摘要 |
In order to realize an optical semiconductor device having a window structure promising high-speed operation and highly efficient coupling with optical fibers and to realize its manufacturing method, the device has a window structure in which an optical guide layer is partly removed near the emission facet to decrease the facet reflectivity. Since a cladding layer has a narrow mesa structure also in a window region, the parasitic capacitance can be reduced, and high-speed modulation is ensured. Although light runs through the window region in spread directions from one end of the optical guide layer toward the emission facet, the cladding layer changes its width or thickness in accordance with the spread angle of light. Therefore, light is not reflected or scattered by side surfaces of the cladding layer, and prevents a decrease in optical output due to a scattering loss, or a deterioration in distribution of emitted light. As a result, the device has a high coupling efficiency with optical fibers, and is operative for high optical output.
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