Review of 2 x 2 Silicon Photonic Switches

With the advent of 5G, artificial intelligence (AI), Internet of Things (IoT), cloud computing, Internet plus, and so on, data traffic is exploding and higher requirements are put forward for information transmission and switching. Traditional switching requires optical/electrical/optical conversions, which brings additional power consumption and requires the deployment of large amounts of cooling equipment. This increases the cost and complexity of the system. Moreover, limited by the electronic bottleneck, electrical switching will suffer from many problems such as bandwidth, delay, crosstalk, and so on, with the continuous reduction in device footprint. Optical switching does not require optical/electrical/optical conversions and has lower power consumption, larger capacity, and lower cost. Silicon photonic switches received much attention because of their compatibility with the complementary metal-oxide-semiconductor (CMOS) process and are anticipated to be potential candidates to replace electrical switches in many applications such as data center and telecommunication networks. 2 x 2 silicon photonic switches are the basic components to build the large-scale optical switching matrices. Thus, this review article mainly focuses on the principle and state of the art of 2 x 2 silicon photonic switches, including electro-optic switches, thermo-optic switches, and nonvolatile silicon photonic switches assisted by phase-change materials.

Automated summary

With the emergence of 5G, AI, IoT, cloud computing, Internet plus, etc., the demand for information transmission and switching is increasing due to exploding data traffic. Traditional switching methods require additional power consumption and cooling equipment, while facing challenges such as bandwidth, delay, and crosstalk. Optical switching, particularly silicon photonic switches, provide a potential solution with lower power consumption, larger capacity, and lower cost. This review focuses on the principle and current developments of 2 x 2 silicon photonic switches, including electro-optic, thermo-optic, and nonvolatile switches assisted by phase-change materials.