Hamamatsu-photonics K.k.

Takahide Ochiai

Naota Akikusa

Tadataka Edamura

Atsushi Sugiyama

Kazuue Fujita

Hirofumi Kan

Tatsuo Dougakiuchi

Kousuke Shibata

Shinichi Furuta

A quantum cascade laser device includes a QCL element; a lens; and a lens holder having a small-diameter hole, a large-diameter hole, and a counterbore surface. At least a part of a side surface of the lens is fixed to an inner surface of the large-diameter hole in a state where an edge portion of an incident surface of the lens is in contact with the counterbore surface. A central axis of the small-diameter hole is eccentric from that of the large-diameter hole. The side surface of the lens is positioned with respect to the inner surface of the large-diameter hole along a direction from the central axis of the large-diameter hole toward the central axis of the small-diameter hole. A central axis of the lens is disposed at a position closer to the central axis of the small-diameter hole than to the central axis of the large-diameter hole.

Quantum cascade laser device

The laser module includes a QCL element, a MEMS diffraction grating, a lens holder for holding a lens disposed between the QCL element and the MEMS diffraction grating, and a package. The package includes a bottom wall, a side wall erected on the bottom wall and formed in an annular shape so as to surround a region in which the QCL element is accommodated, and a top wall closing an opening of the side wall on a side opposite to a side where the bottom wall is disposed. The top wall faces the bottom wall in a direction orthogonal to the optical axis direction of the lens, and the distance between the top wall and a surface of the lens holder on a side where the top wall is disposed is smaller than a thickness of the lens holder along the optical axis direction of the lens.

External resonant laser module

The laser module includes a QCL element, a MEMS diffraction grating, a lens holder holding a lens disposed between the QCL element and the MEMS diffraction grating, a package, an electrode terminal disposed along an inner wall surface of the package, and a wire for electrically connecting the electrode terminal and a coil. The top wall of the package faces the bottom wall of the package in a direction orthogonal to the optical axis direction of the lens. The MEMS diffraction grating includes an electrode pad electrically connected to the coil. The electrode pad is connected to the electrode terminal via the wire. A height position of the electrode pad with respect to the bottom wall is equal to or higher than a height position of the electrode terminal with respect to the bottom wall.

A light source module includes a light source; an optical fiber configured to guide light output from the light source; a pair of holding members configured to hold both ends of a first portion of the optical fiber such that the first portion extends linearly; a first vibrator configured to vibrate the first portion along a first direction intersecting an extending direction of the first portion; and a second vibrator configured to vibrate the first portion along a second direction intersecting the extending direction and differing from the first direction.

Light source module

A quantum cascade laser device has a light-absorbing cover member located between one emission end face of a quantum cascade laser element and an emission window of a housing. The emission end face and an opposing surface of a submount with respect to the cover member are flush with each other. The cover member has an opening at a position opposing the emission end face. The opening has a tapered first opening part increasing its diameter from the emission end face side to the emission window side and a second opening part formed with a fixed diameter not smaller than the smallest diameter of the first opening part.

A laser module LM is provided with a quantum cascade laser, a tubular member, and an infrared detector. The tubular memberhas a pair of opening endsand is arranged so that one opening endis opposed to a faceopposed to an emitting end faceof the quantum cascade laser. The infrared detectoris arranged so as to be opposed to the other opening endof the tubular member. Light emitted from the face (rear end face)opposed to the emitting end face (front end face)of the quantum cascade laseris guided inside the tubular memberto enter the infrared detector, and then is detected.

Laser module

A DFB quantum cascade laser element that can reliably CW-oscillate a single-mode light even at room temperature or a temperature in proximity thereof is provided. In a quantum cascade laser element, a top-grating approach for which a diffraction gratingis formed on a laminateis adopted, and thus in comparison with a buried-grating approach, deterioration in temperature characteristics of the laser element and decline in the yield and reproducibility are suppressed. In addition, since the thickness of a cladding layerlocated between an active layerand the diffraction gratingis within a range of 42&#xb1;10% of the oscillation wavelength, weakening of light seeping from the active layerto the diffraction gratingor an increase in light leakage is prevented. Consequently, by the quantum cascade laser element, a single-mode light can be reliably CW-oscillated even at room temperature or a temperature in proximity thereof.

Quantum cascade laser element

A quantum cascade laser includes a semiconductor substrate, and an active layer which is provided on the semiconductor substrate, and has a cascade structure in which unit laminate structureshaving quantum well emission layersand injection layersare laminated in multiple stages. Further, the quantum cascade laser is configured such that the unit laminate structurehas an emission upper level L, an emission lower level L, and a relaxation miniband MB including an energy level lower than the emission lower level in its subband level structure, and light is generated by an intersubband transition of electrons from the upper level to the lower level, and the electrons after the intersubband transition are relaxed from the lower level Lto the miniband MB through LO phonon scattering, to be injected from the injection layerto the latter stage emission layer via the miniband MB. Thereby, the quantum cascade laser which is capable of efficiently forming an inverted population in the quantum well emission layer, to improve its laser operation performance, is realized.

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Hamamatsu, Japan

Takahide Ochiai