OPTICAL DEVICE HAVING UNIDIRECTIONAL MICRORING RESONATOR LASER CAPABLE OF SINGLE-MODE OPERATION

Examples described herein relate to an optical device. The optical device includes a first microring resonator (MRR) laser having a first resonant frequency and a first free spectral range (FSR). The first FSR is greater than a channel spacing of the optical device. Further, the optical device includes a first frequency-dependent filter formed along a portion of the first MRR laser via a common bus waveguide to attenuate one or more frequencies different from the first resonant frequency. A length of the common bus waveguide is chosen to achieve a second FSR of the common bus waveguide to be substantially equal to the channel spacing to enable a single-mode operation for the optical device. Moreover, the optical device includes a first reflector formed at a first end of the common bus waveguide to enhance a unidirectionality of optical signal within the first MRR laser.