A Review of Silicon-Based Integrated Optical Switches

Recently, silicon-integrated optical circuits have attracted intensive interests, thanks to the compatibility with the complementary metal-oxide-semiconductor (CMOS) technology that enables mass production at low cost. The optical switch is an essential part of optical integrated circuits, with broad applications in optical communications and networks, optical computing, and sensing such as LiDAR. In general, the silicon-integrated optical switch adopts thermo-optic or carrier dispersion effect to realize reconfigurable signal routing. However, the use of thermo-optic effect leads to high power consumption, and the carrier dispersion effect has the disadvantage of small refractive index change. In addition, both effects are non-latching, and hence, continuous power consumption is required even when switching is not needed. For overcoming these drawbacks, phase-change materials (PCMs) have been introduced into silicon-integrated optical switches. In this paper, silicon-integrated optical switches are classified according to the underlying structure and recent research is reviewed. Recent studies on silicon-integrated optical switches incorporating PCMs are also reviewed. Furthermore, the pros and cons of different types of integrated optical switches with and without PCMs are compared and discussed.

Automated summary

Silicon-integrated optical circuits have been gaining significant attention due to their compatibility with CMOS technology, enabling low-cost mass production. Optical switches, an integral part of these circuits, have various applications in optical communications, optical computing, and sensing. Existing silicon-integrated optical switches that utilize thermo-optic or carrier dispersion effects have drawbacks of high power consumption and small refractive index change. To address these issues, researchers have incorporated phase-change materials (PCMs) into silicon-integrated optical switches. This paper classifies and reviews the recent research on silicon-integrated optical switches, as well as compares the advantages and disadvantages of different types of switches with and without PCMs.