JP2002156536A - Waveguide type optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waveguide type optical module capable of temperature adjusting optical circuits arranged in plural places at a uniform temperature by reducing temperature distribution within an optical waveguide element. SOLUTION: In the waveguide type optical module having temperature dependence in optical characteristics wherein the optical circuits 1A, 1B and 1C arranged in plural places within the waveguide element are temperature adjusted by using a heater 3, the optical circuits 1A, 1B and 1C which are arranged in plural places are temperature adjusted by plural heaters 3A and 3B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a waveguide type optical module used for optical fiber communication.

[0002]

2. Description of the Related Art A waveguide type optical module having an optical multiplexing / demultiplexing function using a wavelength multiplex transmission system proposed in recent years includes:
Some use a waveguide element whose optical characteristics depend on the ambient temperature around the module. In order to maintain the optical characteristics of this type of waveguide optical module, it is necessary to control the temperature of the waveguide element.

FIGS. 5 and 6 show a conventional waveguide type optical module. An optical fiber 2 is connected to the waveguide element 1. In this waveguide element 1, there are a plurality of optical circuits 1A, 1B, and 1C that require temperature adjustment.

The waveguide element 1 includes a first package 9
The heater 3 is attached to the back surface of the package 9, and the temperature sensor 4 is attached to the surface of the waveguide element 1. First package 9
Is fixed to a second package 7 via a pedestal 6, and a space between the second package and the first package is filled with a heat insulating material 8.

[0005]

In the conventional structure, the first
The heater 3 attached to the center of the back surface of the package 9 heats and adjusts the temperature of the waveguide element 1 attached to the surface of the first package 9. Since heat is radiated through the heat insulating material 8, a temperature distribution in which the center portion is raised occurs in the waveguide element 1 as shown in FIG. There is a problem that a temperature difference occurs between the circuits 1A, 1B, and 1C.

[0006] Then, there is a problem that it is difficult to obtain the original optical characteristics due to a temperature shift between the optical circuits 1A, 1B and 1C.

Accordingly, an object of the present invention is to provide a waveguide type optical module capable of reducing the temperature distribution in an optical waveguide element and controlling the temperature of optical circuits arranged at a plurality of locations to a uniform temperature. It is in.

[0008]

According to the first aspect of the present invention,
In a waveguide-type optical module having a temperature-dependent optical characteristic, wherein the temperature of an optical circuit arranged at a plurality of locations in the waveguide element is adjusted by using a heater, It is characterized in that the temperature of an optical circuit arranged in a place is adjusted by a plurality of heaters.

According to a second aspect of the present invention, in the first aspect, the plurality of heaters are electrically connected in parallel.

According to a third aspect of the present invention, in the first or second aspect, the plurality of heaters are fixed to a back surface of a package to which the waveguide element is fixed.

According to a fourth aspect of the present invention, in the first or second aspect, the plurality of heaters are formed on an optical circuit of a waveguide element.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the waveguide type optical module according to the present invention will be described below with reference to the accompanying drawings. The same parts as those in FIGS. 5 and 6 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 1 and FIG. 2, an optical fiber 2 is connected to a waveguide element 1. Inside the waveguide element 1, optical circuits 1A, 1B, and 1C, each of which requires a temperature adjustment, are formed at a plurality of different locations.

The waveguide element 1 includes a first package 9
The package 9 is adhered and fixed to the surface of
A plurality of heaters 3A and 3B described later are attached, and a temperature sensor 4 is attached to the surface of the waveguide element 1. The first package 9 is fixed to the second package 7 via the pedestal 6, and a space between the second package 7 and the first package 9 is filled with a heat insulating material 8,
Heat radiation from the waveguide element 1 and the first package 9 is prevented.

The electric power of the heaters 3A, 3B is supplied from the outside to the inside of the second package 7 through the electric interface 5, and from here, the electric power is supplied to the heaters 3A, 3B through the electric wiring 10.
3B.

In this embodiment, the heaters 3A and 3B are electrically connected in parallel inside the module, and the amount of heat generated by each heater is passively controlled by utilizing the temperature characteristics of its electric resistance. That is, each of the heaters 3A, 3A
When a constant voltage is applied to B, the electric resistance of the heater having a large temperature rise increases, the flowing current decreases, and as a result, the calorific value decreases.

