摘要 |
A semiconductor optical amplifier includes a semiconductor substrate; an active layer that includes a first region and a second region formed over the semiconductor substrate; and a reflection part that is formed along the second region and includes a first portion that reflects a first wavelength light and a second portion that reflects a second wavelength light with an optical gain lower than an optical gain of the first wavelength light; wherein, the first portion is formed closer to the first region side than the second portion.
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