Wavelength monitor apparatus and wavelength stabilizing light source

Abstract

In a wavelength monitor apparatus, a wavelength filter whose wavelength transmission property continuously changes in accordance with an incidence angle is disposed on a laser light axis, and a transmitted light of the wavelength filter is optically connected to a light receiving element. The wavelength filter is vibrated by a piezoelectric element, and the incidence angle is slightly vibrated. An output signal from a light emitting element is supplied to a lock-in amplifier, and the lock-in amplifier uses a drive signal of the piezoelectric element as a reference signal and monitors a frequency of the output signal. A signal from the lock-in amplifier is supplied to a drive controller, and a wavelength of the light emitting element is adjusted.

Dependencies are inferred from the claim text.