POLARIZATION MODULATING LASER DEVICE

摘要

A polarization modulation laser device which outputs a laser beam having stable output intensity on a low-threshold current with high efficiency and can be easily fabricated . The polarization modulation laser device comprises a quantum line absorption modulation layer (4) (first polarization control structure) for fixing the polarization direction of the laser beam to a first polarization direction by means of electrical means and a rectangular post structure (second polarization control structure) for controlling the polarization direction of the laser beam to a direction other than the first polarization direction. The quantum line absorption modulation layer (4) includes an absorption modulation structure for varying the light absorption coefficient to the laser beam by means of electrical means. The quantum line absorption modulation layer (4) has an anisotropic light absorption coefficient in the plane perpendicular to the output direction of the laser beam of the absorption modulation structure. In the polarization modulating laser device, the absorption modulation structure of the quantum line absorption modulation layer (4) is electrically isolated form the quantum well active layer (9) (layer containing a gain medium).