We experimentally demonstrate tunable silicon comb filters based on Fabry–Perot (FP) resonators composed of two Sagnac loop mirrors. The comb filter resolves up to 54 comb lines with a 115 GHz channel spacing over a spectral range from 1510 to 1560 nm. The comb line extinction ratio is ∼26.3 dB and the quality factor is ∼57,000 around 1550 nm wavelength. Electrical tuning is enabled via periodically interleaved PN junctions embedded inside the FP resonator. The comb lines are blue shifted by ∼0.92 nm (one channel spacing) with a 5 mA forward-bias current and red-shifted by ∼0.05 nm with a −10 V reverse-bias voltage.
© 2013 Optical Society of America
Original Manuscript: November 28, 2012
Revised Manuscript: January 11, 2013
Manuscript Accepted: January 21, 2013
Published: February 13, 2013
Xiaomeng Sun, Linjie Zhou, Jingya Xie, Zhi Zou, Liangjun Lu, Haike Zhu, Xinwan Li, and Jianping Chen, "Tunable silicon Fabry–Perot comb filters formed by Sagnac loop mirrors," Opt. Lett. 38, 567-569 (2013)