Out-of-plane focusing grating couplers for silicon photonics integration with optical MRAM technology

We present the design methodology and experimental characterization of compact out-of-plane focusing grating couplers for integration with magnetoresistive random access memory technology. Focusing grating couplers have recently found attention as layer-couplers for photonic-electronic integration. The components we demonstrate are designed for a wavelength of 1550 nm, fabricated in a standard 220 nm SOI photonic platform and optimized given the fabrication restrictions for standard 193-nm UV lithography. For the first time, we extend the design based on the phase matching condition to a two-dimensional (2-D) grating design with two optical input ports. We further present the experimental characterization of the focusing behaviour by spatially probing the emitted beam with a tapered-and-lensed fiber and demonstrate the polarization controlling capabilities of the 2-D FGCs

Design optimization for energy-efficient pulse-switching networks in carrier-injection based Si-photonics

We compare pulse-switching operations in MZI- and ring-switches both experimentally and based on large-signal circuit simulations. With a modification in switch design and with optimization of phase modulator lengths, we show high-speed switches with potential for an over 3 dB improvement in energy consumption

Optical bandgap engineering in nonlinear silicon nitride waveguides

Silicon nitride is awell-established material for photonic devices and integrated circuits. It displays a broad transparency window spanning from the visible to the mid-IR and waveguides can be manufactured with low losses. An absence of nonlinear multi-photon absorption in the erbium lightwave communications band has enabled various nonlinear optic applications in the past decade. Silicon nitride is a dielectric material whose optical and mechanical properties strongly depend on the deposition conditions. In particular, the optical bandgap can be modified with the gas flow ratio during low-pressure chemical vapor deposition (LPCVD). Here we show that this parameter can be controlled in a highly reproducible manner, providing an approach to synthesize the nonlinear Kerr coefficient of the material. This holistic empirical study provides relevant guidelines to optimize the properties of LPCVD silicon nitride waveguides for nonlinear optics applications that rely on the Kerr effect

Impact of optical free-carrier generation on the performance of SOI phase shifters

We provide measurement and simulation data of optical free-carrier generation in SOI phase shifters. We conclude that phase impairments caused by unwanted free-carriers can be equalized with an similar to 50% increase in phase shifter diode current. (c) 2020 The Author(s

Out-of-plane focussing polarization control grating couplers for photonic-spintronic integration

We demonstrate the first out-of-plane 2D focusing grating coupler (FGC), designed for compact photonic-spintronic integration allowing full polarization control of the emitted light. The couplers are designed for a standard 220nm-SOI platform and fabricated with 193 nm UV lithography. These couplers can find applicability as polarization (de)multiplexers, optical layer couplers or to realize optically enabled spintronic memory based on helicity dependent all-optical switching (AOS)[1,2]

Continuous wave-pumped wavelength conversion in low-loss silicon nitride waveguides

In this Letter we introduce a complementary metal-oxide semiconductor (CMOS)-compatible low-loss Si3N4 waveguide platform for nonlinear integrated optics. The waveguide has a moderate nonlinear coefficient of 285 W∕km, but the achieved propagation loss of only 0.06 dB∕cm and the ability to handle high optical power facilitate an optimal waveguide length for wavelength conversion. We observe a constant quadratic dependence of the four-wave mixing (FWM) process on the continuous-wave (CW) pump when operating in the C-band, which indicates that the waveguide has negligible high-power constraints owing to nonlinear losses. We achieve a conversion efficiency of −26.1 dB and idler power generation of −19.6 dBm. With these characteristics, we present for the first time, to the best of our knowledge, CW-pumped data conversion in a non-resonant Si3N4 waveguide

Wavelength Conversion in Low Loss Si3N4 Waveguides

We show wavelength conversion in a compact Si3N4 waveguide. Combining low loss, long length, relatively large nonlinear coefficient, high-power handling and absence of two-photon absorption, this platform is promising for integrated nonlinear optics applications

Towards high-speed energy-efficient pulse-switching networks implemented in carrier-injection-based si-photonics

We show that carrier injection based Si-photonics modulators [1] can form the basis for building compact, low-loss and power efficient reconfigurable networks, enabling the switching of ps-pulse trains with sub-GHz repetition rates. The use of pre-emphasis-based activation [2] permits ns-scale switching transitions. Although the steady-state energy consumption in this platform is well studied, the impact of the dynamic energy consumption for these ns switching periods is not well known. Here, we show pre-emphasis-based sub-ns transitions and present a novel large-signal analysis that allows the driving scheme optimization for energy-efficient pulse switching