitors which is a challenge for insulation design. A soft-start scheme is proposed to address the current overshoot problem. The principle of the soft-start scheme can be essentially applied to WPT systems with different compensation topologies. The experimental results of a 3.3-kW prototype verify that the proposed soft-start scheme effectively suppress the current overshoots.

A comprehensive study on the optical characteristics and high-speed transmission performance of a hexagonally arrayed seven-core fiber supporting both multimode transmission at 850 nm and quasi-single mode transmission at 1310 and 1550 nm are presented. We investigated its optical and transmission characteristics such as inter-crosstalk, modal bandwidth, chromatic dispersion, and misalignment tolerance. The results show that the multicore fiber (MCF) has a high bandwidth at 850 nm while remaining a comparable performance with standard single-mode fiber (SSMF) at 1310 and 1550 nm. The worst inter-core crosstalk is less than −43 dB over a 10 km-long MCF connected with a pairwise fan-in/fan-out devices. The minimum effective modal bandwidth of 8.44 GHz $\cdot$ km is achieved with the MCF for multimode operation, while the chromatic dispersion of the MCF at 1550 nm only increases by 7% compared with that of SSMF. In experiment, we successfully performed the 7 × 25 Gb/s multimode transmission over a 300 meter-long MCF at 850 nm and quasi-single mode transmission over a 12.4 and 10 km-long fiber at 1310 and 1550 nm, respectively, with an OOK modulation format. There was no obvious degradation observed when all cores operated simultaneously. Moreover, we carried out 7 × 50 Gb/s PAM4 transmission over a 300 meter-long and 10 km-long MCF at 850 and 1310 nm, respectively, as well as 7 × 40 Gb/s PAM4 transmission over a 10 km-long MCF at 1550 nm. A BER which is well below the forward error correction (FEC) threshold (5 $\times\, 10^{-5}$ ) was reached for different MCF links.

A novel architecture for the On Off Keying (OOK) modulator with high gain and high data rate power amplifier (PA) operating at 11.6 GHz IBM 0.18-µm RF CMOS technology is presented for a X-band passive RFID tag. Currently used low frequency switching techniques such as multiplexers were not functioning in the high frequency X-band architectures. In this novel approach OOK modulator with power amplifier, a CMOS switch was used to transmit ‘1’ and ‘0’ coming from the digital signal unlike in the existing low frequency architectures. Both the load and driver in this proposed PA were class A operation supplied by a single ended 1.83V source. The important design considerations include output power, 1 dB compression point and linearity. The fabricated results of the amplifier have a 1 dB compression point of 1.2 dBm and input power of 5.19 dBm at 9.2 GHz.

In medical treatment, healthcare and home appliances, the demand for Internet of Things (IoT) services is increasing in urban areas. However, in fading environments of urban area, the existing IoT communication system can degrade severely. The purpose of this paper is to develop a new IoT communication technology that improves communication performance in fading channels. IoT communication systems are aiming at low power long distances. In addition, the amount of data transmission is small due to the service requirements. To achieve this goal, existing IoT communication modems are designed with narrowband signals. However, narrowband signals may cause performance degradation in a frequency selective fading channel environments in urban area. In this paper, we propose a split channel two tone OOK (SC-TT-OOK) that implements on-off keying (OOK) using two tones. Unlike the existing OOK by using one tone, SC-TT-OOK uses spaced two tones to improve communication performance in fading channels. The conventional OOK method has a similar characteristic to that of the existing IoT modems with a narrow bandwidth spectrum. The proposed SC-TT-OOK is OOK using two separated tones. Since the proposed modulation uses two tones, it requires twice the frequency resources of the conventional OOK. However, if the frequencies of the two tones are sufficiently spaced apart, frequency diversity gain can be achieved in the frequency selective fading channels, and communication reliability can be improved in urban environments. The proposed SC-TT-OOK is examined through computer simulation. The simulation results show that the proposed scheme outperforms the conventional scheme in the frequency selective fading channel. Therefore, the proposed method can be used as an alternative technique for IoT modem in urban environments.

In this paper, a novel two dimensional (2D) wavelength/time (W/T) optical code division multiple access (OCDMA) code with zero cross-correlation property to minimize multiple access interface (MAI) is addressed. The code is constructed using various features of two different one-dimensional codes, i.e., multi-diagonal code and prime hop code referred as multi-diagonal prime hopping (MDPHC) code. The proposed 2D W/T MDPHC code is generated using java software version 8.1, which is found to be optimal. In this paper, the code complexity of the proposed 2D code is also derived. In addition to the novel 2D code design, security provision at the photonic layer of the OCDMA network is also addressed by transmitting the data through a novel encrypted circuit in order to prevent attacks by an eavesdropper. In this work, the proposed encryption circuit is integrated with the proposed 2D (W/T) MDPHC OCDMA encoder to enhance the overall security performance. The proposed model is validated using optisystem software version 14. Robustness of the proposed technique against different types of attacks such as ciphertext-only attack, known plain text attack, chosen plaintext attack, energy detection attack in on off keying optical code division multiple access, Brute-force search attack is investigated theoretically. Bit error rate is also estimated for different fiber distances.

