| 摘要 |
PURPOSE:To enable the stable single lateral mode oscillation by preventing fluctuation of laser beams by forming a light waveguide in a direction parallel to periodical stripe-form unevenness. CONSTITUTION:A coupling waveguide is formed by the difference of refractive index between an active layer 4 and an upper cladding layer 5a adjacent to said layer 4, and between a light guiding layer 3a and a lower cladding layer 2a adjacent to said layer 3a, and current constriction and absorption of light by a current block layer 6, which guides the light generated from the active layer 4. In this waveguide, a periodical distribution of refractive index is formed in a direction parallel to the active layer 4, namely in lateral direction by the stripe-form unevenness formed periodically on the upper part of a substrate 1a. As a result, a high-order mode is cut off and oscillation only by a basic mode becomes possible. Also, there is almost no variation of a refractive index due to an increase of an injected current and fluctuation of laser beams is prevented.
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