JPS6026319B2 - solid state laser device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compact solid-state laser device that can emit coherent laser light with a small divergence angle and simultaneously modulate the light intensity.

Recently, the importance of optical communications has been rapidly increasing, and the light source is the most important component. A conventional compact solid-state laser and modulator device is shown in FIG.

In FIG. 1, 1 indicates a laser oscillation section and a D'ma modulation section, and a laser active soot substance 1 is a light emitting diode 2.
It is excited by the light that is generated and passed through the condenser lens 3. Both ends of the laser active soot material 1 are spherical surfaces with a certain curvature, and are coated with reflective films 4 and 5. The reflective films 4 and 5 at both ends constitute an optical resonator, and amplification is performed inside the resonator, and laser light is emitted to the right of the laser-activated soot material 1 in the figure. The emitted light passes through a polarizer 6, is linearly polarized, enters a modulator 7 made of a crystal with an electro-optic effect, and then enters an analyzer 8. The polarizer 6 and the analyzer 8 are arranged so that their polarization directions are perpendicular to each other. The light exiting the analyzer 8 becomes an optical signal modulated by the voltage applied to the modulator 7. Since the subordinate solid-state laser and modulator device are constructed as described above, the laser oscillation section 1 and the modulation section 0 are constructed separately, and optical adjustment of each is delicate and difficult.

Furthermore, since the end face of the laser active medium 1 is a spherical surface with curvature, it is difficult to integrate it with the polarizer 6 on a flat plate. This invention was made in order to eliminate the above-mentioned drawbacks of the conventional technology.A polarizer, a modulator, and an analyzer, which also have parallel flat end surfaces, are bonded to a solid-state laser whose ends are parallel flat, and the entire The object of the present invention is to provide a device that integrates the above and emits modulated coherent laser light.

This invention will be explained below. Fig. 2 shows an embodiment of the present invention, in which 1' is a laser active medium whose both ends are parallel planes, 9 is a parallel plate-shaped east-focusing optical lens, and one end face has a laser beam wavelength. It is coated with a reflective film 4' that has a reflectance of 100% for the light.

On the other hand, one end face of the laser medium 1' is coated with a reflective film 5' having a reflectance of 90 to 99.7% for light at the laser oscillation wavelength. 6' is a flat polarizer, 7' is a modulator made of a crystal having an electro-optic effect, and 8' is a flat analyzer. Reference numerals 10 and 11 are plastics supporting the condensing optical lens 9 and the modulator 7', respectively, and the rest is the same as in FIG. Each of the above parts is bonded with an adhesive having a refractive index value as close as possible to the refractive index of each other. Next, the operation will be explained.

The light from the light emitting diode 2 passes through the condensing optical lens 9 and is condensed onto the laser active soot material 1' by the condensing lens 3.
Excite this. The reflective films 4' and 5' constitute a laser resonator, and the laser beam passes through the reflective film 5' due to the partial transparency of the reflective film 5' and enters the polarizing plate 6'. The light exiting the polarizing plate 6' is polarized and enters the modulator 7'. The direction of polarization at this time is set to form an angle of 45° with respect to both the crystal orientation in which the electrodes of the modulator 7' are attached and the crystal orientation perpendicular thereto. The voltage applied to the modulator 7' causes the polarization of the light leaving the modulator 7' to be different from the original polarization vector. Therefore, if the direction of the polarization vector of the analyzer 8' is set perpendicular to the polarization vector of the polarizing plate 6',
The light will undergo vibrational modulation due to the voltage. As explained above, according to the present invention, the components of each part are all parallel plate shapes, and by bonding each part with an adhesive having an appropriate refractive index, the laser oscillation part and the modulation part are integrated. The entire structure is a 4-inch type, and delicate optical adjustment between each component can be eliminated.

Furthermore, since the laser resonator is a so-called hemispherical resonator, coherent light with a smaller beam divergence angle can be obtained by using the method of the present invention in which light is extracted from the crystal side. This means that extremely high coupling efficiency can be expected in coupling to optical fibers.

[Brief explanation of the drawing]

FIG. 1 is a schematic structural diagram showing an example of a conventional solid-state laser device, and FIG. 2 is a schematic structural diagram showing an embodiment of the present invention. In the figure, 1' is Caesar active soot, 2 is a light emitting diode,
3 is a condenser lens, 4' and 5' are reflective films, 6' is a polarizing plate,
7' is a modulator, 8' is a detection plate, and 9 is a condensing optical lens with parallel end surfaces. Note that the same reference numerals in the figures indicate the same or corresponding parts. Figure 1, Figure 2

Claims (1)

[Scope of Claims] 1. The other end face of a laser active medium whose one end face is coated with a reflective film is adhered to the other end face of a parallel plate-shaped focusing optical lens whose one end face is coated with a reflective film, A solid-state laser device characterized in that a polarizing plate, a modulator made of a crystal having an electro-optic effect, and an analyzer plate are successively adhered to each other and integrated with the reflective film of the laser active medium. 2. The reflectance at the laser oscillation wavelength of the reflective film coated on one end surface of the condensing optical lens is 100%.
2. The solid-state laser device according to claim 1, wherein the laser beam is extracted from the modulator side by setting the reflectance of a reflective film coated on one end face of the laser active medium to 90 to 99.7%.