This paper presents a G-band on-off -keying transmitter and a G-Band receiver in 65-nm bulk CMOS process. The proposed transmitter includes a high-efficiency push–push voltage-controlled oscillator (VCO) with body-bias and a switch-based modulator using the folded coupled-line topology. The benefits of the folded coupled-line in switch design are theoretically analyzed and proved. The receiver utilized a topology based on envelope detector and inverter-chain-based output buffer. The standalone VCO demonstrates a peak dc-RF efficiency of 4.1% at 209 GHz with 1.02 dBm output power. The switch-based modulator performs a minimum insertion loss of 1.6 dB with isolation better than 21 dB. The transmitter exhibits a maximum output power of −0.04 dBm at 208 GHz with 3% efficiency and a phase noise of −84.9 dBc at 1-MHz offset. The transmitter and receiver achieve 7.5-Gb/s errorless [bit error rate (BER) < 1 × 10−12] data rate with 1.73 pJ/b energy efficiency and 9 Gb/s with 1 × 10−4 BER in loop-back test. The results of both the transmitter/receiver and standalone components show competitive performances at the frequency over 200 GHz among the designs in CMOS process.

This paper presents a new on–off keying modulation circuit for a Class-E power transmitter used in high-data-rate wireless links used for powering medical implants. A circuit technique is proposed to keep the current of the RF choke of the power transmitter constant, while the transmitter turns on and off. This allows the transmitter to quickly turn on and off. To prove the feasibility of the proposed circuit, a wireless power and data transfer link based on the proposed circuit was designed and implemented. At a carrier frequency of 2.5 MHz, the measured data rate was 625 kbps, which means that a data-rate-to-carrier-frequency ratio of 25% has been achieved. The power transfer efficiency and the power delivered to the load, with a 2.37-μH transmitter coil and a 1.4-μH receiver coil separated by a 1.0-cm air gap, were measured to be 21% and 80 mW, respectively. The measured bit error rate of the link was less than 10−5.

The practical development of WUSN would benefit numerous applications, including online infrastructure monitoring, earthquake warning systems, and agricultural automation. However, stateof- the-art RF electromagnetic wireless systems are ineffective for communicating through-soil, due to extreme signal path losses from absorption and scattering in soil, even though the typical data requirements for such applications are modest, ranging from tens to hundreds of bps. In contrast, elephants, rodents and a wide variety of insects use acoustic waves for communicating through-soil, suggesting the viability of soil as a communication channel, and of acoustic waves as carriers. In this article, we demonstrate how soil can be used as a communication medium for wireless acoustic digital communication over distances up to 50 m at 20 bps data rates. By leveraging a physical model of the soil channel derived from its identified characteristics, then employing QPSK and OOK modulation and sparse decision feedback equalization schemes, and exploiting well-coupled and matched acoustic sources, wireless digital communication was successful in both laboratory and field experiments, illustrating the viability of sending application- specific data, ranging from binary sensor readings to low-resolution images.

In the paper, we present and investigate an integrated wavelength-division-multiplexing (WDM) free space optical (FSO) fiber access network for 51 km long-reach connection. Here, the proposed network architecture also can mitigate Rayleigh backscattering (RB) interferometric beat noise. We employ symmetric $4\times 10$ Gbit/s on-off keying (OOK) WDM-FSO downstream and upstream wavelengths for demonstration. According to the simulated and experimental results, the free space transmission length of 400 to 940 m can be achieved based on various WDM-FSO downstream signals and their corresponding power budget, when the wavelengths are without optical amplification.

In this study, we built a single photon avalanche diode (SPAD) receiver based underwater wireless optical communication (UWOC) system. The bit error rate (BER) and signal-to-noise ratio (SNR) performance of UWOC with different distances and data transmission rates were obtained. Based on the water attenuation coefficient of 0.12 m-1, a series of neutral density (ND) filters were exploited to attenuate the light output power from the blue laser diode (LD) to simulate the long distance UWOC. The maximum estimated distances of 144 m and 117 m with corresponding BERs of 1.89 × 10-3 and 5.31 × 10-4 at data transmission rates of 500 bps and 2 Mbps were acquired in UWOC system using on-off keying (OOK) modulation scheme, respectively. Furthermore, we compared the differences between free-space and underwater channels, and a divergence angle of ~1.02 mrad was measured experimentally at a distance of 50 m in the free space. The long UWOC distances obtained in this study partly benefit from high sensitivity SPAD, the small laser divergence angle and low light attenuation. This study provides an approach to achieve long distance UWOC using SPAD.

