JP2000352632A - Awg module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize (make thin) a module the whole of which is enclosed with a package as much as possible by using an electronic cooling element for adjusting the temperature of an AWG(array waveguide diffraction grating) chip. SOLUTION: A package 40 is formed by a vacuum heat insulating system in which a vacuum chamber 42 enclosed by a double wall is utilized. An electronic cooling/heating element 24 is housed in the inside of the double wall of the vacuum chamber 42. The surface 240 in use and the opposite surface 242 of the cooling element 24 are respectively brought into close contact with the inner wall 420 and the outer wall 422 of the vacuum tank. Thus, heat generating from the opposite surface 242 of the cooling element 24 hardly enters in the inside of a closed space 45. Therefore, the temperature within the package 40 is precisely controlled. Since the cooling element 24 serves as a supporter between the inner wall 420 and the outer wall 422 of the vacuum chamber 42, the strength of a module is increased. The module is further thinned by embedding a chip temperature detecting sensor into the inside of a chip.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a module of an arrayed waveguide diffraction grating (hereinafter, AWG),
It relates to a part related to temperature control of the AWG chip.

[0002]

2. Description of the Related Art An example will be described with reference to FIG. FIG. 3A is a schematic plan view, and FIG. 3B is a cross-sectional view taken along line BB of FIG. Reference numeral 10 denotes an AWG chip, 11 denotes a substrate, 12 denotes an input / output waveguide, 14 denotes a slab waveguide, and 16 denotes an arrayed waveguide group having different lengths. With these structures, this optical element functions as an optical multiplexer / demultiplexer.
Are well known and will be omitted. The input / output waveguide 12 and the external optical fiber 20 are connected via the optical fiber array 18. The AWG chip 10 and the optical fiber array 18 are made of a pedestal 22 made of metal such as aluminum or glass or ceramic.
(FIG. 6B).

An electronic cooling / heating element 24 utilizing the Peltier effect is mounted directly below the AWG chip 10 via a pedestal 22. The AWG chip 10 is a planar waveguide made of a quartz substrate, and has a problem that the central wavelength of each channel of the arrayed waveguide group 16 in the optical multiplexing / demultiplexing changes due to the large temperature dependence of the refractive index of the quartz optical waveguide. Have. Therefore, a sensor (not shown) for measuring the temperature of the AWG chip 10 and the electronic cooling / heating element 2
The center wavelength is controlled while maintaining a constant temperature by an automatic control mechanism including the control unit 4. Reference numeral 26 denotes a pedestal, and reference numeral 30 denotes a package that wraps the entire above and insulates and seals. Reference numeral 25 denotes a metal electric wire connected to the electronic cooling / heating element 24.

[0004]

The electronic cooling and heating element 2
4 is used for cooling, that is, if the inside is a cooling side and the outside is a heating side, the opposite surface 242 (the used surface 24)
The heat of the surface (the surface paired with 0) is confined in the package 30 and hinders the cooling function. Conversely, when the electronic cooling / heating element 24 is used for heating, the heating function is hindered for the same reason. The electronic cooling / heating element 24 itself usually has a thickness of about 3 to 4 mm, which hinders the miniaturization (thinning) of the package 30. Depending on the usage conditions of the module, the temperature of the AWG chip 10 is not always uniform at every position. Particularly, it is the portion of the arrayed waveguide group 16 that wants to keep the temperature constant. Therefore, it is necessary to consider a mounting position of a temperature sensor capable of detecting the temperature of the arrayed waveguide group 16 most accurately.

[0005]

Means for Solving the Problems The first aspect of the present invention is shown in FIG.
As an example, a vacuum insulation type using a heat insulation tank, for example, a vacuum tank 42 surrounded by a double wall (particularly indicated by a thick solid line) is used as the package 40. The electronic cooling / heating element 24 is housed in the double wall 42 and its use surface 240 is closely attached to the inner wall 420 of the vacuum chamber 42, and the opposite surface 242 is closely adhered to the vacuum chamber outer wall 422.

