| 摘要 |
PURPOSE:To form output light in a regularly circular and parallel beam without using an outer lens and an outer lattice by providing a concentrically circular grating region on the periphery of an active region so that light emitting face becomes symmetrical with respect to an active region. CONSTITUTION:An active region 2 which becomes a light emission source is provided on a compound semiconductor single crystalline substrate 1. A hetero junction can be formed by an MOCVD method or a liquid phase epitaxy method by the active region. The active region is formed in a circular state, and electrodes 4 are formed on the upper face of the active region and the rear face of the substrate. A grating pattern is formed, for example, by a reverse sputtering method on the periphery of the active region. The light emitted from the active region generates strong diffracted light toward the upper face of the substrate in a grating region 3. The lattice interval is so set that the diffracted light is diffracted in the perpendicular direction to the upper face of the substrate in response to the wavelength lambda of the laser radiation to obtain a round laser beam.
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