JP2007173648A - Fiber laser device and fiber-laser cooling structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely conduct a cooling by a heat sink even when a fiber is expanded thermally, and to prevent the damage of the fiber. <P>SOLUTION: A fiber laser device has a laser excitation source 11, the fiber F connected to the laser excitation source 11, and a fiber-laser cooler 20 for cooling the fiber F. The fiber-laser cooler 20 has: a main heat sink 30; and a main trench 31 formed along the axial direction of the fiber F on one surface side of the main heat sink 30; a sub heat sink 40 having a sub-trench 41 arranged on one surface side of the main heat sink 30 opposite to the main trench 31 for housing the fiber F in a space formed between the main trench 31 and the sub heat sink 40; and grease G filled in the space formed between the main trench 31 and the sub heat sink 40, and filling the space formed by the fiber F and the main heat sink 30 or the sub heat sink 40. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fiber laser cooling structure for cooling a fiber that is attached to a laser excitation source and performs laser oscillation, and a fiber laser device that emits laser light using the fiber, and in particular, reliably and efficiently cools the fiber. About what can be done.

  A fiber laser device using a fiber as a laser medium is known. This fiber laser device oscillates and amplifies laser light by making excitation light incident on a laser medium such as a rare earth ion added to the core of the fiber from a laser excitation source such as a semiconductor laser.

  In a fiber laser device, a decrease in laser characteristics and a decrease in amplifier characteristics (for example, an increase in oscillation threshold, a decrease in conversion efficiency, etc.) may occur due to an increase in fiber temperature. Further, the covering member for protecting the clad may be deteriorated due to thermal damage.

  FIG. 4 is a side view showing a fiber laser cooling structure used in a fiber laser device for emitting laser light through a fiber, and FIG. 5 is a cross-sectional view taken along the line XX in FIG. FIG. In the figure, F indicates a fiber.

  The fiber laser cooling structure includes a heat sink 100 made of a copper material or the like. A V-shaped groove 101 is formed on the heat sink 100 as shown in FIG. 5, and the fiber F is disposed along the V-shaped groove 101 and fixed to the heat sink 100 by two fixtures 102. As a result, the fiber F is transmitted to the heat sink 100 and cooled.

In addition, various structures for cooling the fiber F are known (see, for example, Patent Documents 1 and 2).
JP-A-5-307117 JP 2001-274489 A

  The above-described fiber cooling structure has the following problems. That is, when the fiber F expands in the longitudinal direction due to heat, the central portion Fa of the portion fixed by the fixing tool 102 is lifted as shown in FIG. For this reason, the cooling is not sufficiently performed, and the fiber F may be thermally damaged.

  Further, in the fiber laser device described in Patent Document 1, since the fiber is not fixed, the fiber moves inside the annular groove, so that it is almost impossible to use in an environment with a lot of vibration. Furthermore, when the fibers overlap each other, there is a problem that the contact area between the main body and the fiber is reduced and the cooling effect of the fiber is reduced.

  Further, in the fiber laser device described in Patent Document 2, since the fiber is wound around the outer peripheral surface of the cylindrical body, there is a problem that the fiber is loosened and the fiber falls off due to the property of trying to straighten the fiber. . Further, when laser oscillation or amplification is performed, the fiber expands from the cylindrical body due to thermal expansion, so that there is a problem that the contact area between the cylindrical body and the fiber decreases and the cooling effect of the fiber decreases.

  Therefore, an object of the present invention is to provide a fiber laser cooling structure and a fiber laser device that can reliably cool a heat sink and prevent damage to the fiber even when the fiber is thermally expanded.

  In order to solve the above problems and achieve the object, the fiber laser cooling structure and the fiber laser apparatus of the present invention are configured as follows.

  A main heat sink, a main groove formed on one surface side of the main heat sink along the axial direction of the fiber to be cooled, and a sub-groove disposed on the one surface side of the main heat sink and facing the main groove A heat-conducting gel filled in a region formed between the main groove and the sub-groove and filling a space formed by the fiber, the main heat sink, and the sub-heat sink. Features.

  A laser pumping source; a fiber connected to the laser pumping source; and a fiber laser cooling unit that cools the fiber. The fiber laser cooling unit includes a main heat sink and the fiber on one surface side of the main heat sink. A main groove formed along the axial direction of the main heat sink and a sub-groove disposed on one surface side of the main heat sink and facing the main groove, and the fiber is placed in a space formed between the main groove and the main groove. A secondary heat sink to be accommodated and a heat conductive gel filling the space are provided.

  According to the present invention, even when the fiber is thermally expanded, it is possible to reliably perform cooling by the heat sink and prevent the fiber from being damaged.

