Thermo-optic coefficient of silicon at 1550 nm and cryogenic temperatures

Abstract

The thermo-optic coefficient d n / d T of silicon was measured at 1550 nm in the wide temperature range from 5 K to 300 K. For this purpose an interferometric measurement scheme was applied using the silicon sample as a Fabry-Perot etalon. The high resolution of this setup revealed a thermo-optic coefficient as low as 10 -8 K -1 at 5 K. The presented results show an excellent agreement with former measurements above 30 K including a value of d n / d T = 1.8 × 10 -4 K -1 at 300 K. © 2012 American Institute of Physics.