This study investigates the performance of scintillation mitigation for linear polarization shift on-off keying (LPS-OOK) transmission in free-space optical (FSO) communications. Scintillation effect is a critical issue for FSO communication in vertical links. The LPS-OOK signal with orthogonal linear x- and y-polarizations for bits ‘1’ and ‘0’ is modulated and transmitted from the transmitter end. The bits ‘1’ and ‘0’ suffer the scintillation effect in turbulence channel. Based on the orthogonal polarization characteristics of LPS-OOK, linear polarizer (LP) is used to mitigate the scintillation effect on bit ‘0’ by blocking its polarization without the distortion of bit ‘1’. Further, owing to the nonlinear gain characteristics of logarithmic amplification, it is used to equalize the intensity fluctuation of bit ‘1’. Finally, the equalized LPS-OOK is distinguished using fixed threshold decision (FTD) instead of a complex symbol-by-symbol estimation of adaptive threshold. The performance of the proposed technique was verified experimentally for various degrees of the turbulence channel. A Mach–Zehnder modulator (MZM)-based turbulence channel simulator was adopted to accommodate turbulence-induced scintillation effect. The experimental results confirmed that the proposed technique that employed FTD has an improved bit-error-rate (BER) performance compared with that of OOK that employed an adaptive threshold decision (ATD) under various degrees of turbulence channels.

This letter presents the design of a 120-GHz wireless link. The link incorporates a 28-nm CMOS ON–OFF keying transceiver with on-chip antennas to launch the mm-wave signal into a flexible dielectric fiber. The flexible fiber is connected to a 3D-printed high-gain lens proposed to overcome the high free-space path loss to achieve a 15-dBm EIRP. The receiver consists of a low-noise amplifier with 24.9 dB of voltage gain and covers 42-GHz BW−3dB. An efficient self-mixing envelope detector demodulates the amplified signal back to baseband. Using the proposed flexible fiber and wireless topology, a data rate of 11 Gb/s is demonstrated and distance of 1 m is reached with a power consumption

We demonstrate a high-efficiency silicon Mach-Zehnder modulator with U-shaped PN junctions. The depletion region of the U-shaped PN junction has a large overlap with the waveguide optical mode, leading to a low drive voltage. The calculated modulation efficiency is 0.33 V·cm at 0 V bias and 0.55 V·cm at −2 V bias. On-off keying (OOK) modulation and four-level pulse amplitude modulation (PAM-4) are achieved at 32 Gb/s and 64 Gb/s data rates under 2 V drive voltage, respectively. The bit error rate for the PAM-4 modulation is below the hard-decision forward error correction threshold of 3.8 × 10−3.

All-optical DQPSK to OOK modulation format conversion using cross-polarization modulation in highly nonlinear fiber is proposed. Numerically investigated conversion performances by BER and eye-diagram show that error-free format conversion is successfully achieved.

Minimization of power consumption is one of the most challenging issues in sub-mm implanted devices for wireless neural signal recording. In this work, targeting at a brain model, we firstly perform ultrasound field simulation to find the optimal ultrasound frequency for power transmission. Then we present an ultra-compact low-power communication system through on-off keying (OOK) modulation to transmit the events of neural spikes. An analog-front-end (AFE) is proposed to filter and amplify the action potentials in a non-linear way, yielding a low power consumption of $14.1\ \mu W$ and a silicon area of 0.21 mm2 in a 55 nm process.

The space-based integrated information network is composed of space-based backbone network, space-based access network and ground-based node network. It is interconnected with the ground Internet and mobile communication network to build a “ global coverage, on-demand access, on-demand service, safe and reliable ” space-based integrated information network system. As an important part of the system, the space-ground laser communication equipment is faced with many problems, such as the integration of multiple modulation systems and the location of different places. In this paper, the related problems are analyzed and verified by experiments. The results show that the system works at 1550nm wavelength, adopts coherent communication system and IM/DD communication system, coherent communication system supports BPSK, QPSK and DPSK modulation format, IM/DD communication system adopts OOK modulation format, the communication rate reaches 5Gbps under the condition of 1E-9 bit error rate.

Nowadays, free space optics (FSO) technology is one of the emerging technologies utilized as a complementary over radio frequency wireless technology with limited spectrum bandwidth to meet the high bandwidth demand. FSO technology fulfills the demands for massive bandwidth, faster data rate and low installation and maintenance cost. However, FSO transmission links for outdoor networks are vulnerable to atmospheric turbulence specifically in harsh weather conditions in which it deteriorates the performance of FSO systems. In this paper, a critical study on the performance of the FSO links in different dust storm conditions is presented. We aim to analyze the performance factors such as transmitted power control and link length that contribute to increase in signal-to-noise (SNR) ratio and bit-error-rate (BER) for On-Off Keying (OOK) modulation scheme. The results indicate that under low visibility, shorter link length performs better while increase in transmitted power contributes to small improvements. In contrast, at higher visibility, power control makes significant difference. A "9dbm" power increase over 1km link contributes 400m visibility improvement for OOK modulation. However, these visibility improvements will degrade proportionally as the link length is reduced.