As described above, the closed space 4 in the package
5 becomes highly thermally insulated from the outside. Further, in the above-described manner, heat (or cool air) generated from the opposite surface 242 of the electronic cooling and heating element 24 is transmitted to the closed space 45.
Most of them do not get inside. Further, the electronic cooling and heating element 24 becomes a support between the inner wall 420 and the outer wall 422 of the heat insulating tank, for example, the vacuum tank 42, and the strength is increased.

According to a second aspect of the present invention, as shown in FIG. 2, the package 40 is of a vacuum insulation type using a heat insulation tank, for example, a vacuum tank 42 surrounded by double walls. This is the same as the case of claim 1), a hole 424 is provided in a part of a heat insulating tank, for example, a vacuum tank 42, and the electronic cooling / heating element 24 is fitted therein.
Is the feature.

In this case, it is necessary that there is no gap between the hole 424 and the thermoelectric cooling element 24 to be fitted. If there is a gap, the closed space 45 cannot be held. As a method of forming the hole, for example, a through portion having a size large enough to allow the electronic cooling and heating element 24 to be inserted is formed in the wall of the vacuum chamber 42. Then, the electronic cooling and heating element becomes a part of the wall of the vacuum chamber.

The use surface 240 of the electronic cooling and heating element 24 is
The AWG chip 10 is made to face the AWG chip 10 via a pedestal 22 made of a metal having good thermal conductivity, for example, aluminum.

A heat sink 4 is provided on the lower surface of the package 40.
6 is desirable. This heat sink 46
Thus, heat or cool air from the electronic cooling and heating element 24 is
Released. Also, the opposite surface 24 of the electronic cooling and heating element 24
2 is thermally connected to the outer wall 422 of the vacuum chamber 42.

When the heat sink 46 is not used, it is better to take appropriate means for thermally connecting the opposite surface 242 of the electronic cooling / heating element 24 and the outer wall 422 of the package 40.

According to a third aspect of the present invention, as shown in FIG. 3 (a), the temperature sensor 50 is provided at a position substantially at the center of the arrayed waveguide group 16 on the upper surface of the AWG chip 10, for example, at a distance a from both ends. And at a position where the distance b from the center is substantially equal. That is, the positions are point-symmetric.

The appearance of the arrayed waveguide group is generally fan-shaped. However, as shown in FIG. 3B, when the arrayed waveguide group 16 is substantially semicircular, the temperature sensor 50 is arranged near the center of the curve. Will do.

By arranging the temperature sensor 50 at the above position, the average temperature of the arrayed waveguide group 16 can be accurately detected as a whole.

In this case, the structure of the package and the mounting position of the electronic cooling / heating element 24 do not matter.

According to a fourth aspect of the present invention, as shown in FIGS. 4 and 5, grooves 110 and 112 are formed in the AWG chip 10, and a temperature sensor 50 is disposed in the position of the third aspect. To do.

With the above configuration, since the temperature sensor 50 does not appear on the surface of the substrate 11, the internal temperature of the quartz substrate can be accurately measured, which contributes to a reduction in the thickness of the entire module.

[0018]

First Embodiment FIG. 1 will be described. The package 40 includes a vacuum tank 42, which is a heat insulating tank, and a lid 44. The external shape of the vacuum chamber 42 is, for example, a rectangular parallelepiped with a part of the left side open in the figure. A heat insulating lid 44 is fitted into the open part, and a closed space 45 is formed inside. Vacuum chamber 4
Reference numeral 2 denotes a hollow double-wall structure similar to a thermos bottle (43 is a substantially vacuum portion) and is made of metal such as stainless steel. An AWG chip 10, an optical fiber array 18,
The pedestal 22 and the like are mounted in a conventional manner. However, the heat insulation tank is not limited to a vacuum tank as long as it has an excellent heat insulation effect.

