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An integrated microwave photonic (IMWP) reconfigurable mixer, phase shifter, and frequency doubler based on the silicon photonics platform is proposed and theoretically investigated in this paper. The proposed structure consists of a novel dual-drive MachZehnder modulator (DDMZM) placed in parallel with an electro-optic phase modulator (PM). The novel DDMZM is a bias-free modulator that has advantages over conventional MZMs, such as bias-free operation and tunable optical-to-carrier sideband ratio (OCSR). The proposed novel structure can be configured as an IMWP phase tunable mixer or IMWP double-balanced mixer by properly adjusting optical wavelength and choosing the proper radio frequency (RF) hybrid coupler. Besides, the proposed IMWP reconfigurable mixer has the ability to perform up-converting, down-converting, RF frequency doubling, and phase shifting. The proposed structure is theoretically analyzed and is verified by simulations.

Photonic reservoir computing (RC) enables us to introduce artificial neural networks (ANNs) as a deployable hardware-based processing unit beyond the von Neumann architecture. Its unique approach to consider only the output layer weights as adaptive, reduces training complexity and enables the use of ANNs in time-sensitive areas like optical communications. In this paper, we numerically investigate and evaluate the requirements of a photonic RC using an active silicon micro-ring resonator as a photonic integrated circuit (PIC) based reservoir system to compensate for transmission impairments such as chromatic dispersion and nonlinear effects occurring in optical transmission systems. We compare the performance of this RC with results from digital signal processing using Kramers-Kronig reception of distorted PAM-4 symbols from a 56 GBaud WDM transmission experiment over 100 km uncompensated SSMF.

The trade-offs of using thermo-optical phase shifter in different standard CMOS silicon-on-insulator (SOI) structures (strip and rib waveguides) are studied. Twelve different thermo-optic phase shifters, considering metal and highly doped silicon (both n- and p-type), are studied using numerical simulations and measurements. The performance of heater type, size, and distance to the strip waveguide in terms of energy efficiency, crosstalk, and response time is investigated. The required power to reach π phase shift is measured and compared with the numerical simulation. The time response and the corresponding figure of merit of the interferometer affected by each heater is analyzed and the design strategies for optimizing the designs are discussed. A new compact design for the phase shifter is suggested with low thermal crosstalk (ΔT π = 13.2 mW).

Silicon is a common material for photonics due to its favorable optical properties in the telecom and mid-wave IR bands, as well as compatibility with a wide range of complementary metal-oxide semiconductor (CMOS) foundry processes. Crystalline inversion symmetry precludes silicon from natively exhibiting second-order nonlinear optical processes. In this work, we build on recent work in silicon photonics that break this material symmetry using large bias fields, thereby enabling $\chi^{(2)}$ interactions. Using this approach, we demonstrate both second-harmonic generation (with a normalized efficiency of $0.2\,\%\,\mathrm{W^{-1} cm^{-2}}$) and, to our knowledge, the first degenerate $\chi^{(2)}$ optical parametric amplifier (with relative gain of $0.02\,\mathrm{dB}$ using $3\,\mathrm{mW}$ of pump power on-chip at a pump wavelength of $1196\,\mathrm{nm}$) using silicon-on-insulator waveguides fabricated in a CMOS-compatible commercial foundry. We expect this technology to enable the integration of novel nonlinear optical devices such as optical parametric amplifiers, oscillators, and frequency converters into large-scale, hybrid photonic-electronic systems by leveraging the extensive ecosystem of CMOS fabrication., Comment: The first three authors contributed equally to this work; 9 pages, 5 figures

At 850 nm, an array of SiN waveguide-emitters (end-fire) to enable wide beam steering and splitting in a field of view of 60° and is presented. A free-space data rate of 6.25 Mb/s is achieved.

The conditions to achieve bistability for active silicon ring resonators including thermal nonlinearity are investigated. We show that by including the thermal nonlinearity, the power threshold to achieve bistability is reduced.

We demonstrate electric-field-induced second-harmonic generation from 2.4 μm to 1.2 μm in 3 μm-thick silicon ridge waveguides integrated with alternating p-n diodes. Second-harmonic generation as a function of fundamental wavelength tuning is characterized.

