摘要 |
A wavelength stabilizing unit includes a wavelength filter 31 and an optical detector 4, which are mounted on a substrate 71, and housed in a casing 91. The optical detector 4 includes a first photoelectric conversion element 5, which directly receives an emitted light from an end portion (emitting point 58) of an optical fiber 14 guided into the casing 91 and converts it into an electric signal A, and a second photoelectric conversion element 6, which receives light passed through the wavelength filter 31 and converts it into an electric signal B. The electric signals A and B are supplied to an operation circuit 8. The wavelength filter 31 has side faces, which are machined such that they do not cross a straight line connecting the emitting point 58 and an edge of an incident surface 311 of the wavelength filter.
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