JPH118486A - Liquid-cooled device for optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the method for manufacturing a device and reduce the cost therefor by arranging optical modules on a concentric circle and forming tubes for passing liquid refrigerant into axial symmetry, so that the optical modules are brought into almost the same temperature and the oscillating characteristic of a laser is stabilized, and utilizing a screw groove to form a spiral path. SOLUTION: A liquid-cooled device is for mounting a plurality of optical modules 6 thereon and cooling the optical modules 6. The liquid-cooled device comprises an outer cylinder 1 on which the optical modules 6 are mounted, and an inner cylinder 2 which is fit into the outer cylinder 1 in such a manner such that the inner cylinder 2 is brought into contact with the inside of the outer cylinder 1, and has a spiral screw groove 3 on the surface of its circumference. The outer cylinder 1 has an inlet 7 into which liquid is let flow and an outlet 8 from which the liquid is let flow, and the plurality of the optical modules 6 are mounted so that the optical modules 6 are positioned on one circle on the circumference of the outer cylinder 1 at equal intervals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid cooling device for cooling an optical module such as a laser diode module.

[0002]

2. Description of the Related Art Recent advanced optical semiconductor technologies have both the characteristics of coping with high frequencies and increasing the output depending on the application. In optical fiber communication, which is the backbone of advanced information networks, in order to transmit voice information, still images, moving images, etc. handled in multimedia in a large amount in a short time, optical semiconductors for oscillation and reception corresponding to high frequencies are required. It has been demanded. On the other hand, regarding the increase in output of optical semiconductors, in addition to optical fiber communication, there are also uses for machining and the like, and when a laser diode element or the like is used for such an application, the output of a plurality of laser diode elements And a method of obtaining a large output by exciting another laser.

[0003] By the way, when the output of the optical semiconductor device is increased as described above, a mechanism for cooling the device becomes necessary. Taking a laser diode or the like as an example, it is usually necessary to keep the temperature constant near room temperature in order to stabilize the output characteristics, and cooling and stabilizing are performed using an electronic cooling element such as a Peltier element. However, in the case of an apparatus having a plurality of high-output optical semiconductors mounted thereon as described above, it is difficult to achieve a predetermined cooling temperature only with the electronic cooling element. Moreover, in some cases, the total output of the plurality of optical modules may reach several hundred watts,
At this time, the cooling capacity may be insufficient even with normal forced air cooling.

[0004] In the field of semiconductor devices, water-cooling has been conventionally used when devices having particularly large heat values are densely mounted. As an example of using water cooling for cooling a supercomputer, see NEC Technical Report Vol. 39 No.
1P. 36 (1986). As described in this content, the water cooling mechanism is to curve a pipe in a zigzag shape, install the pipe on or inside a substrate, and cool a semiconductor device mounted on the surface of the substrate. When this liquid cooling mechanism is applied to the above-described high-power optical module, a plurality of optical modules are mounted on a substrate made of a material such as aluminum or copper having high heat dissipation efficiency, and a coolant is provided inside or on the back of the substrate. It is easy to imagine a method of installing a pipe for flowing a liquid, and efficiently releasing a large amount of heat generated in the optical module to the liquid.

FIG. 3 is a side view of an example of a conventional liquid cooling device for an optical module to which a water cooling mechanism of a semiconductor device is applied. In the figure, reference numeral 1 denotes a substrate on which a laser diode module (hereinafter referred to as an LD), which is a kind of an optical module, is provided.
3) are mounted. A tube 2 for flowing a liquid is adhered to the lower surface of the substrate 1.

FIG. 4 is a top view of the conventional liquid cooling device for an optical module of FIG. In the figure, 1 is a substrate, 2 is a tube, and 3 is an LD module. The pipe 2 for flowing the liquid as the refrigerant is curved in a zigzag shape to increase the cooling efficiency. At present, the present inventors have prototyped a liquid cooling device for an optical module having such a structure.

[0007]

However, in the liquid cooling device for an optical module having the above-described structure, the arrangement and shape of the tube through which the liquid flows are not symmetrical and are mounted near the liquid inlet. The laser diode mounted near the liquid outlet has a higher temperature than the laser diode, and has a disadvantage that the laser characteristics of the respective optical modules are not stable. Also,
When a large number of optical modules are mounted, there is also a problem that the device becomes large.

An object of the present invention is to make the temperature of each optical module during operation substantially the same for a plurality of mounted optical modules, to enable stable laser output, and to occupy a small volume in the entire cooling device. It is to provide a small cooling device.

[0009]

To achieve the above object, a liquid cooling apparatus for an optical module according to the present invention comprises:
An outer cylinder on which an optical module is mounted on the outer surface, and an inner cylinder provided with a helical thread groove on the outer surface so as to be in contact with the inside of the cylinder, the outer cylinder has an inlet through which liquid flows, and a liquid through which the liquid flows. The outer and inner cylinders are covered with lids on the upper and lower surfaces, and the positions of the plurality of optical modules are substantially the same on the outer circumference at approximately the same distance from one end of the cylinder. It is characterized by a structure mounted at intervals.

