On-Chip Selective Dual-Mode Switch for 2-μm Wavelength High-Speed Optical Interconnection

In this work, we designed and fabricated a dual-mode switch based on triple-waveguide couplers and two thermal phase shifters, and demonstrated the first silicon-integrated mode division multiplexing (MDM) switching network for $2-\mu \text{m}$ waveband. The proposed dual-mode switch shows < 2.6 dB insertion loss, <−20 dB inter-mode crosstalk at 1960 nm, with broadband operation over 100 nm. The experimental results of dynamic switching at 10 kHz presents 9.2- $\mu \text{s}$ rising time and $13.2-\mu \text{s}$ falling time, with switching power of 19.2 mW. High speed on-chip MDM routing of $2\times 60$ Gbps signal was experimentally demonstrated using the proposed 2- $\mu \text{m}$ MDM switching network, drawing the promising prospect for the future photonic integration and high-speed MDM networking at 2- $\mu \text{m}$ waveband.

I. Introduction

Due to the urgent demand of ultrahigh capacity and ultralow latency for the next-generation optical communication, 2- waveband has been considered as a promising communication window, thanks to the development of hollow-core fiber (HCF) [1] with low loss and low latency, and thulium-doped fiber amplifier (TDFA) [2] with broadband gain. Especially for the short-reach optical interconnection like high performance computing applications, HCF-induced latency reduction and wideband WDM supported by TDFA, make 2- optical interconnection a competitive solution in such capacity/latency-hungry scenarios [3]. The implementation of 2- interconnection also benefits from the key components working at this waveband, including narrow linewidth semiconductor laser [4], high-speed electro-optic modulator [5] and photodetector (PD) [6].