Semiconductor laser device and method for manufacturing semiconductor laser device

A semiconductor laser device comprising:

• a semiconductor substrate;
• a resonator unit formed on the semiconductor substrate and having an active layer, a diffraction grating formed on or underneath the active layer, a front facet of a forward mesa slope, and a rear facet, wherein a length in a resonator direction is shorter than a length in the resonator direction of the semiconductor substrate;
• an anti-reflection coating film formed on the front facet;
• a reflective film formed on the rear facet;
• a metal mirror provided on the semiconductor substrate;
• an upper electrode formed on the resonator unit;
• a lower electrode formed underneath the semiconductor substrate, and
• a dielectric material formed on an opposite side of the front facet of the resonator unit from the resonator unit in the resonator direction in a portion of an upper surface of the semiconductor substrate where the resonator unit is not formed,
• wherein the metal mirror is configured to reflect a laser beam emitted from the front facet.

A manufacturing method of a semiconductor laser device comprising:

• forming a mask on a semiconductor substrate;
• selectively growing a semiconductor layer on a portion of the semiconductor substrate not covered with the mask and forming a resonator unit having a diffraction grating and a front facet defining a slope;
• forming an upper electrode on an upper surface of the resonator unit and forming a lower electrode on a lower surface of the semiconductor substrate;
• forming an anti-reflection coating film on the front facet and forming a reflective film on a rear facet of the resonator unit;
• and
• forming a dielectric material on an opposite side of the front facet of the resonator unit from the resonator unit in the resonator direction in a portion of an upper surface of the semiconductor substrate where the resonator unit is not formed,
• wherein
• a length in a resonator direction of the resonator unit is shorter than a length in the resonator direction of the semiconductor substrate.

A manufacturing method of a semiconductor laser device comprising:

• growing a semiconductor layer on a semiconductor substrate to form a resonator unit having a diffraction grating;
• forming a mask on a part of the resonator unit;
• performing anisotropic etching with etchant on a portion of the resonator unit not covered with the mask and shaping a front facet of the resonator unit into a slope;
• forming an upper electrode on an upper surface of the resonator unit and forming a lower electrode on a lower surface of the semiconductor substrate;
• forming an anti-reflection coating film on the front facet and forming a reflective film on a rear facet of the resonator unit, and
• forming a dielectric material on an opposite side of the front facet of the resonator unit from the resonator unit in the resonator direction in a portion of an upper surface of the semiconductor substrate where the resonator unit is not formed, wherein
• a length in a resonator direction of the resonator unit is shorter than a length in the resonator direction of the semiconductor substrate.