This work presents a wireless 401-406 MHz on-off keying (OOK) transceiver (TRX) analogue front-end for medical implantable communication systems (MICS). The transmitter (TX) part consists of a voltage-controlled oscillator (VCO), a fractional-N phase-locked loop (PLL) and an output buffer for OOK modulation. The receiver (RX) front-end implemented based on a low intermediate-frequency (IF) homodyne RX architecture comprises a balun low-noise amplifier (LNA), a Gilbert mixer and a variable gain amplifier (VGA). The RX re-uses the signal generated by the TX as its local oscillation (LO) signal. A proof-of-concept circuit prototype has been fabricated in a 180-nm BiCMOS technology. Experimental results show the PLL frequency can be adjusted over the entire MICS band with a frequency resolution of 0.33 MHz. Its phase noise is -100 dBc/Hz at 1-MHz offset frequency. Additionally, the TX exhibits a maximal output power of 4.6 dBm. The complete RX front-end achieves a noise figure below 8.4 dB and a high conversion gain of 75 dB. The TX and RX consume a DC power of 23 mW and 27.5 mW, respectively. The data rate of the whole TRX reaches 1 Mbit/s which is the highest among the state-of-the-art MICS TRXs.

In the present communication, the characterization results of an in-house developed four-quadrants detection module based on HgCdTe APDs and a Si-CMOS ROIC pre-amplifier is discussed. The module has been designed to be employed as high data rate ground-segment detector for 1.55 μm long-distance free-space optical communication links in the framework of a project funded by the European Space Agency. The detector is characterized by a multiplication gain in excess of M = 150, a ROIC input referred noise of Ne = 45 electrons rms and a measured bandwidth of BW = 450 MHz. These characteristics enable the linear-mode detection of meso-photonic states ranging from tens of photons per pulse down to the single-photon level at high count rates exceeding 500 MHz per quadrant (and 2 GHz if the signal is dispatched over all four-quadrants). For the present module, the performance for PPM and OOK modulation formats was estimated and its potentiality for long-distance free-space optical communications employing these modulation formats was validated. In particular, for the PPM format, a detection probability of 0.9 and a false alarm probability of 10-2 , a minimum PPM slot width of 500 ps and a temporal jitter with a FWHM ~ 160 ps were estimated, for an incident photonic state with 10 photons/pulse. The potentiality of the detector for 625 Mbps OOK modulation format was also evaluated and compared with a quantum limited situation. In this case, a -3.9 dB penalty from the quantum limited BER was obtained. A new generation of detectors is currently in development, which is expected to further improve the performance.

This paper presents a low cost, compact, short-reach contactless data link designed for M2M applications requiring a full 360° rotational freedom. Full rotational freedom is enabled by a 16 GHz split-ring resonator (SRR) based near field coupler (NFC) which provides a fourth order bandpass characteristic with a 4 GHz bandwidth and ~2 dB insertion loss. The link employs 65 nm CMOS TX and RX chipsets for OOK modulation and demodulation of a 16 GHz carrier. The end-to-end contactless link is demonstrated with a variable gap (0.1 mm to 0.7 mm) and rotation angle (covering full range of 360°) between the TX and RX boards. Additionally, a BER 2Gbps (BER

An overall bit rate of 625 Mb/s real-time multi-access VLC system is presented in this paper. In order to decrease the effect of ambient light and deal with the non-linearity of LED, we propose a new algorithm to get orthogonal codes which is suitable for OOK modulation. By employing a single white LED and three photo diodes, three users are provided access to the VLC system individually at the same time. A data frame and CRC32 are adopted to realize a reliable and continuous data interaction between Ethernet and VLC system. All the numerical calculations are implemented by FPGAs so as to provide a practical high-speed transmission.

This paper presents a 60-GHz transceiver for low-power high-speed short-range wireless using the proposed binary-phase on-off keying (BPOOK) modulation scheme. The proposed BPOOK wireless transceiver transmits radio frequency (RF) signal with amplitude modulated on and off by input baseband data, and meanwhile, the phase is changing between 0° and 180°. The BPOOK transceiver achieves doubled spectral efficiency compared with OOK modulation and binary-phase-shift keying (BPSK) modulation. It also cancels the intrinsic local-oscillator feed through (LOFT) issue in the OOK modulation. The BPOOK RF signal can be demodulated by employing low-power square-law envelope detector incoherently. The transceiver is fabricated in a standard 65-nm CMOS technology. A data rate of 3.0 Gb/s is achieved while consuming a power of 100 mW from 1-V supply. The incoherent receiver has a sensitivity of −46 dBm. The core area of the transceiver is 1.56 mm2.

