Wavelength monitoring device and its adjusting method, and wavelength stabilizing light source and transmission system having plural wavelength stabilizing light source

摘要

A wavelength monitoring device comprising: a polarization state changing means having a first birefringent crystal, which inputs a polarized laser light and changes the polarization state of the input laser light after it is transmitted through the first birefringent crystal, in accordance with the wavelength of the input laser light, a polarized light selecting and receiving means, which inputs the laser light transmitted through the polarization state changing means and selectively receives a predetermined linearly polarized component, and a wavelength detection means for monitoring the wavelength of the laser light input to the first birefringent crystal by use of an optical signal output from the polarized light selecting and receiving means.