This study focuses on the design of photonic hardware for an ECG arrythmia classifier based on convolutional neural network using optical delay lines for the implementation of “multiply and accumulate” (MAC) operations.

Resonance-splitting is measured in active silicon micro-ring resonators, resulting from the coupling between counter-rotating modes. Parameters of the model, using Temporal Coupled Mode Theory (TCMT), are obtained by fitting the model to the experimental results.

The energy efficiency of silicon nitride (SiN) microresonator-based frequency combs is investigated using numerical simulations. The formation of stable frequency comb solutions is numerically studied for a resonator with properly engineered dispersion. The required conditions for the pump power and frequency detuning are analyzed to obtain modulation instability (MI-comb), single soliton, multi-soliton, and soliton-crystal. The performance of the micro combs in terms of the power conversion efficiency, the number of generated comb lines, and line spacing required for different applications of the frequency combs are investigated. Our numerical simulations, based on the parameters of the studied microring, show a configurable multi-wavelength source with up to 23% power conversion efficiency, 200 comb-lines with more than -10dBm power, and switchable line spacing from 100 GHz to 3THz is feasible for different regimes of the proposed frequency comb. The efficiency sensitivity to the input pump power is also studied to find the most energy-efficient operation regime for the multi-wavelength source.

Recent emerging applications in LiDAR, free-space data link, projection, and imaging increase the demand for high performance optical phased array (OPA) [1] – [3] . The radiating elements considered for most applications are mainly diffractive elements such as gratings or photonic crystal waveguides. It has been shown recently that edge-emitting waveguide arrays, also known as end-fire, facilitate subwavelength spacing in IR range, which results in a large beam steering [4] , [5] . For several applications such as data centers, sensing, and spectroscopy, the near-visible infrared OPAs are in high demand. We demonstrated an end-fire-based OPA at a wavelength of 852nm. The OPA is fabricated on a PECVD SiN-on-insulator platform offered by imec available through BioPIX300 technology. The waveguide is designed for the first fundamental mode with a cross-section of 550×300nm 2 . As shown in Fig. 1(a) , the optical input is divided into eight branches using a tree of optically optimized Y-splitters (insertion loss < 0.03dB). After each splitting level, four thermo-optical phase shifters are connected electrically in parallel. Phase shifting is enabled by a TiN heater on top of the waveguide with a length of L=90μm. The effect of thermal coupling length [6] , [7] is considered after the first, second, and third splitter 4L, 2L, and L, respectively. This configuration provides a simple three-level resolution for beam steering resolution, all with the same applied voltage. To reduce the thermal crosstalk, adjacent channels are not active at the same time. Even- and odd channels are separated in an active mode, each responsible for left and right beam steering. The channels finally end at two microns before the chip's edge with a center-to-center spacing of 800nm.

An energy-efficient integrated silicon Mach-Zehnder modulator using 0.5 mm long corrugated waveguides with an extinction ratio of 30 dB is presented. Using this modulator, 15 Gb/s NRZ transmission is demonstrated with modulation efficiency (Vπ L) of 0.065 V.cm.

We demonstrate voltage-tunable thermo-optic bi- and tri-stability in silicon photonic microring resonators with lateral p-i-n junctions and present a technique for characterizing the thermo-optic transient response of integrated optical resonators. Our method for thermo-optic transient response measurement is applicable to any integrated photonics platform and uses standard equipment. Thermo-optic relaxation in encapsulated waveguides is found to be approximately logarithmic in time, consistent with the analytic solution for 2D heat diffusion. We develop a model for thermo-optic microring multi-stability and dynamics which agrees with experiment data over a wide range of operating conditions. Our work highlights the fundamental connection in semiconductor waveguides between active free-carrier removal and thermo-optic heating, a result of particular relevance to Kerr soliton state stability and on-chip frequency comb generation. The devices studied here were fabricated in a CMOS foundry process and as a result our model is useful for design of silicon photonic waveguide devices., 10 pages, 3 figures

In this paper, various components required for the realization of transmitters to be used for short-range optical interconnects are presented and their performance is studied using either numerical simulation or lab measurements. Optical modulators, thermos-optic phase shifters, and frequency combs are investigated in this article.

