Silicon Non-Blocking 4 × 4 Optical Switch Chip Integrated With Both Thermal and Electro-Optic Tuners

Abstract

We experimentally demonstrate an integrated strictly non-blocking silicon 4 × 4 optical switch chip that can be operated in both thermo-optic (TO) and electro-optic (EO) switching modes. It is based on the double-layer network (DLN) architecture and consists of twelve 2 × 2 Mach-Zehnder interferometer (MZI) switch elements. TO phase shifters based on TiN microheaters and EO phase shifters based on p-in diodes are embedded in both waveguide arms of the MZI elements. The power consumption for TO and EO switching is 34 mW/π and 7 mW/π, respectively. The on-chip insertion losses are 1.74 ± 0.59 dB and 3.79 dB ± 1.32 dB for TO and EO switching, respectively. Due to the merits of the DLN architecture and the optimized performance of the switch elements, the chip possesses low crosstalk of −29.1 dB and −19.4 dB for TO and EO switching, respectively. Quadrature phase-shift keying (QPSK) optical signals with a data rate of 64 Gb/s are transmitted through the switch with no observable deteriorations. Such an optical switch is a promising candidate for both optical circuit switching and optical packet switching for a variety of applications.

Ultra-Broadband and Low-Loss Silicon-Based Power Splitter Based on Subwavelength Grating-Assisted Multimode Interference Structure

“…For the device transmission of our proposed power splitter, its value was obviously reduced to −0.08 dB at a wavelength of 1.55 µm upon embedding the extra uniform SWG structures on both sides of the MMI region. Such a low transmission loss of the power splitter would be very beneficial to construct on-chip photonic devices (e.g., MZI modulators [11,12] and optical switches [13,14]) and large-scale PICs. During the calculation process shown in Figure 5, the choice of optimal values of N and L E for every gap length L S was also important.…”

“…With overall consideration of the device size, performance, and fabrication tolerance, MMI couplers are the best choice since Y-branches require a large device size, while DCs and PCs have limited working bandwidths and tight fabrication tolerances, respectively. Therefore, MMI-based power splitters are vital components applied in on-chip Mach-Zehnder interferometer (MZI) modulators [11,12], optical switches [13,14], and other on-chip optical circuits requiring a light power-splitting function [15,16]. Within these application cases, a smaller device size and better device performance have become the new requirements for silicon-based power splitters.…”

A Review of Silicon‐Based Integrated Optical Switches

“…[88] Due to these advantages, MZIs have been used in silicon-based optical integrated circuits since the 1980s. [89] In 2019, a silicon-integrated strictly nonblocking 4 × 4 optical switch was demonstrated by Lu et al [73] The optical switch where the signal (green lines) routes from input 1 to output N, the yellow lines show the first order crosstalk, and the red lines show the second order crosstalk; and b) schematic of the micro-ring-based crossbar topology, where the signal (green lines) routes from input 1 to output N, and the yellow lines show the first order crosstalk. (re-drawn from [72] ).…”

CrossLight: A Cross-Layer Optimized Silicon Photonic Neural Network Accelerator

“…We propose to use a hybrid tuning circuit where both thermo-optic (TO) and electro-optic (EO) tuning are used to compensate for ΔλMR. Such a tuning approach has previously been proposed in [22] for silicon photonic Mach-Zehnder Interferometers with low insertion loss. Such an approach can be easily transferred to an optimized MR for hybrid tuning in our architecture.…”