JPS6242477A - Laser oscillation device - Google Patents

Abstract

PURPOSE:To enable transmission without requiring any additional optical system for the optical fiber by an arrangement wherein the optical fiber is made to also act as a resonator mirror and integrated with the optical guide path. CONSTITUTION:The electrodes 31, 32 oppositely attached on the outer surface of a thin tube 30 are connected to a RF power supply 33. In one end of the thin tube 30 a highly reflective mirror 36 is airtightly inserted orthogonally with the axis of an optical guide path 35. In the other end, an optical fiber 37, the core diameter of which is substantially same as the diameter of the reflecting surface of the highly reflective mirror 36, is inserted so that the whole surface of the core blocks up the optical guide path 35, maintaining the optical guide path 35 and the outside air in airtightness. The core end opposite to the highly reflective mirror 36 has been applied with a coating treatment so as to have a predetermined reflectance for also acting as the output mirror. In this arrangement, an optical resonator is constructed with the highly reflective mirror 36 and the end face of the optical fiber 37, and the reflected light 40 is transmitted using the optical guide path 35 as a wave guiding path. Therefore, an optical system for incidence becomes unnecessary.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a waveguide type laser oscillation device.

[Technical background of the invention and its problems]

Conventionally, this type of laser oscillation device has a set of internal mirrors.
As shown in FIG. 4, it has a double-structured tube body (3) with a thin tube part (1) in the center and a cooling water flow path (2) around this thin tube part (1), An anode (6) and a cathode (7) connected to a DC power source (5) via a stabilizing resistor (4) are arranged at both ends of the thin tube section (1), and are arranged coaxially with the thin tube section (3). A structure in which both ends of the tube body (3) are closed with a resonator mirror consisting of an output mirror (8) and a high reflection mirror (9), and an electrode C11 on the outer surface of the thin tube section 4 as shown in FIG. ), (13) are mounted facing each other, and a power source 0 is connected to these electrodes.

Note that a cooling pipe t14) for cooling the thin tube portion α1 is brought into contact with one electrode @.

In addition, as shown in Fig. 6, as a set of external mirrors, both ends of the tube body are made with bricoaster windows μe, and the tube body (l!19
There is a structure in which an output mirror (8) and a high reflection a (9) are arranged outside the mirror. Note that in this structure, the anode (US
, the cathode 0 is provided within the tube body 41!9 at a position off the laser optical axis.

In any of the above conventional methods, the resonator mirror is installed at a distance from both ends of the thin tube, so
Fine adjustment of the reflection angle of the resonator mirror is required, and the loss in this part is also insignificant.

In addition, when transmitting the laser light (20) output from these devices through an optical fiber, an optical system such as a condenser lens is required to input the light into the optical fiber, and a mechanism for adjusting the optical system is also required. It's coming.

[Purpose of the invention]

The present invention provides a laser oscillation device that can efficiently oscillate laser output and transmit it through an optical fiber without requiring any other optical system.

[Existing necessity of the invention]

To achieve the above object, at least one of the resonator mirrors is constituted by an optical fiber having an end face formed to have a predetermined reflectance, and the end face is installed at a position that closes a thin tube portion that is a part of a gas laser tube. This is how it was done.

[Embodiments of the invention]

The following will explain based on examples.

FIG. 1 shows a first embodiment of the present invention having an internal mirror-type structure, in which (30) is a thin tube, and electrodes (31) and (32) are mounted facing each other on the outer surface of the tube. There is. These electrodes are connected to an RFi source (33). Further, a cooling pipe (34) is brought into contact with one of the electrodes (32), and serves as a trap to cool the thin tube (30) through the tffl (32). At one end of the thin tube (30), a high reflection mirror (36) having a reflective surface slightly larger than the diameter of the light guide path (35) of the thin tube (30) forms a step with the light guide path (35),
It is inserted perpendicularly to the axis of the light guide (35) in an airtight manner.

In addition, an optical fiber (37) is inserted into the other end, and the core diameter of the transmission path is approximately the same as the reflective surface of high reflection = +2 < 36), which airtightly connects the light guide path (35) and the outside air. It is held in In addition, the inserted optical fiber (37
) forms a step with the light guide path (35), similar to the high reflection collar (36), so that the entire surface of the core closes the light guide path (35). The end face of the optical fiber (37) facing the high reflection m (36), that is, the core end face, is coated to have a predetermined reflectance so as to serve as an output mirror. However, in the case of high gain, the coating treatment described above is not necessary simply by making the core end face optically flat.

