Abstract: The invention relates to a method of implementation of surface-emission laser diodes with multiple quantum wells, including a single epitaxy step and a single step of implantation and diffusion of doping impurities. The transverse dimensions of the laser are determined by application of a mask on the active region before the implantation of said doping impurities around said active region, thus avoiding the conventional step of chemical etching with its detrimental effects on the expected lifetime of the finished laser. The construction of the laser of the invention allows to optimize separately the characteristics of optical confinement (along the axis of propagation of the laser light) and of confinement of the charge carriers in said active region (perpendicularly to said axis of propagation).

Abstract: A rib waveguide polarization modulator is described that permits easy application to monolithic optical circuits. The device comprises a rib waveguide having two polarization modulation sections with a phasing section between the two modulation section. The phasing section adjusts the phase of the optical radiation in the waveguide before it enters the second modulation section.

Abstract: An optical polarizer is described in which a propagation layer (14) is covered with a dielectric buffer layer (16) and a metal layer (18). The thickness of the buffer layer is chosen so as to increase the attenuation of TM modes of radiation in the waveguide relative to TE modes. In accordance with the invention, additional discrimination between TM and TE modes is achieved by segmenting the metal layer into a plurality of tandem sections (18.1, 18.2, 18.3), thereby increasing the mode coupling loss for TM modes. A GaAs-AlGaAs rib waveguide polarizer is specifically described.