Cavity-Resonator-Integrated Guided-Mode Resonance Filter with Nonuniform Grating Coupler for Efficient Coupling with Gaussian Beam

A cavity-resonator-integrated guided-mode resonance filter (CRIGF) has been proposed and investigated for providing a high-efficiency narrowband reflection with a small aperture. The CRIGF consists of a grating coupler (GC) and a pair of distributed Bragg reflectors (DBRs) constructing a waveguide cavity resonator. This time, a GC with nonuniform fill factors was integrated in a channel waveguide resonator in order to realize efficient coupling with an incident Gaussian beam of about 10 mu m diameter. The improvement of reflection efficiency was confirmed by numerical simulations as well as experimental results with the fabricated device for 1.55-mu m-band operation. (c) 2013 The Japan Society of Applied Physics