DEVICE FOR STABILIZING OPTICAL FILTER BY WAVELENGTH AND ITS OPERATION

摘要

PROBLEM TO BE SOLVED: To stabilize an optical filter locally by a reference wavelength by arranging a Brugg grating capable of supplying a prescribed fixed light reference wavelength near the filter. SOLUTION: The optical filter 1 is formed on a surface 100 of a substrate 10. The Brugg grating 2 capable of supplying the prescribed light reference wavelength 20 is arranged near the filter 1. The wavelength transmission characteristic of the Brugg grating 2 related to reflection and/or transmission for the reference wavelengthλ0 is used without depending on a wavelength transmitted through the filter 1. The reference wavelengthλ0 is supplied into an optical fiber 21 to be made incident on an integrated waveguide 20. The reflection part of the reference wavelength reflected by the Brugg grating 2 of the reference wavelengthλ0 is supplied to a photodetector through the optical fiber 21. The transmission part transmitting through the Brugg grating 2 of the reference wavelength 20 is supplied to the photodetector through the optical fiber 22 connected to the integrated waveguide 20.