The recent emergence of efficient O-band amplification technologies has enabled the consideration of O-band transmission beyond short reach. Despite the O-band being a low chromatic dispersion (CD) window, the impact of CD will become increasingly significant when extending the reach of direct-detection (DD) systems. In this work, we first numerically investigate the 3-dB bandwidth of single-mode fibers (SMF) and the CD-restricted transmission reach in intensity-modulation DD systems, confirming the significant difference between low- and high-dispersion O-band wavelengths. We then carry out experimental transmission studies over SMF for distances of up to 70 km at two different wavelengths, the low-dispersion 1320 nm and the more dispersive 1360 nm, enabled by the use of an O-band bismuth-doped fiber amplifier as a preamplifier at the receiver. We compare three 50-Gb/s optical DD formats, namely, Nyquist on-off keying (OOK), Nyquist 4-ary pulse amplitude modulation (PAM4) and Kramers–Kronig detection-assisted single-sideband quadrature phase shift keying (KK-QPSK) half-cycle subcarrier modulation. Our results show that at both wavelengths, OOK and QPSK exhibit better bit error rate performance than PAM4. When transmitting over 70-km of SMF at the less dispersive wavelength of 1320 nm, 50-Gb/s OOK modulation offers more than 1.5-dB optical power sensitivity improvement at the photodiode (PD) compared to 50-Gb/s QPSK. Conversely, at 1360 nm, the required optical power to the PD can be reduced by more than 3 dB by using QPSK instead of OOK.

Wireless technologies that use radio frequency (RF) waveforms are common in wireless communication systems, such as the mobile communication, satellite system, and Internet of Things (IoT) systems. It is more advantageous than wired communication because of the ease of installation. However, it can negatively impact human health if high frequencies are used to transmit data. Therefore, researchers are exploring the potential of optical wireless communication as an alternative, which uses the visible light bandwidth instead of RF waveforms. Three possibilities are being investigated: visible light communication, light fidelity, and optical camera communication. In this paper, we propose a multiple-input multiple-output modulation scheme using a light-emitting diode (LED) array, which is applicable to the IoT system, based on on–off keying modulation in the time domain. This scheme is compatible with the two popular types of camera in the market, rolling shutter cameras and global shutter cameras, as well as the closed-circuit television camera, which is used in factories, buildings, etc. Despite the small size of the LED array, implementing this scheme with 10 links in different positions at a communication distance of 20 m is possible for efficient performance (low error rate) by controlling the exposure time, shutter speed, focal length, channel coding and applying the matched filter.

This paper proposes a semiconductor optical amplifier (SOA)-based multilevel polarization shift on–off keying (MPS-OOK) transmission for free-space optical (FSO) communication. At the transmitter end, the MPS-OOK signal is modulated with a constant linear state of polarization (SOP) at the high-intensity level and various SOPs at the low-intensity level in order to improve the spectral efficiency (SE) with the transmitted power efficiency. At the receiver end, first, a polarization-independent SOA was introduced to optically suppress the turbulence-induced scintillation effect and equalize the intensities of the various SOPs in the deep gain saturation state without polarization distortion. Then, a linear polarizer (LP) with a high extinction ratio (ER) was deployed to convert the equalized SOPs into a known intensity. Finally, the converted MPS-OOK signal was detected using a single photodiode (PD) and distinguished using a multilevel fixed-threshold decision (M-FTD). The proposed technique was evaluated using experiments. A Mach–Zehnder modulator (MZM)-based fading simulator was introduced to emulate the turbulence-induced scintillation effect. The experimental results demonstrated that the scintillation effect was effectively mitigated and the SE was improved by up to 2 bit/s/Hz using the proposed four-level polarization shift on–off keying (4PS-OOK) transmission.

The effort to confine the electromagnetic field by silicon passive metadevices has made the design of an on-chip wideband sub-terahertz (sub-THz) I/O redriver feasible, paving a new way toward energy-efficient and crosstalk-immune ON-OFF keying (OOK) communications. Two metadevices, namely spoof surface plasmon polaritons (SPPs) metawaveguide and split-ring resonator (SRR), are exploited to build the sub-THz low-crosstalk silicon channel and high-ON-OFF-ratio modulator, respectively. A sub-THz signal source combining the merit of spoof SPPs and SRR is introduced. A 140-GHz dual-channel redriver composed of these metadevices is fully integrated in a 65-nm CMOS technology. The redriver realizes both 27-1 and 231-1 13.5 Gb/s/lane for dual-channel OOK modulation. The measured energy efficiency is 2.6 pJ/bit/lane and the bit error rate (BER) is ≤10-12, demonstrating a crosstalk-immune sub-THz I/O system. The power consumption is 35.1 mW/lane and the active area of the redriver is 0.23 mm2. Ministry of Education (MOE) Submitted/Accepted version This work was supported in part by the Singa- pore Ministry of Education Academic Research Fund Tier 2 under Grant MOE2019-T2-1-114, in part by the National Natural Science Foundation of China under Grant 62101122, in part by the Natural Science Foundation of Jiangsu Province under Grant BK20210212, and in part by The Open Foundation of State Key Laboratory of ASIC and System under Grant 2020KF010.