The electronic cooling and heating element 24 is housed in the double wall of the vacuum chamber 42 below the AWG chip 10. Then, the use surface 240 is brought into close contact with the inner wall 420 of the vacuum chamber 42, and the AWG chip 1 is inserted through the inner wall 420 and the pedestal 22.
0 is cooled or heated. In addition, the opposite surface 242 is
2 and discharge heat or cold air to the outside through the outer wall 422. Further, a heat sink 46 is attached as needed.

The temperature sensor 50 is, for example, a thermistor, and is attached to the position shown in FIG. 3 on the upper surface of the substrate 11 of the AWG chip 10 by using, for example, a heat conductive adhesive. This position is inside the arrayed waveguide group 16,
It is preferable that the point is substantially point-symmetric with respect to the arrayed waveguide group and is located at the center. In addition, the average temperature of the entire substrate can be measured in the center. Since the lead wire 52 is a metal wire and it is not necessary to consider the curvature of bending, a gap is appropriately found and the lead wire 52 is pulled out from the lid 44.

[0021]

Embodiment 2 Referring to FIG. FIG. 3A is an explanatory view of the package 40 cut from the center and viewed obliquely from below, FIG. 3B is an explanatory view of a transverse side surface of the package 40, and FIG. A hole 424 (a through hole formed in a wall portion) is provided on the lower surface of the vacuum chamber 42 of the package 40. The electronic cooling / heating element 24 is fitted into the hole 424. The space between the electronic cooling / heating element 24 and the hole 424 is made airtight so that the sealed space 45 inside the package 40 is held. The use surface 240 of the electronic cooling / heating element 24 is in contact with the pedestal 22, and cools or heats the AWG chip 10 via the pedestal 22.

The thickness a of the double wall of the vacuum chamber 42 is made equal to the thickness b of the electronic cooling and heating element 24 so that no step is formed between the inner and outer walls of the vacuum chamber 42 and the electronic cooling and heating element 24. It is better to do.

Further, a heat sink 46 is attached, thereby facilitating the release of heat or cool air from the electronic cooling and heating element 24, and the heat sink 46 connects the outer wall 422 of the vacuum chamber 42 to the opposite surface 242 of the electronic cooling and heating element 24. Thermal connection was made.

The temperature sensor 50 is mounted at the same position as in the first embodiment.

[0025]

Third Embodiment The mounting position of the temperature sensor 50 corresponds to claim 4 described above. As shown in FIG. 4A, a bottomed groove 1 is formed on the upper surface of the substrate 11 of the AWG chip 10.
Form 10. The groove 110 starts from, for example, one side of the substrate 11 and reaches the position shown in FIG. The temperature sensor 50 with the lead wire 52 is housed in the tip of the groove 110 (FIG. 4B). Then, the gap is filled with a filler 54 (for example, a heat conductive paste) (FIG. 3C).

[0026]

Fourth Embodiment Similarly, the present invention relates to a mounting position of a temperature sensor 50. As shown in FIG. 5A, a groove 112 without a bottom (from the upper surface to the lower surface) is formed on the substrate 11. Also in this case, the groove 112 starts from, for example, one side of the substrate 11 and reaches the position shown in FIG. Next, as shown in FIG. 2B, only the temperature sensor 50 (for example, a thermistor chip) having no lead wire is housed in the tip of the groove 112.
Adhesive sealing with a filler 54 is performed. Then, the electrodes 56 of the temperature sensor 50 are formed on both surfaces (or one surface) of the substrate 11 by, for example, gold deposition. Lead wire 52 to electrode 56
Is applied by solder or conductive paste.

[0027]

According to the first and second aspects of the present invention, since the electronic cooling and heating element 24 is built in the vacuum portion 43 of the vacuum chamber 42, heat (or cold air) generated from the opposite surface 242 of the electronic cooling and heating element 24 is obtained. ), But hardly enters the closed space 45. Therefore, the temperature inside the package 40 can be precisely controlled. The electronic cooling / heating element 24 becomes a support between the inner wall 420 and the outer wall 422 of the vacuum chamber 42, and the strength is increased. The thickness can be reduced as compared with the conventional package 30. In the case of the third aspect, it is possible to accurately detect the average temperature change of the arrayed waveguide group 16 and the entire substrate. In the case of the fourth aspect of the invention, the thickness of the package can be particularly reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory view of the present invention according to claim 1;

FIGS. 2A and 2B are explanatory views of the present invention according to claim 2, wherein FIG. 2A is a view of the package 40 cut from the center and viewed obliquely from below, FIG. Is a view of the entire transverse side.

