Design and characterization of microring reflectors with a waveguide crossing

We present a novel design of a wavelength-selective reflector using a microring resonator integrated with a low-loss, low-crosstalk waveguide crossing. Functioning as a reflective notch filter, it can be used for optical communications and for sensor applications. The device is simulated using the transfer-matrix method combined with a two-dimensional finite-difference mode solver and is fabricated by a CMOS-compatible silicon-on-insulator technology. The measurement shows an extinction ratio greater than 25 dB and a resonance-wavelength temperature dependence of 0.09 nm/K.