| 摘要 |
PURPOSE: To make the detuning amount of each element equal, and make the oscillation wave amplitude large, by a method wherein a laser active layer is formed by growing an optical guide layer so as to fill a diffraction grating, and performing selective growth on the guide layer, by using a mask for selective growth wherein the mask width is different between adjacent elements. CONSTITUTION: A diffraction grating 2 is formed on an N-type InP substrate 1. An InGaAsP layer 3 is buried in the whole part of the substrate where the diffraction grating 2 is formed, and turned into an optical guide layer. Thereon a mask 4 for selective growth is formed which is to be used for forming an active layer stripe. The mask 4 is so formed that the width is incremented 10μm in 10-40μm range between neighboring active layer stripes. By performing selective growth using the mask 4, the lower side SCH layer is sequentially grown and active layer stripes for 4 channels are formed just above the buried diffraction grating. After that, unnecessary parts 6 and the mask 4 for growth are eliminated, and a current blocking layer 7 is formed.
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