Athermal silicon photonics

Abstract

Temperature-dependent change in refractive index of photonic waveguide devices is useful in several applications such as thermo-optic (TO) wavelength tuning and TO switching. The TO effect, however, becomes a significant burden in wavelength-filtering devices such as ring resonators and arrayed waveguide gratings (AWG) which need stable operation independent of ambient temperature. Precise temperature control is usually necessary for the stable functioning of the wavelength filters, and it cannot but cause the problem of high power consumption and high production cost. Silicon has a very high TO coefficient compared to silica, and the temperature dependence is one of the big hurdles that must be overcome to realize a massive commercialization of silicon photonics technology. This chapter reviews the various approaches to overcome the high temperature-dependent wavelength shift of photonic waveguide devices and discuss the possibility of athermal technology suitable for the silicon photonics industry.