Visible light communication (VLC) is one of the key areas in wireless communication. It has recently been acknowledged as an alternate to RF communication due to increased bandwidth and avoiding health-related impact of RF waves. In the paper, performance of Indoor visible light communication system is analyzed using NRZ-OOK as modulation technique on optisystem 16.1.0. The performance of indoor VLC system is improved using NRZ-OOK modulation in comparison with RZ OOK modulation. Simulation results depict that NRZ-OOK modulation provides optimized data rate of 1 Gb/s up to 6 m distance. BER is also reduced on applying the technique to 1.64851 e-015 bits per sequence.

The goal of this paper is to present the development of an integrated implementation of the transmitter and receiver pair which are designed with intrabody communication (IBC) purposes in mind and uses on-off-keying (OOK) modulation. The system is implemented using Programmable System-on-Chip (PSoC) microcontrollers produced by Cypress, using a minimal number of external components.

Demand for mobile data transfer has driven developing technologies, including optical wireless communications, such as visible light communication (VLC). The high demand has contributed much higher power consumption, which means an increase in carbon emission as well. VLC is an alternative solution for green communication because of its potential applications for both lighting and data transfer simultaneously. In this paper, we study a low-cost VLC system, which consists of two sides, to understanding its performance for digital data transmission. The first part of the transmitting end consists of a microcontroller and an LED. The second part of the receiving end consists of a photodiode and a microcontroller. This research considers OOK modulation, a darkroom to avoid noise from other light sources, and three variables of wavelength spectrums, clock rates, and distances. Parameter observation of bit-error-rate or BER shows that the average BER of LED in white color has smaller BER than red, green, and blue LED, which 0.377, 0.412, 0.387, and 0.387, respectively. From this research, we obtain an insight into sufficient received power and component characteristics that are necessary for developing effectively VLC systems.

This article belongs to the Special Issue Terahertz Sensing and Imaging Technologies. In this work, we present a multipurpose photonic integrated circuit capable of generating multiheterodyne complex Dual-Combs (DC) THz signals. Our work focuses on translating the functionality of an electro-optic tunable DC system into a photonic chip employing standard building blocks to ensure the scalability and cost efficiency of the integrated device. The architecture we analyze for integration is based on three stages: a seed comb, a mode selection stage and a DC stage. This final DC stage includes a frequency shifter, a key element to improve the final detection of the THz signals and obtain real-time operation. This investigation covers three key aspects: (1) a solution for comb line selection on GHz spaced combs using OIL or OPLL on photonic chips is studied and evaluated, (2) a simple and versatile scheme to produce a frequency shift using the double sideband suppressed carrier modulation technique and an asymmetric Mach Zehnder Interferometer to filter one of the sidebands is proposed, and (3) a multipurpose architecture that can offer a versatile effective device, moving from application-specific PICs to general-purpose PICs. Using the building blocks (BBs) available from an InP-based foundry, we obtained simulations that offer a high-quality Dual-Comb frequency shifted signal with a side mode suppression ratio around 21 dB, and 41 dB after photodetection with an intermediate frequency of 1 MHz. We tested our system to generate a Dual-Comb with 10 kHz of frequency spacing and an OOK modulation with 5 Gbps which can be down-converted to the THz range by a square law detector. It is also important to note that the presented architecture is multipurpose and can also be applied to THz communications. This design is a step to enable a commercial THz photonic chip for multiple applications such as THz spectroscopy, THz multispectral imaging and THz telecommunications and offers the possibility of being fabricated in a multi-project wafer. This research was supported by Instituto Tecnológico Metropolitano, Universidad Carlos III de Madrid, the EU H2020 Celta project under Grant Agreement 675683, by the Spanish Ministry of Economy and Competitiveness under Project TEC2017-86271-R and by the ATTRACT project funded by the EC under Grant Agreement 777222.

This paper proposes an ultralow-power wake-up receiver(WuRx) for DSRC (Dedicated Short Range Communication) transceiver application. The proposed WuRx receives 5.8 GHz signal and demodulates it into a 14 kHz on off keyed signal. The proposed WuRx is fabricated in 0.13- µm CMOS technology with the size of 0.26 mm2. At the operating frequency of 5.8 GHz, WuR achieves a -62 dBm sensitivity while consuming 3.3 µW from a 0.9 V supply voltage.

Terahertz (THz) communication is a potential technology for wireless personal area networks. In this paper, we develop a chip set for on-off-keying (OOK) modulation based THz transceivers which include carrier generators, modulators, THz amplifiers, and baseband amplifiers. Specifically, the chip set integrates the circuit blocks for the OOK modulation. In addition, it also includes the THz amplifier modules to extend the coverage of transmission. For this chip set, we experimentally demonstrate the feasibility of the wireless communication at THz frequency bands and assess performance using the bit error rate (BER) analysis. We estimate the BER results by calculating the signal-to-noise ratio (SNR) based on the eye diagram and confirm the accuracy by comparing with actual BER tester measurements and Monte Carlo simulations.

