Proposal of small-aperture guided-mode resonance filter

A guided-mode-resonance filter (GMRF) consisting of a thin film waveguide and a surface periodic relief has been widely studied for application to a laser mirror as well as to an optical wavelength filter, because of its great advantage in mass production in comparison to multilayer dielectric mirrors. However, GMRF needs some considerably large coupling area to provide high coupling efficiency, meaning that the direct coupling to an optical fiber or a semiconductor laser end is difficult. Therefore, the miniaturization of GMRF is very attractive in practical applications. In this paper, we propose a new concept of the integration of a cavity resonator consisting of a pair of distributed Bragg reflectors to miniaturize a GMRF aperture down to several micrometers matching to the electric-field size of an optical fiber or a semiconductor laser.