Patent ID: 8395765
Filing Date: 2013-03-12
Classification: H01S

Abstract:
1. A wavelength monitor that monitors a wavelength of laser light emitted from at least two semiconductor lasers formed in parallel on a semiconductor substrate; comprising: a lens that collimates laser light from each of the semiconductor lasers; a filter that is arranged so that laser light collimated by the lens is capable of entering and has a periodicity; and a photodetector that receives laser light transmitted through the filter and detects a light intensity, wherein an intra-filter beam propagation angle of laser light emitted from each of the semiconductor lasers becomes a predetermined angle obtained by the following formula: where f indicates an arbitrary peak frequency, m k indicates an order of interference which is an arbitrary natural number for each k, c indicates a light speed, n λ indicates a refractive index of the filter at a wavelength λ, L etalon indicates a length of the filter, and θ k indicates an intra-filter beam propagation angle (rad) of laser light emitted from a k-th semiconductor laser.