Patent ID: 8189631
Filing Date: 2012-05-29
Classification: H01S

Abstract:
1. An external resonator-type wavelength tunable laser device including at least a planar reflection structure enabling a reflection spectral peak wavelength to be varied, and a semiconductor gain medium, wherein the external resonator-type wavelength tunable laser device contains the semiconductor gain medium comprising a multiple quantum well in which, when reflectance difference ΔR (dB) of the planar reflection structure is defined by ΔR=10·log (R product Γ·L of optical confinement constant Γ and semiconductor gain medium region length L (μm) of a gain layer in the semiconductor gain medium is at least 25 μm and at most 40 μm, and gain peak wavelength λ wherein the internal loss of the semiconductor gain medium is a loss of optical power absorbed at an inside of an active layer of the semiconductor gain medium, the gain peak wavelength λ