  FIG. 1 is a side view schematically showing a part of a fiber laser device 10 according to an embodiment of the present invention. FIG. 2 shows a fiber laser cooling unit 20 incorporated in the fiber laser device 10 in FIG. FIG. 3 is a cross-sectional view taken along the line Y-Y in FIG. 1 and viewed in the direction of the arrow.

  The fiber laser device 10 includes a laser excitation source 11 such as a semiconductor laser, a fiber F that excites laser light introduced from the laser excitation source 11, and a fiber cooling unit 20 that cools the fiber F.

  The fiber laser cooling unit 20 includes a copper main heat sink 30 and a copper sub heat sink 40 disposed on the upper surface of the main heat sink 30.

  The main heat sink 30 is formed with a semicircular main groove 31 and a V-shaped fixed groove 32 along the longitudinal direction of the fiber F to be cooled. The sub heat sink 40 has a semicircular sub groove 41 facing the main groove 31. The sub heat sink 40 is formed shorter in the longitudinal direction of the fiber F than the main heat sink 30.

  A space having a circular cross section is formed between the main groove 31 and the sub-groove 41, and the space is filled with grease G which is a heat conducting gel, and the fiber F is connected to the main heat sink 30 and the sub heat sink 40. It is arrange | positioned away from. That is, the fiber F is not in direct contact with the main heat sink 30 and the sub heat sink 40.

  One end of the fiber F is fixed to the fixing groove 32 of the main heat sink 30 by a plate-shaped fixing tool 50. Inside the main heat sink 30, a flow passage portion 33 through which cooling water (cooling fluid) flows is formed. The flow passage 33 may be provided on the sub heat sink 40 side.

  In the fiber laser device 10 configured as described above, the fiber F is cooled as follows. That is, when the fiber F generates heat, it is transferred to the main heat sink 30 and the sub heat sink 40 through the grease G. Further, when the fiber F expands in the longitudinal direction due to heat generation, the side fixed by the fixing tool 50 (the right end in the figure) does not move, so that the laser light from the laser excitation source 11 can be introduced without loss. On the other hand, since the other end is freely supported by the grease G between the main groove 31 and the sub-groove 41, the fiber F is not stressed or slackened even if it expands in the longitudinal direction. . Therefore, thermal damage to the fiber F can be prevented.

  As described above, according to the fiber laser device 10 according to the present embodiment, the one end side of the fiber F can be reliably fixed, and even if the fiber F is thermally expanded by laser oscillation, the cooling is reliably performed. The fiber F can be prevented from being damaged.

  Although the main heat sink 30 and the sub heat sink 40 are made of copper, the material is not limited to copper as long as it has a high thermal conductivity. Further, the main groove 31, the fixed groove 32, and the sub-groove 41 are not limited to the shapes described above. Further, there may be a portion where the fiber F directly contacts the main heat sink 30 and the sub heat sink 40. Of course, various modifications can be made without departing from the scope of the present invention.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The side view which simplifies and shows a part of the fiber laser apparatus which concerns on one embodiment of this invention. Sectional drawing which cut | disconnected the fiber laser cooling part incorporated in the fiber laser apparatus by the XX line in FIG. 1, and looked at the arrow direction. Sectional drawing which cut | disconnected the fiber cooling part by the YY line | wire in FIG. 1, and looked at the arrow direction. The side view which shows an example of a fiber laser cooling structure. Sectional drawing of the fixing | fixed part in the same fiber laser cooling structure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Fiber laser apparatus, 20 ... Fiber laser cooling part, 30 ... Main heat sink, 31 ... Main groove, 32 ... Fixed groove, 40 ... Sub heat sink, 41 ... Sub groove, 50 ... Fixing tool, F ... Fiber, G ... Grease (Thermal conduction gel).

Claims (4)

A main heat sink,
A main groove formed along the axial direction of the fiber to be cooled on one surface side of the main heat sink;
A sub heat sink disposed on one side of the main heat sink and having a sub groove facing the main groove;
A heat conductive gel filling a space formed by the fiber, the main heat sink, and the sub heat sink is provided in a region formed between the main groove and the sub groove. Fiber laser cooling structure.   The fiber laser cooling structure according to claim 1, further comprising a fixing member for fixing a part of the fiber to the main heat sink.   The fiber laser cooling structure according to claim 1, wherein a flow passage portion through which a cooling fluid flows is formed in at least one of the main heat sink and the sub heat sink. A laser excitation source;
A fiber connected to this laser excitation source;
A fiber laser cooling section for cooling the fiber,
The fiber laser cooling section includes a main heat sink,
A main groove formed along the axial direction of the fiber on one surface side of the main heat sink;
A sub heat sink disposed on one surface side of the main heat sink, having a sub groove facing the main groove, and housing the fiber in a space formed between the main groove;
A fiber laser device comprising: a heat conducting gel that fills the space.

Images