WAVELENGTH MONITOR, WAVELENGTH-STABILIZED LIGHT SOURCE USING THE SAME, AND METHOD OF DETECTING WAVELENGTH

摘要

PROBLEM TO BE SOLVED: To reduce the number of optical components, and to facilitate adjustment for an optical axis, in a wavelength monitor. SOLUTION: A wavelength filter 1 of which the wavelength transmission characteristic is continuously changed by an incident angle is arranged on the optical axis of a laser beam, and transmission light of the wavelength filter is optically coupled to a photoreceiving element 3. The filter 1 is vibrated by a piezoelectric element 2 to vibrate finely the incident angle. An output signal from a luminescent element 8 is supplied to a lock-in amplifier 6, and a frequency of the output signal is monitored using a drive signal of the piezoelectric element 2 as a reference signal in the lock-in amplifier 6. A signal from the amplifier 6 is supplied to a drive control signal 9 to regulate a wavelength of the luminescent element 8.