High-speed optical sensor interrogator with a silicon-ring-resonator-based thermally tunable filter

Abstract

On-chip optical interrogators employing a silicon-ring-resonator-based thermally tunable filter (SRRTF) offer a promising solution for realizing portable, compact optical sensing systems. However, the slow interrogation speed of conventional SRRTF-based interrogators (less than a few Hz) hinders real-time sensing of dynamic parameters. In this Letter, we report a 100 kHz of high-speed optical interrogation system based on the SRRTF. The speed enhancement is achieved by using the nonlinear transient response of the SRRTF to a square-wave input voltage. The entire spectral range of the SRRTF is scanned twice during its thermal response cycle. The time-domain sensor output signal, which is obtained by scanning the SRRTF over the sensor spectrum, is converted into spectrum domain based on the experimentally characterized, time-dependent resonance wavelength shifts of the SRRTF. With this system, we demonstrate high-speed interrogation of a fiber Bragg grating sensor under dynamic temperature change (200 Hz).