In the above configuration, an optical resonator is configured by the high reflection mirror (36) and the end face of the optical fiber (37) facing it, and the reflected light (40) is transmitted using the light guide (35) as a waveguide. Therefore, in this transmission, the Fapley-Perot optical oscillator is the same as the highly reflective ffl (36) and the optical fiber (3
Even if the end faces of 7) do not face each other in parallel, a sufficient resonance effect is achieved, so there is no need to make adjustments to make these both sides accurately face each other in parallel. In addition, a portion of the light that hits the end face of the optical fiber (37) will be directly transmitted into the optical fiber (37), making it possible to create a structure that eliminates the need for an optical system for inputting light as in the past. .

FIG. 2 also shows a second embodiment of the present invention, and parts common to those in FIG. 1 will be described with the same reference numerals. That is, the outer surface of the thin tube (30) is airtightly surrounded by the cooling tube (40), and the anode (41) and cathode (42), which have approximately the same diameter and have stepped through holes at both ends, are surrounded by the thin tube (40). 30
) is coaxial with the axis of the discharge path (35) and hermetically fixed. A DC core source (43) and a stabilizing resistor (44) are connected to the anode (41) and cathode (42). A high reflection mirror (36) is hermetically fixed to the cathode (42) side. On the other hand, an optical fiber (37) is hermetically inserted into the anode (41) side. The end face of the inserted optical fiber (37) is formed into a reflective surface with a predetermined reflectance. In addition, optical fiber (37)
The relationship between the end face of the light guide path (35) and the high-reflection mirror (36) is the same as in the first embodiment. In this configuration as well, the optical system for inputting the light into the optical fiber is used as in the prior art. No longer needed.

By the way, when considering practical use, it is preferable that the fiber diameter is smaller because it is easier to operate. However, considering the practical dimension, in the case of CO, laser, the number of outputs is usually 1.
In the case of a laser tube of approximately 0 W, the dimensions of the light guide path in both FIGS. 1 and 2 are circular, square, or rectangular in cross section, and the diameter or side is approximately several square inches. Furthermore, although there is no advantage and lack of practicality at this stage, for He-Ne lasers and argon lasers, this dimension is usually around 0.5+m, and in the configurations shown in Figures 1 and 2, the fiber diameter is thicker, making it easier to operate. becomes worse.

Figure 3 shows a solution to this problem. In Figure 3 (a), the optical fiber (
In the figure (in the figure), a thin tube (45) with a tapered inner diameter at the end of the optical fiber connection is used; in the figure (C), a plurality of bundled optical fibers (46) with a rectangular cross section are used. ). Of course, some laser light loss occurs in this part, but the advantages are great compared to the conventional method.

When a laser excitation discharge that generates high-energy charged particles is turned on, if the plasma comes into contact with one end of the fiber, the coating on the surface may be damaged. In this case, in the RF (high frequency) discharge shown in FIG. 1, the electrode position is adjusted so that the discharge does not extend to one end face of the fiber. The same applies to the case of DC discharge shown in FIG.

〔Effect of the invention〕

As described above, since the optical fiber doubles as a resonator mirror and is integrated with the light guide path, there is no need for any extra optical parts or adjustments associated with guiding light to the optical fiber. Loss such as reflection and scattering of laser light that had occurred has also been eliminated. Furthermore, since it has an internal mirror configuration, the optical fiber is not exposed to the atmosphere and does not deteriorate due to adhesion of lumps, oxidation, moisture absorption, etc., and it is possible to provide a compact device that is structurally easy to hermetically seal. was completed.

In each of the above embodiments, the optical fiber was airtightly coupled to the thin tube, but instead of the optical 7-eyeper, an optical transmission body (usually called a kaleidoscope), which is made of a prismatic body and has the function of flattening the laser output from a normal distribution, is used. A similar effect can be obtained by using Further, the same applies to a configuration in which the optical 7-eyeper or the like is coupled not to one end but to both ends and the laser light is guided in two directions.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a first embodiment of the present invention, Fig. 2 is a sectional view showing a second embodiment of the invention, and Fig. 3 is an optical fiber coupling in the first and second embodiments. 4 to 6 are sectional views showing conventional examples. (30)...Seven rules (31), (32)
... Electrode (36) ... High reflective mirror (37) ... Optical fiber agent Patent attorney Nori Chika Ga Yudo Take Hana g input 1st prisoner Figure 2 (Hisashi) cb) cl Figure 3

Claims (3)

[Claims] (1) In a laser oscillation device in which a gaseous laser medium is excited by direct current or alternating current in a waveguide-shaped thin tube arranged between resonator mirrors, at least one of the resonator mirrors is formed to have a predetermined reflectance. What is claimed is: 1. A laser oscillation device comprising an optical transmission member having an end face, the end face being installed at a position that closes one end of the thin tube. (2) The laser oscillation device according to claim 1, wherein the optical transmission body is made of an optical fiber. (3) The laser oscillation device according to claim 1, wherein the optical transmission body converts a laser output having a normal distribution into a flat distribution and emits light.