JPS58199587A - Oscillation controller for semiconductor laser - Google Patents

Abstract

PURPOSE:To obtain an optical system which does not vary oscillating wavelength even if the position of a laser is altered by introducing the light of a semiconductor laser incident to a dispersion optical system and a reflection optical system. CONSTITUTION:The light emitted from one end face of a semiconductor laser 1 becomes parallel light rays via an optical lens 3, incident to a dispersion optical system which is formed of a plane diffraction grating 5 and a reflecting surface 6 perpendicularly crossed with the normal in parallel with the etching direction of the grating 5, and the reflected parallel light rays are fed back to the laser 1. The light emitted from the other end face of the laser 1 is incident to a cat's eye which is formed of a lens 4 and a mirror 7, and the reflected light is returned to the laser 1. Similar operation is performed in a semiconductor laser 2. Equal wavelength lines exit in X-Y plane surface of focal point, and when two lasers are disposed on the same equal wavelength line, they oscillate with the same wavelength.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor laser oscillation control device. A dispersion optical system in which a semiconductor laser beam is directed to a plane diffraction grating and a plane reflection surface are orthogonal to each other so that the direction of the score lines and the normal to the plane reflection surface are parallel, or a plane or concave surface is placed on the focal plane of the diffraction grating dispersion optical system. The dispersion optical system uses a dispersion optical system to reflect the dispersed light and disperse it again using a diffraction grating dispersion optical system, and then returns it to the semiconductor laser. By doing so, multiple semiconductor lasers can be combined without crosstalk between the oscillated light. The oscillation wavelength can be fixed to an arbitrary value, but in this method, the resonator is constructed of a dispersive optical system and a reflecting surface at one end of the semiconductor laser, so the position of the individual semiconductor lasers does not change due to mutual vibration etc. Affects the difference in oscillation wavelength of multiple semiconductor lasers.

Therefore, the light controlled by the method described above is unsuitable as a light source for precise optical heterodyne measurement.

The present invention relates to an oscillation control optical system in which the oscillation wavelength difference does not change even if a slight change in position occurs in a semiconductor laser. As a new light source, it offers new possibilities in the optical communication field, optical measurement field, and other fields.

The details of the present invention will be explained below with reference to the drawings.

FIG. 1 shows an embodiment of the invention. In FIG. 1, the light emitted from one end face of the semiconductor laser 1 is converted into a parallel beam by the lens 3, and the plane diffraction grating 5 and the reflecting surface are made orthogonal so that the normal line is parallel to the groove direction of the plane diffraction grating 5. Parallel rays incident on the dispersion optical system consisting of 6, diffracted and reflected are accurately returned to the semiconductor laser 1 by the lens 3. In addition, the light emitted from the other end face of the semiconductor laser 1 enters the lens 4 and the cat's eye made up of the conjugate point of the lens 4 (the mirror 7 that is placed), and the reflected light is reflected by the semiconductor laser 1.
is accurately fed back to the other end face of the semiconductor laser 1, and the oscillation wavelength of the semiconductor laser 1 is controlled. The same applies to the semiconductor laser 2, and by adjusting the mutual positions of the semiconductor lasers 1 and 2, the oscillation wavelength difference can be selected to an arbitrary value. That is, in this optical system, the wavelength of the returned light is determined by two parameters, the off-Braino angle and the inno-Braino angle of the incident light on the diffraction grating 5. Therefore, in the focal plane x-y plane, the equiwavelength line 30
exists. Therefore, if two semiconductor lasers are placed on the same equiwavelength line, they will oscillate at the same wavelength, and if they are placed on a line that is inclined to the equiwavelength line, they will oscillate at different wavelengths. be able to. In this optical system, the resonator is made up of an optical system other than the semiconductor laser, so even if the position of the semiconductor laser changes slightly, the effect on the oscillation is small, and two or more resonators are used in a common resonator. Since the semiconductor laser oscillation conditions are determined as described above, the oscillation wavelength difference becomes extremely stable.

FIG. 3 shows another embodiment. The light emitted from one end face of the semiconductor laser 1 becomes a parallel beam by the lens 3, is diffracted by the plane diffraction grating 8, and the spectrum is imaged by the lens 20.

A reflecting mirror 10 having a small diameter is placed at the imaging point, and the reflected light enters the plane diffraction grating 8 again. The re-diffracted light becomes non-dispersive light and is accurately fed back to the semiconductor laser 1. Further, the light emitted from the other end face of the semiconductor laser is converted into a parallel beam by the lens 4, reflected by the triangular roof mirror 9, and accurately returned to the semiconductor laser 1. The oscillation wavelength and the oscillation wavelength can be changed depending on the direction (within the focal plane) in which the mirror having a microscopic center and the semiconductor laser 1.2 are arranged.

The embodiment shown in FIG. 4 is an example in which the lens 3 and the lens 20 are common. In the figure, semiconductor laser 1.
The mirrors 10 and 11 having the mirrors 2 and 1] are placed on the inbrain, but it is more realistic to arrange them on the off-brain. In addition, in this embodiment, the concave mirror 14 and the reflecting mirror 12, ]3
This constitutes an optical system that creates an erect image.

In the embodiment shown in FIG. 5, a concave diffraction grating is used instead of a plane grating.

Although some examples of a dispersive optical system and an erect image reflective optical system have been given, the combination of the two is arbitrary. In addition, almost all optical paths can be made of transparent dielectric material, and the optical system can be solidified.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the invention, FIG. 2 is a detailed explanatory diagram of the invention, and FIGS. 3, 4, and 5 show other embodiments of the invention. 1.2... Semiconductor laser 3.4... Lens 5... Planar diffraction grating 6... Planar reflective surface 7 - Reflective surface xvy... ...Coordinate axis 8 ... Plane diffraction grating 9 ... Triangular roof-shaped reflecting mirror 10.11.12.13 ... ... Reflection surface 14 with microscopic holes ... Concave reflection Surface 15...Concave diffraction grating 30...
・Equiwavelength ray I (￥J peak z(9 忰 41 sides 429

Claims (1)

[Claims] Dispersion of light emitted from one end face of a plurality of semiconductor lasers that emit light from both end faces, with a plane diffraction grating and a plane reflection surface perpendicular to each other so that the normal line is parallel to the groove direction of the plane grating. A flat or concave micromirror is placed on the focal plane where the spectrum of an optical system or a concave or flat diffraction grating dispersion optical system is generated to reflect the dispersed spectrum, and the concave or flat diffraction grating dispersion is reflected dispersively or additively. A reflective optical system that makes the diffracted light incident on the optical system return to one end face of the semiconductor laser and that emits the light emitted from the other end face of the semiconductor laser into an erect image such as a cat's eye or a triangular roof mirror. A semiconductor laser oscillation control device characterized in that the semiconductor laser is reflected and returned to the other end face of the semiconductor laser to cause a plurality of semiconductor lasers to oscillate at the same arbitrary wavelength or different wavelengths.