Single Wavelength Resonator Based on π Phase-shifted Antisymmetric Bragg Grating

The principle, design and characterization of a resonator on the silicon-on-insulator (SOI) platform based on the π phase-shifted antisymmetric Bragg grating (ASBG) are presented. With the aid of an asymmetric directional coupler (ADC), the resonance circuit between the two ASBGs is formed by the forward first order transverse electric (TE1) mode and the backward fundamental transverse electric (TE0) mode. Only negligible amount of the backward TE0 mode can be coupled to the bus waveguide, which is different from the conventional Fabry-Perot (F-P) resonator. Compared with the widely used microring resonator, it can realize single wavelength resonance. The single resonance resonator with an extinction ratio of 20.0 dB and a quality factor (Q-factor) of 9888 has been experimentally demonstrated. Moreover, multiple wavelength resonances with free spectrum range (FSR) of 0.63 nm is obtained when the phase shifter length is 200 μm.