Design of Fabry-Perot filters in planar waveguides with deep-etched features for spatial switching

Scalable optical space switches compatible with high bit rates which can be reconfigured on-the-fly are needed to increase the flexibility of optical networks. We present the design of integrated Fabry-Perot filters working at oblique incidence, which can be used to build optical space switches. A comprehensive planar waveguide optimization was conducted to minimize radiation losses in the deep-etch features forming the filter mirrors. Four high order cavities were coupled to create a 200 GHz comb wavelength response with passbands larger than 50 GHz and extinction ratio greater than 20 dB over the entire C-band. Gaussian beam propagation analysis showed that the minimum beam waist required to avoid distortion increases rapidly with incident angle.