Patent ID: 7656911
Filing Date: 2010-02-02
Classification: H01S

Abstract:
1. An external resonator type wavelength-variable laser capable of varying a wavelength within a range Δf comprising: a semiconductor light amplifier; a wavelength selection filter having periodic frequency characteristics; and a wavelength-variable filter, wherein the laser is configured so that the range Δf is divided into one or more regions, and regarding at least one region Δf a coefficient m where Δf Δf j: an integer not smaller than 1 and not larger than (Δf a coefficient M a coefficient N and then relations of (M wherein the j=2; and the wavelength selection filter transmits a plurality of wavelength transmission bands including: a first wavelength transmission band having a center frequency matching a first frequency of a Fabry-Perot mode; and a second wavelength transmission band being directly adjacent to the first wavelength transmission band and having a center frequency with a phase difference of about π with respect to a second frequency of the Fabry-Perot mode.