摘要 |
Composition wavelengths of materials of cladding layers and optical guide layers are 0.92 mum and 1.2 mum respectively. When the thickness of optical guide layers, corresponding to an extreme value in which inclination of a sensitivity curve to 1.3 mum-wavelength light and to 1.55 mum-wavelength light with respect to a change in the thickness of each of both optical guide layers changes from positive to negative, are defined as d1 and d2, respectively, the thickness, dg, of optical guide layers of a light detecting element satisfies 0.75d1<=DG&LE;1.25D2.
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