TDFA-BAND SILICON OPTICAL VARIABLE ATTENUATOR

|TDFA-band (2- (cid:22) m waveband) has been considered as a promising optical window for the next generation of optical communication and computing. Absorption modulation, one of the fundamental recon(cid:12)gurable manipulations, is essential for large scale photonic integrated circuits. However, few efforts have been involved in exploring absorption modulation at TDFA-band. In this work, variable optical attenuators (VOAs) for TDFA-band wavelengths were designed and fabricated based on a silicon-on-insulator (SOI) platform. By embedding a short PIN junction length of 200 (cid:22) m into the waveguide, the fabricated VOA exhibits a high modulation depth of 40.49 dB at 2.2 V and has a fast response time (10 ns) induced by the plasma dispersion effect. Combining the Fabry-Perot cavity effect and plasma dispersion effect of silicon, the attenuator could achieve a maximum attenuation of more than 50 dB. These results promote the 2- (cid:22) m waveband silicon photonic integration and are expected to the future use of photonic attenuators in crosstalk suppression, optical modulation, and optical channel equalization.