In multi-user optical wireless communication (OWC) systems interference between users and cells can significantly affect the quality of OWC links. Thus, in this paper, a mixed-integer linear programming (MILP) model is developed to establish the optimum resource allocation in wavelength division multiple access (WDMA) optical wireless systems. Consideration is given to the optimum allocation of wavelengths and access points (APs) to each user to support multiple users in an environment where Micro, Pico and Atto Cells co-exist for downlink communication. The high directionality of light rays in small cells, such as Pico and Atto cells, can offer a very high signal to noise and interference ratio (SINR) at high data rates. Consideration is given in this work to visible light communication links which utilise four wavelengths per access point (red, green, yellow and blue) for Pico and Atto cells systems, while the Micro cell system uses an infrared (IR) transmitter. Two 10-user scenarios are considered in this work. All users in both scenarios achieve a high optical channel bandwidth beyond 7.8 GHz. In addition, all users in the two scenarios achieve high SINR beyond the threshold (15.6 dB) needed for 10-9 on off keying (OOK) bit error rate at a data rate of 7.1 Gbps.

We realize signal transmission with a miniature light source fabricated by a 4 m m 2 red-emissive CdSe/ZnS quantum-dot light-emitting diode (QLED) in visible light communication (VLC). The light emitted from the 60°-designed QLED transmits in free space with a data rate of 4 Mb/s at a 3 m transmission distance by using a simple modulation scheme of non-return-to-zero on-off keying. The maximum data rate of 2.5 Mb/s with a bit error rate below the forward-error-correction (FEC) limit is achieved with the optical angles of ± 20 ∘ . The influences caused by the voltage, distance, and optical angle of emitting light are taken into consideration during communication. The performance of the QLED-based light source compares favorably with other solution-processed devices in efficiency, luminance, bandwidth, transmission speed, and distance. Additionally, to the best of our knowledge, this is the first report of an investigation on the application of QLED in VLC. Our results should be instructive for further investigation on QLED communication.

A -108dBm sensitivity, 430MHz, 130nW-41µW, 6.25bps-4.2kbps, digitally tunable wake-up and data receiver in 65nm CMOS is presented. Employing 2-tone RF OOK modulation and an AlN MEMS resonator, the receiver attains close-in SIR of -25dB at 0.12% and far-out SIR of -28dB at 0.7% frequency offset from the carrier. Digitally configurable dynamic ranges of 11dB, 410X, 672X are achieved for sensitivity, power, and latency, respectively. The design receives data at a 4.2kbps bit-rate at - 108dBm sensitivity while consuming 41µW. The proposed WuRx is a highly reconfigurable and interference robust candidate for emerging ultra-long range IoT LPWAN applications.

This publisher’s note contains corrections to Opt. Lett. 45, 758 (2020)OPLEDP0146-959210.1364/OL.384168.

With the advent of Wireless networks, the communication industry has swelled up to a commendable level. Today, communication link establishment between any corners of the world is not a myth anymore because of the research and development of the vast wireless networks. Another technology that serves as the skeleton of these wireless networks is the Optical fibre communication system. The part of the electromagnetic spectrum utilized in the Wireless networks mainly includes the Radio frequency (RF) range and the Microwave range (3 kHz to 30 GHz) which requires broadcast licensing. With the ever-increasing number of users, the allocation of the RF spectrum becomes a major issue. Other disadvantages of the RF and microwave wireless networks have compelled researchers to develop other parallel technologies. One of the mentionable recent technologies that gained fame is the Free Space Optical (FSO) Communication System which combines both the aforesaid technologies into one. This new technology exploits the Visible (400-700 nm) and Infrared (700 nm- 1 mm) region of the EM spectrum. This paper interprets the development of a Field Programmable Gate Array (FPGA) based half duplex terrestrial FSO Communication system using an 808 nm (IR), 100 mW DPSS LASER source. The Line of Sight (LOS) communication link distance is 40 feet. The communication protocol implemented in the design is Serial Communication with a data rate of 115.2 Kbps and the modulation technique used is On Off Keying (OOK).

This article presents a high energy efficiency, high-integrated, and low-power on–off keying transceiver for a 2.4 GHz industrial scientific medical band. The proposed receiver includes an input matching network, a low-noise amplifier, a novel single-to-differential envelope detector, a level shifter, cascaded baseband amplifiers, and a hysteresis comparator. The proposed transmitter includes a bias-stimulating circuit, a current-reused self-mixing voltage controlled oscillator, and a quadruple-transconductance power amplifier. Numerous proposed techniques implemented in the mentioned circuits improve the energy per bit and power efficiency. Therefore, the proposed receiver for short-distanced propagation can achieve a sensitivity of −46 dBm with a carrier frequency of 2.45 GHz and a high data rate of 2 Mbps. The proposed transmitter achieves an output power of −17 dBm with a high data rate of 20 Mbps. This work is fabricated in a TSMC 0.18 μm CMOS process and consumes 160 μW and 0.6 mW in the receiver and transmitter, respectively, from a 1.2 V supply voltage. The energy per bit of 80 pJ/bit in the receiver part and the figure of merit of 9 in the transmitter part are better than those of existing state-of-the-art transceivers.

