Design of unidirectional erbium-doped waveguide ring laser with asymmetric distributed Bragg grating

Proposed is the employment of a second-order asymmetric Bragg grating as an intra-cavity element enabling unidirectional operation of integrated ring lasers. This idea is examined by means of numerical simulations for the case of erbium-doped silica-on-silicon waveguide ring lasers. It is shown that suppression of lasing in one direction can be designed to achieve 20 dB.