The resistance value R (Ω) of the heater and the applied voltage E
(V) The relationship between the current I (A) is as follows: E = IR (T) (1) where T represents the temperature.

From the equation (1), the heat value H (W) is H = I ² · R (T) (2) Generally, the resistance value R (Ω) of the heater has a temperature dependency, The resistance value increases due to the rise. FIG. 4 shows the relationship between the temperature, the resistance value, and the heat value of a general heater. It can be seen that the resistance value increases with an increase in the temperature of the heater, and the calorific value decreases when a constant voltage is applied.

In this embodiment, the temperature control mechanism can be particularly optimized in the internal structure of the optical waveguide type optical module.

Since a plurality of heaters 3A, 3B are mounted on the back surface of the first package 9, each heater 3A, 3B
By controlling the heating, the temperature distribution of the waveguide element 1 can be made uniform, and as shown in FIG. 3, the temperatures of the optical circuits 1A, 1B, and 1C arranged at a plurality of different locations can be made substantially uniform. Can be.

Accordingly, the temperature deviation between the optical circuits 1A, 1B, and 1C is suppressed, and the original optical characteristics (such as crosstalk) can be obtained.

Since a plurality of heaters 3A and 3B are electrically connected in parallel, when a constant voltage is applied to these heaters, the amount of heat generated by the heaters is passively calculated according to the above-mentioned equations (1) and (2). Controlled. Therefore, the heater 3
The heat values of A and 3B are substantially equal, whereby the temperature deviation between the optical circuits 1A, 1B and 1C is further suppressed, and the original optical characteristics can be obtained.

In the present embodiment, it is desirable to use heaters having the same heater resistance value, and it is preferable that the heaters have large temperature dependence.

As described above, the present invention has been described based on one embodiment. However, the present invention is not limited to this, and various modifications can be made.

For example, in the above embodiment, a heater is attached to the back surface of the first package 9, but a heater may be formed on the surface of the waveguide element 1. The present waveguide-type optical module is mainly installed in an optical network of trunk lines, a wavelength multiplex transmission method of demultiplexing depending on the wavelength of the transmitted optical signal (: W avelength D ivision M ulti / demultiplexer, WD
It is a device suitable for use in M).

[0026]

According to the present invention, the temperature distribution of the waveguide element can be made uniform, and the temperatures of the optical circuits arranged at a plurality of locations can be made uniform. Therefore, good optical characteristics can be obtained, and the temperature characteristics can be kept small.

[Brief description of the drawings]

FIG. 1 is a top view showing one embodiment of a waveguide type optical module according to the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a schematic diagram showing a temperature distribution in the waveguide element.

FIG. 4 is a diagram showing the relationship between the temperature of a general heater and the resistance value / heat generation amount.

FIG. 5 is a top view showing an example of a conventional waveguide type optical module.

FIG. 6 is a side view of the same.

FIG. 7 is a schematic diagram showing a temperature distribution in a conventional waveguide element.

[Explanation of symbols]

 Reference Signs List 1 waveguide element 1A, 1B, 1C optical circuit 2 optical fiber 3A, 3B heater 4 temperature sensor 5 electric interface 6 pedestal 7 second package 8 heat insulating material 9 first package 10 electric wiring

Claims (4)

[Claims] 1. A waveguide type optical module having temperature dependent optical characteristics, wherein the temperature of optical circuits arranged at a plurality of locations in a waveguide element is adjusted by using a heater. 2. The waveguide type optical module according to claim 1, wherein the temperature of the optical circuits arranged at the plurality of locations is adjusted by a plurality of heaters. 2. The waveguide type optical module according to claim 1, wherein said plurality of heaters are electrically connected in parallel. 3. The waveguide type optical module according to claim 1, wherein the plurality of heaters are fixed to a back surface of the package to which the waveguide element is fixed. 4. The waveguide type optical module according to claim 1, wherein said plurality of heaters are formed on an optical circuit of a waveguide element.