INTEGRATED GRATING OUTPUT COUPLER IN DIODE LASERS

摘要

INTEGRATED GRATING OUTPUT COUPLER IN DIODE LASERS A heterojunction diode laser which produces a highly collimated, polarized light beam perpendicular to the plane of the PN junction of the laser rather than through cleaved end faces in the plane of the PN junction. The diode laser includes a periodic structure which is buried at a heterojunction interface and in contact with a light waveguide layer. The periodic structure acts to produce the feedback necessary for lasing. If the spacing of the teeth of the periodic structure are an integer number of wavelengths of the light photons produced in the laser, the light beam exits at an angle perpendicular to the plane of the PN junction. If a tooth spacing is chosen that is not equal to an integer number of wavelengths of the light photons produced in the laser, the light beam may emerge from the diode at an angle other than the normal with the specific angle determined by the particular tooth spacing. To increase output intensity, the ends of the laser perpendicular to the plane of the PN junction and parallel to the teeth of the periodic structure may be cleaved and coated with a highly light reflective film.