FIG. 3 is an explanatory view of the present invention according to claim 3;

FIG. 4 is an explanatory view of the present invention according to claim 4;

FIG. 5 is an explanatory view of another embodiment of the present invention according to claim 4;

6A and 6B are explanatory views of a conventional technique, wherein FIG. 6A is a plan view and FIG.
3A is a cross-sectional view taken along line BB of FIG.

[Explanation of symbols]

 Reference Signs List 10 AWG chip 11 Silicon substrate 110 Groove (with bottom) 112 Groove (without bottom) 12 Input / output waveguide 14 Slab waveguide 16 Arrayed waveguide group 18 Optical fiber array 20 Optical fiber 22 Pedestal 24 Electronic cooling / heating element 240 Working surface 242 Opposite surface 25 Metal wire 26 Pedestal 30 Package 32 Temperature sensor 34 Metal wire 40 Package 42 Vacuum tank 420 Inner wall 422 Outer wall 424 Hole 43 Vacuum part 44 Cover 45 Sealed space 46 Heat sink 50 Temperature sensor 52 Lead wire 54 Filler 56 Electrode

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaki Mikami, Sakura Plant, 1440, Misaki, Sakura City, Chiba Prefecture Fujikura Co., Ltd. (72) Inventor Ken Ken Sasaki 1,440, Misaki, Sakura City, Chiba Prefecture, Fujikura Co., Ltd. (72) Inventor Katsutoshi Komoto 1440 Mutsuzaki, Sakura City, Chiba Prefecture Inside Fujikura Sakura Plant (72) Inventor Ken Takeshi 1440 Mutsuzaki, Sakura City, Chiba Prefecture Inside Fujikura Sakura Plant F-term (reference) 2H047 KA02 KA03 KA12 LA01 MA05 QA07 TA00 2H049 AA59 AA62 AA68 5F036 AA01 BA33 BF01

Claims (4)

[Claims] An AWG module in which an AWG chip is held at a constant temperature by a temperature sensor and an electronic cooling / heating element and a package 40 encloses the AWG chip, the temperature sensor, and the electronic cooling / heating element. As the package 40, a heat insulating type is used, the electronic cooling / heating element 24 is housed in the wall of the heat insulating tank 42, the use surface 240 is set on the inner wall 420 of the heat insulating tank 42, and the opposite surface 242 is set on the opposite surface 242. AW characterized in that it is in close contact with the outer wall 422 of the heat insulating tank.
G module. 2. An AWG module in which the AWG chip 10 is maintained at a constant temperature by a temperature sensor and an electronic cooling / heating element 24, and wherein the AWG chip 10, the temperature sensor, and the electronic cooling / heating element 24 are wrapped in a package 40. And the heat insulating tank 4 as the package 40.
An AWG module characterized by using a heat-insulating and heat-insulating method using the heat-insulating tank 2, providing a hole 424 in a part of the heat-insulating tank 42, and fitting the electronic cooling / heating element 24 into the hole 424. 3. An AWG module in which the AWG chip 10 is maintained at a constant temperature by a temperature sensor and an electronic cooling / heating element 24, and wherein the AWG chip 10, the temperature sensor, and the electronic cooling / heating element 24 are wrapped in a package 40. An AWG module, wherein the temperature sensor is arranged at a position substantially at the center of the arrayed waveguide group 16 on the upper surface of the AWG chip 10. 4. The AWG module according to claim 3, wherein the temperature sensor is arranged not in the upper surface of the AWG chip 10, but in a groove formed in the substrate of the AWG chip 10.