This paper discusses a novel packaging approach for electro-optical (E/O) co-integration of IC-chips to realize hetero-integrated transceivers for optical chip-to-chip (C2C) communication. For an integration of chip-components into optical transceivers a polymer package fabricated using additive manufacturing methods are applied. Based on two optical transceiver assemblies - VCSEL-based and Si-photonic-based - different requirements on the package are discussed. For the Si-photonic chips measurements on the lateral and angular misalignment requirements have been performed. The results of the characterization of grating couplers show that the maximum lateral misalignment for 1dB-loss vary between ± 1 µm and ± 3.5 µm. For the angular sensitivity the 1dB-tolerances of +/- 2° at the in-coupling interface and of about +/- 0.4° at the out-coupling have been measured. The simultaneous IC-device embedding and chip-carrier fabrication using casting method is proposed. By subsequent build-up of dielectric/metal multilayer stack an electrical and optical redistribution network for routing of both optical and electrical signals can be realized. A hybrid polymer Ormocer® material has been applied as optical and dielectric material enabling the E/O co-integration using one material class. The performance of this material in both domains optical and RF has been proven. Based on attenuation measurements of multimode optical waveguides low-loss transmission of < 0.05 dB/cm at 850 nm wavelength has been shown. Based on transmission-line (TL) measurements in the frequency range of 140 GHz to 220 GHz the superior dielectric properties with TL-losses of about 1.1 dB/mm have been achieved.

With the explosion of the number of compute nodes, the bottleneck of future computing systems lies in the network architecture connecting the nodes. Addressing the bottleneck requires replacing current backplane-based network topologies. We propose to revolutionize computing electronics by realizing embedded optical waveguides for onboard networking and wireless chip-to-chip links at 200-GHz carrier frequency connecting neighboring boards in a rack. The control of novel rate-adaptive optical and mm-wave transceivers needs tight interlinking with the system software for runtime resource management.

Design considerations and guidelines for utilizing an array of silicon nitride grating couplers for point-to-point communication with the ability of two-dimensional (2-D) beam steering are investigated using numerical simulations. A single grating coupler is designed to enable efficient and directional radiation. The spacing of couplers in the array is optimized in order to decrease the level of the cross-talk (

A corrugated based slow-light silicon nitride waveguide is studied numerically to enhance Kerr nonlinearity by increasing the group index of the waveguide at the band edge. The structure is optimized taking into account the limitations existing in CMOS-compatible platforms. Bandwidth limitations of the structure are investigated at different wavelengths for various slow-down factors. Finite size realizations of the structure are studied using transfer matrix method to obtain the desired transmission and group velocity at the band edge. Optical loss corresponding to slow-light effect is modeled, and the limitations imposed by the slow-light loss on the nonlinear phase shift saturation are considered. It is shown that by employing slow-down factor of 3, the nonlinear phase shift is improved by a factor of 5. Also, in comparison with a straight waveguide, shorter corrugated waveguides (up to nine times) can provide the same accumulated nonlinear phase shift.

The energy efficiency of silicon modulators can be enhanced by increasing the doping level. As an alternative solution, slow light modulators based on corrugated waveguides can also be used for improving the energy efficiency. Using numerical and analytical tools, we show that for the same level of energy consumption reduction, the loss coefficient and the loss-modulation efficiency for the slow-light modulators are smaller than those for the modulators with an increased doping level. It is shown that the slow light structures with medium slow down factors (specifically slowdown factors of less than 6) can be reasonable candidates for enhancing the modulator's energy efficiency. For example, an energy consumption of less than 100 fJ/bit can be achieved at a slow-down factor of 6, using a doping level of 5 × 1017 cm-3 for acceptors and 1 × 1018 cm-3 for donors.

The impulse response of a dual pump parametric process in silicon is numerically studied under different scenarios. Strong signal amplification can be seen (up to 30 mW) despite thermal detuning without active temperature stabilization.

Photonic masking enables fully transparent silicon micro-ring-based reservoir computing for channel equalization. We have evaluated the performance of micro-ring-based reservoir computing estimation for a 28GBd SSB PAM-4 transmission setup over 100km SSMF with Kramers-Kronig reception.