Multiple-reflector lasers for photonic integrations

For photonic integration of many lasers and electro-optic devices on a single chip, high quality deep etching technology is one of the promising key technologies. For this purpose, new types of lasers consisting of semiconductor/air mirrors and semiconductor/polymer buried groove mirrors, such as multiple-micro-cavity (MMC) lasers and distributed Bragg reflector (DBR) lasers have been investigated. We proposed the use of a low-loss polymer embedded in the DBR structure, which acts as a high reflective multiple reflector on one side of the laser, for a reduction of the diffraction loss and the construction of robust DBR lasers. The reflectivity of 3λ/4-semiconductor/benzocyclobutene (BCB) DBR GaInAsP/InP lasers with emission at 1.55 pm wavelength was measured to be >90% from their threshold dependence on the cavity length and the ratio of output powers from the cleaved (front) and the DBR (rear) facets. The BCB polymer is recently a very attractive material for numerous passive opto-electronic devices such as optical waveguides, filters, matrix switches, spot-size converters, and so on. We review the fabrication and lasing characteristics of such deeply etched DBR lasers, and present new types of single-mode lasers consisting of a coupled-cavity and DFB/DBR structures