The outer surface of the outer cylinder can be formed in a regular polygonal shape for mounting the optical module, and the outer cylinder and the inner cylinder can each be cylindrical.

In the liquid cooling device for an optical module according to the present invention, the position arrangement of each of the plurality of arranged optical modules and the shape of the tube through which the liquid as the refrigerant flows are concentric, so that the optical modules operate. The temperature of the laser diode at this time is substantially the same for each optical module. Furthermore, when the number of optical modules to be mounted becomes large, it is possible to reduce the size of the device by disposing it on a cylinder rather than on a flat plate. Also, regarding the formation of the flow path of the liquid as the refrigerant, the structure of the present invention in which the screw-shaped tube is combined is superior to the formation of the pipe in terms of the simplicity of the manufacturing process.

[0012]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 are a sectional view and a top view, respectively, showing a liquid cooling apparatus according to the present invention. In the figure,
Reference numeral 1 denotes an outer cylinder having an inner surface in the shape of a cylinder and an outer surface in the shape of a regular polygonal prism, and is made of a material having high thermal conductivity such as copper or aluminum. Reference numeral 2 denotes an inner cylinder, the outer circumference of which is approximately the same size as the inner circumference of the outer cylinder, and in which a spiral groove is formed. Actually, since the inner cylinder 2 is inserted into the outer cylinder 1, the flow path 3 through which the liquid as the refrigerant flows is formed. Reference numeral 4 denotes an upper lid provided on the upper surfaces of the outer cylinder 1 and the inner cylinder 2, and similarly, 5 denotes a lower lid. Reference numeral 6 denotes a plurality of LD modules installed on the outer periphery of the outer cylinder. In the present embodiment, four LD modules are mounted.
Is square. The positional relationship between the LD modules is such that a plurality of LD modules are arranged at regular intervals on the same circumference of the outer cylinder 1. Above and below the outer cylinder 1, holes for liquid inlet 7 and outlet 8 are provided, respectively.
It is connected with. The liquid as a refrigerant has a structure that enters from the inlet 7 and exits from the outlet 8, and cools the LD module 6 by such a structure. In the liquid cooling device of the present invention, the LD modules are arranged concentrically, and the pipe through which the liquid refrigerant flows is nearly axially symmetric. Characteristics become stable. Further, the method of forming the spiral flow path can be formed only by fitting the outer cylinder 1 and the inner cylinder 2, and the manufacturing method is low in cost. In the present embodiment, the outer shape of the outer cylinder is square, but may be formed in a regular polygonal shape or a cylindrical shape.

In the liquid cooling device having the structure in which the LD module is mounted on the cylinder and the liquid cooling device having the structure in which the LD module is mounted on the flat plate of the present invention, the temperature when the LD is operated is measured. The variation in each module was measured and compared. In a liquid cooling device having a structure in which an LD module is mounted on a flat plate, the temperature difference between the LDs is 8 ° C.
Met. On the other hand, in the liquid cooling device of the present invention in which the LD module is mounted on the cylinder, the temperature difference between the LDs was 1 ° C. As described above, the liquid cooling device having the structure in which the LD module is mounted on the cylinder according to the present invention is more effective than the liquid cooling device having the structure in which the LD module is mounted on a flat plate between the LDs in which a plurality of LDs are mounted. It was found that the temperature variation was small.

In the above embodiment, the L
Although the case where the number of D modules is four has been described, the number of mounted modules is arbitrary and the same effect can be obtained.

[0016]

As described above, according to the present invention,
The temperature of each of the plurality of optical modules becomes substantially the same, and the effect of improving the characteristics of the optical semiconductor is obtained.
Furthermore, the volume occupied by the cooling device is reduced, and the size of the device can be reduced. In addition, the method of forming the cooling device is simple and inexpensive.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a top view of the embodiment shown in FIG.

FIG. 3 is a side view of a conventional liquid cooling device for an optical module.

FIG. 4 is a top view of the conventional example shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer cylinder 2 Inner cylinder 3 Flow path 4 Upper lid 5 Lower lid 6 LD module 7 Inlet 8 Outlet

Claims (3)

[Claims] 1. A liquid cooling device for mounting and cooling a plurality of optical modules, comprising: an outer cylinder on which an optical module is mounted on an outer surface; It has an inner cylinder provided with a helical thread groove on the outer surface, the outer cylinder has an inlet through which liquid flows in, and an outlet through which liquid flows out, and each end face of these outer cylinder and inner cylinder is A liquid cooling device for an optical module, wherein the optical module is closed by a lid, and is mounted at substantially equal intervals on the outer circumference at substantially the same distance from one end surface of the outer cylinder. 2. The outer surface of the outer cylinder is formed in a regular polygonal column shape,
2. The liquid cooling device for an optical module according to claim 1, wherein an optical module is mounted on each of the pillar surfaces. 3. The liquid cooling device for an optical module according to claim 1, wherein the outer cylinder and the inner cylinder each have a cylindrical shape.