Search

We describe a system with multi‐input multi‐output (MIMO) transmission over 7‐core few‐mode fiber (FMF) by incorporating polarization division multiplexing and mode division multiplexing. Three optical modes with x and y polarizations were used for 42 × 42 MIMO transmission over 7‐core FMF. We simulate the optical MIMO transmission at 20 Gbps with quadrature phase‐shift keying signals. By using the adaptive recursive least squares constant modulus algorithm (RLSCMA) at the receiver side, transmission data is successfully recovered by mitigating the effects of modal delay and mode coupling of received signals. The simulation results show that adaptive RLSCMA can improve the system performance of optical MIMO transmission systems. [ABSTRACT FROM AUTHOR]

This paper proposes an efficient optical fiber communication scheme for an optical metro access network (OMAN) based on an optical multicarrier (OMC) generator. The central office (CO)'s foundation is a novel, cost‐effective OMC‐generating technique. The OMC is designed from a pulsed laser source and three cascaded electro‐optic modulators (EOMs) driven by an amplified RF source of 20 GHz signal that has generated more than 60 frequencies with excellent tone‐to‐noise ratio (TNR) ~ 40 dB and amplitude excursions from zero to 3 dB. The conventional CO is replaced with a cost‐effective OMC‐based source with an effective switching mechanism, which is necessary and equally important to be handled reliably. The downstream data of 20 Gbps per carrier is transmitted using a duo‐binary coding scheme. Six remote nodes (RNs) supported by the suggested OMC source, at each RN 10 optical network units (ONUs), can be deployed having distance laps of 5 km between the RNs, the distance between the RNs and the ONUs is kept at 2 km, the ONUs were tested w.r.t the bit error rate (BER) and the power penalties for the proposed transmissions. The BER for different fiber lengths from 5 to 25 km at various RNs and ONUs ranges were calculated and demonstrated from 1e−3 to 1e−13, showing the feasibility of the proposed OMAN. [ABSTRACT FROM AUTHOR]

Solar energy is pollution‐free with less impact on the ecosystem, but it has limitations due to its intermittent nature attributed to sun availability for specific hours, resulting in less energy conservation efficiency. Similar to the purpose of carvings on the leaves to collect water, we are presenting a nanometer‐thick layer of silicon or chalcogenide with fused silica for photons enhancement in red and the blue portion of the spectrum within the solar energy reaching the earth's surface. The design is based on nanorod imprints on micrometer‐sized conventional fused silica, ensuring better absorption and transportation toward hybrid photovoltaic cells. Hybrid solar cells (comprising silicon and perovskites) are typically termed the future of solar power, but will not be discussed here. Effective area, optical power concentration, and second‐ and higher‐order dispersions can further help design and develop the photon concentrators. [ABSTRACT FROM AUTHOR]

Mode‐locking is an increased focus area due to the augmented requirement of ultra‐short and high‐intensity optical pulses for varied applications. Tunable mode‐locked lasers capable of operating in the infrared range at high repetition frequency brought innovative opportunities for insensitive and accurate laser surgery. As one important application of optical pulse propagation in an optical fiber, we have discussed a dual‐ring hybrid mode‐locked fiber laser using modulator, and saturable absorber. The active mechanism, saturable absorber, and the nonlinear optical loop mirror result in an output with a peak power of 16 dBm, and 80 fs full‐width at half‐maximum with a high duty cycle. It occupies a small space and is easy to achieve miniaturization and intensification; the laser output can be adjusted by varying multiple parameters such as pump, input, doped fiber length, modulator (including modulation signal), saturable absorber, and other devices. [ABSTRACT FROM AUTHOR]

A new arrangement of optical frequency comb and its deployment in a wavelength division multiplexed optical network is proposed and demonstrated. The generated optical carriers are separated by a frequency spacing of 10GHz and the overall spectra comprise 63 individual optical carriers. These carriers are identified and separated by utilizing rectangle optical filters, and 10Gbps data is modulated on each carrier frequency. The data is modulated using carrier suppressed return to zero differential phase‐shift keying (CSRZ‐DPSK) modulation technique. Furthermore, the performance analysis of DPSK and CSRZ‐DPSK (presuppressed RZ‐DPSK, postsuppressed RZ‐DPSK, and suppression of multiplexed DPSK signal) are studied in details. In our analysis, it is observed that the three suppression techniques produce almost the same level of suppression, however, the bit error rate and Q factor differ. It has been observed that the postsuppressed DPSK modulation scheme offers more tolerance towards chromatic dispersion and other fiber impairments and nonlinearities such as self‐phase modulation and offers better overall performance. The results are analyzed in terms of BER performance, Q‐factor, and eye‐opening penalty. [ABSTRACT FROM AUTHOR]

Existing analytical models (EAMs) are used to find the quality of service of optical networks with wavelength division multiplexing (WDM). However, the convergence of EAMs decreases with an increase in traffic load and the numbers of wavelength (w) channels. EAMs are used to compute approximated numerical values of blocking probabilities (BPs) which are based on an iterative approach. There are cases in EAMs when numerical BP values do not converge to a single point after numerous iterations. In this paper, the converge issues of EAMs have been addressed by considering a recursive approximation based on iterative approach with the convergence criteria which is called an advance approximated BP model (AABPM). The accuracy of the AABPM for WDM optical networks is examined by comparing with an EAM as well as simulation results which shows that AABPM converges to give similar approximated numerical values with less convergence time. [ABSTRACT FROM AUTHOR]

High‐order pulse modulations in free space optics (FSO) communication are of practical value, and non‐Kolmogorov gamma–gamma (GG) channel model is the most suitable for FSO channel. However, research on a system combined with the above is rarely reported. In our work, we propose high‐order (4*32 and 4*64) amplitude and pulse position modulation (APPM) and overlapping amplitude and pulse position modulation (AOPPM) FSO communication system under a modified non‐Kolmogorov GG turbulent channel model. Simulation results present that AOPPM is obviously better than APPM in bit‐error‐rate (BER) performance, and BER performance grows with the increase of modulation order (number of pulse positions). The proposed schemes may provide a reference for system design and practical application. [ABSTRACT FROM AUTHOR]