JPS60150025A - Optical superposition system for laser beam - Google Patents

Abstract

PURPOSE:To reduce loss of superposition and to improve its precision by using an optical element which has plural total reflecting surfaces so coated as to obtain total reflection to laser beams when plural laser beams are superposed. CONSTITUTION:Parallel laser beams (a) and (a') emitted from individual laser oscillators are reflected totally by the V-shaped optical element 11 which has reflecting surfaces 11a and 11a' so coated as to obtain total reflection to the respective incident laser beams, thereby obtaining beams which travel in the same direction and have optical axes in parallel to each other. Those beams are incident to a lens system 2 for convergence. The laser beam projected from the lens system 2 is converged on the core part 31 of an optical fiber transmission line 3 and passed through the optical fiber transmission line 3, so that the incident laser beams (a) and (a') are superposed on the same optical path. Thus, plural laser beams are superposed on the same optical path with low loss and high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-beam superposition type optical system that aims to superimpose a plurality of laser beams on the same optical path.

In recent years, laser beams have been used in measurement equipment and medical equipment.

Laser oscillators, CO2 lasers, A
r laser, He-Ne laser, YAGL/- laser oscillator, etc. Furthermore, the oscillation mode of the laser includes continuous oscillation, pulse oscillation, Q-switch oscillation, etc., and various choices can be made depending on the purpose of use.

If the diversified laser beams mentioned above can be superimposed on the same optical path, it will be possible to open up fields of application that have not been possible until now.

Conventionally, a semi-transparent mirror has been used to superimpose multiple laser beams on the same optical path, but this method has a loss of 50%.
Because of its extremely large size, it was only used in a limited area.

An object of the present invention is to provide an optical system that can superimpose a plurality of laser beams on the same optical path with low loss and high precision.

The laser beam superimposition optical system of the present invention includes an optical element having a plurality of reflective surfaces coated with a total reflection coating for an incident laser beam, and a plurality of laser beams reflected by the reflective surfaces. The laser beam is composed of a lens system and an optical fiber transmission line for guiding the laser beam focused by the lens system.

According to the present invention, the superposition of multiple laser beams, which was conventionally achieved using a semi-transparent mirror, can be achieved by using a plurality of total reflection surfaces coated with total reflection coating for laser beams, without using a semi-transparent mirror with a large loss. By using optical elements, it is possible to keep loss to an extremely low level, and by guiding multiple laser beams reflected by multiple total reflection surfaces into an optical fiber using a focusing lens system, it is possible to easily align them on the same optical path. It becomes possible to superimpose the beams on each other.

Furthermore, the effect of using this optical fiber transmission line is
Institute of Electronics and Communication Engineers, published July 19, 1979, 0QE79-
58, pp. 43-47, Yanase.

As stated in Mr. Shirane's paper "High-power laser beam transmission using optical fiber", especially in the section "[3] Application to processing" in the left column of page 46, the energy of the laser beam emitted from the fiber This shows that the intensity distribution has a shape close to the refractive index distribution of the fiber used because the mode conversion of the laser beam takes place within the fiber.

This means that by using the laser beam superimposition optical system according to the present invention, the intensity distribution of the laser beam emitted from the optical system is always constant regardless of the energy intensity distribution of the incident laser beam. This shows that it is possible to provide a laser beam with

C1 The laser beam stacking optical system according to the present invention makes it possible to easily obtain a high-energy laser beam by combining a number of laser beams with low energy, and it is also possible to easily obtain a high-energy laser beam by combining a number of laser beams with low energy. Due to its high alignment accuracy, by superimposing laser beams with different oscillation wavelengths or different oscillation forms, new means can be developed in fields such as microfabrication, medical care, and chemical experiments that require various conditions. It becomes possible to provide

Next, embodiments of the invention will be described with reference to the drawings.

Figure 1 is a cross-sectional view showing an embodiment of the present invention, in which laser beams (parallel beams) are emitted from separate laser oscillators.
a, a' are reflective surfaces 11 a t 1 each coated with a total internal reflection coating for each incident laser beam.
The laser beams are totally reflected by the V-shaped optical element 1 having an angle of 1 a' to form beams having the same direction and optical axes parallel to each other, and enter a lens system 2 for focusing these laser beams. The beam emitted from the lens system 2 is focused on the core portion 31 of the optical fiber transmission line 3, and passes through the optical fiber transmission line 3 to become an incident laser beam a,
a' all overlap on the same optical path. In the figure, 32 is a cladding layer of the optical fiber.

FIG. 2 is a block diagram showing an example of the use of the embodiment of the present invention.
Laser beams emitted from two laser oscillators, each with a different oscillation wavelength, are guided to the irradiation site at a separate location via an optical fiber transmission line, and the irradiated object is irradiated with two different wavelengths. Laser beams, each singly,
Alternatively, a system for superimposing irradiation is shown.

Laser oscillators with different oscillation wavelengths 100°100
The laser beams a and a' emitted from the optical fibers 200 and 200' are coupled to the optical fiber transmission lines 3 and 3', respectively, by the coupling optical system sections 200 and 200'. The light transmitted through this optical fiber transmission line is converted into a parallel beam by a parallel beam output optical system 4.4', and a laser beam superimposing optical system section 5 located at a distance from the laser oscillator 100, 100' incident on . The laser beam superimposing optical system section 5 consists of the optical system shown in FIG. 1, and superimposes the laser beams a and a' emitted from the parallel beam emitting optical systems 4 and 4' on the same optical path, and transmits them through an optical fiber. The superimposed laser beam b emitted from the path 3 is emitted to the irradiation lens system 6. The irradiation lens 6 focuses the laser beam b onto the object 7 to be irradiated.

Therefore, by using various oscillation forms for the laser oscillators 100 and 100', various superimposed beams can be obtained and the range of use of the laser beam can be expanded.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the invention, and FIG. 2 is a block diagram showing an example of use of the invention. In the figure, a, a""...' laser beam, 11 a
+ 11 a'...Reflecting surface subjected to total reflection for the incident laser beam, 1...
Optical element, 2... Lens system, 3... Optical fiber transmission line, 31... Optical fiber core, 32... Optical fiber cladding layer s 10
01100'--v-the oscillator, 200-0...
Coupling optical system, 3... Optical fiber transmission line, 4.
... Parallel beam output optical system, 5 ... Laser beam alignment optical system, 6 ... Irradiation lens system, 7 ... Irradiated object, b. ...They are superimposed laser beams.

Claims (1)

[Claims] an optical element having a plurality of reflective surfaces coated with a total reflection coating for an incident laser beam; a lens system that focuses the plurality of laser beams reflected by the reflective surfaces;
A laser beam superposition optical system including an optical fiber transmission line for guiding the laser beam focused by the lens system.