As mentioned in Chap. 7, transmitter-side OOK modulation can realize MEO without adding any extra components or changing any hardware of a WPT system which typically consists of an inverter in the primary side and a diode bridge rectifier in the secondary side. This chapter introduces the OOK modulation to maintain high-efficiency operation for SS WPT systems over a wide load range. By determining the optimal input voltage for a given output voltage in an SS WPT system, MEO can theoretically be achieved independently of the load.

We use a deep learning neural network to successfully indicate when an eavesdropper is present in a free-space optics ON-OFF keying communication scheme, in which the bit stream has passed through turbulence.

With the convergence towards 5G, optical networks need to be upgraded to support the emerging data tsunami. This work experimentally demonstrates the first real-time transmission of 20 Gbps over a class 10G 1550 nm vertical cavity surface emitting laser (VCSEL) in the context of on-off-keying (OOK) modulation format, by employing VCSEL differential drive mode technique, for adoption in high-speed gigabit passive optical networks (GPONs). Two OOK data streams each with 10 Gbps are differentially modulated onto a single VCSEL, therefore generating an aggregated data rate of 20 Gbps OOK signal. A receiver sensitivity of -13.36 dBm is experimentally achieved. Through extinction ratio optimization, an error free transmission over 24.7 km single mode fibre is attained, with a transmission penalty of 1.91 dB. Our proposed technique alleviates band-limitation of the VCSEL carrier, and doubles the channel data rate without replacing the transmitter optics.

In this paper, an ultra-fast all-optical modulator, based on a new shape of nonlinear photonic crystal ring resonator, is designed and studied. Numerical methods such as plane wave expansion (PWE) and finite-difference time domain (FDTD) are used to perform simulations. The modulation technique consists of carrier light controlling by means of input light signal and Kerr effect. The investigation of extinction ratio and insertion loss within the carrier input power shows that the choice of 0.7 W is the optimal value of that power to ensure the tradeoff between both characteristics. The suggested modulator demonstrates an excellent extinction ratio about 20.8018, a very low insertion loss of −13.98 and a short switching time about 13.4 ps. According to the obtained results, the modulator can be considered as an ultra-fast and ultra-compact optical component.

We address full-duplex relaying for optical wireless communication with stochastic and non-negligible self-interference at the relay node with on-off keying modulation. Assume a relay communication system with a source node, a relaying node, and a destination node, where there is no interference at the source and destination nodes, since they merely transmit or receive. We propose two full-duplex relay protocols, namely, the detect-and-forward relaying protocol and the decode-and-forward relay protocol. For the former, the relay node performs the symbol detection and forwards the detected symbols to the destination node, and for the latter, the relay node performs block decoding and forwards the re-encoded block to the destination node. We prove that for sufficiently high self-interference intensity, the achievable transmission rate of the full-duplex relay system can be lower than that of the half-duplex relay system without self-interference for the detect-and-forward relay protocol. We also prove that for the decode-and-forward relay protocol, the full-duplex relay system always has a larger transmission rate compared with the half-duplex relay system. This can be justified by the fact that, for the decode-and-forward protocol, the source-relay link adopts two codebooks in the scenarios with and without self-interference. The performance of the two proposed protocols is evaluated by the numerical results.

In the free-space optical (FSO) links, atmospheric turbulence lead to scintillation in the received signal. Due to its ease of implementation, intensity modulation with direct detection (IM/DD) based on ON–OFF keying (OOK) is a popular signaling scheme in these systems. Over turbulence channel, to detect OOK symbols in a blind way, i.e., without sending pilot symbols, an expectation–maximization (EM)-based detection method was recently proposed in the literature related to free-space optical (FSO) communication. However, the performance of EM-based detection methods severely depends on the length of the observation interval ( L s ). To choose the optimum values of L s at target bit error rates (BER)s of FSO communications which are commonly lower than 1 0 − 9 , Monte-Carlo simulations would be very cumbersome and require a very long processing time. To facilitate performance evaluation, in this letter we derive the analytic expressions for BER and outage probability. Numerical results validate the accuracy of our derived analytic expressions. Our results may serve to evaluate the optimum value for L s without resorting to time-consuming Monte-Carlo simulations.

An interface IC for medical implants is implemented by using RF techniques of carrier synthesis and wireless powering. An external RF signal at 1.608 GHz is shared by an RF-dc converter and an injection-locked divide-by-four circuit, where most of the RF energy goes to the former for RF energy harvesting and the rest of it serves as the injection signal for the latter to generate a low-phase-noise carrier at 402 MHz. Through an on-chip digital control unit and a successive approximation register analog-to-digital converter, biomedical signal in digital form can be obtained and then used to control the bias voltages of a power amplifier (PA) to perform the OOK modulation for wireless transmission. It requires an input level of 8 dBm to operate the chip. The 402-MHz carrier exhibits a phase noise of −136.7 dBc/Hz at an offset frequency of 1 MHz and the PA delivers an output power of −19.7 dBm.