Distributed Feedback Semiconductor Laser Device

Abstract

A DFB laser device which can reduce influence of reflected return light and improve output characteristics and can provide a small-sized and inexpensive optical module when mounted on the optical module. The GC-DFB laser device (10) includes a semiconductor substrate (100), a waveguide layer (104) and an active layer (106) formed on one surface side of the semiconductor substrate, and a diffraction grating structure (102) which is formed on one surface of the waveguide layer and has a gain periodically varying in an optical waveguiding direction; wherein the active layer is disposed so as to adjoin the waveguide layer, a band gap wavelength of the waveguide layer is within ±0.1 μm of an oscillation wavelength of the active layer, a thickness of the waveguide layer is in a range of 5 to 30 nm, and a width of the active layer is in a range of 0.7 to 1.0 μm.

Dependencies are inferred from the claim text.