JP4690646B2 - Optical apparatus and laser module having temperature controller - Google Patents

Description

The present invention relates to an optical transmitter used in the field of optical communication, and more particularly to a semiconductor laser device having a temperature controller using a Peltier element.

In the field of optical communication, as the distance increases and the amount of transmission increases, a more stable semiconductor laser device is required. As such a semiconductor laser device, a laser module equipped with a temperature controller using a Peltier element. There is. For example, as shown in FIG. 5, the laser module having such a temperature controller includes a laser element 10 and a light receiving element 20 that monitors light emission output from the laser element 10 mounted on a base 55, and includes an optical fiber 40. Stored in the package 100.
Laser modules with temperature controllers are often required to have high functionality, and laser modules that integrate many optical components such as wavelength monitor functions and optical modulators are being developed. Many optical components are densely mounted. Also, a laser module has been developed in which the temperature of the laser element can be varied by changing the temperature of the laser element by changing the temperature maintained by the temperature controller over a wide range.

In a laser module having such a temperature controller, a substrate (hereinafter referred to as a base) is laminated on the entire upper surface of the temperature controller, and optical components (laser element, lens, photodiode for detecting light quantity, wavelength filter, etc.) A base such as a holder or a substrate on which each is mounted is fixed on the base.
In general, a material having good thermal conductivity such as a copper tungsten alloy is used as the base material. On the other hand, a material suitable for the optical component to be mounted (for example, 50 alloy which is an iron-nickel alloy) is appropriately used for the mount on which the individual optical components are installed. When a material different from the constituent material of the base is selected as the material constituting the optical component base, the different material is bonded and fixed between the base and the optical part base.

JP 2000-58975 A

When the mount on which the optical component is mounted is made of a material having different physical properties such as a thermal expansion coefficient and a thermal conductivity, stress is generated due to a difference in expansion or contraction between the materials. In the optical component mount, since the optical axes of various optical components are adjusted and installed, the deformation of the mount causes a problem that the axis of the optical system of the optical component mounted on the mount is shifted. In particular, a metal material is likely to be deformed because it has a larger coefficient of thermal expansion and a larger elastic modulus than an inorganic material such as ceramic. For example, as shown in the figure, when the temperature of the gantry in which the metal B having a larger thermal expansion coefficient than the metal A is bonded to the metal A rises, the entire portion where the metal B is bonded to the metal A is on the metal B side. Deforms into a convex shape. When two optical components are installed on the metal substrate B and optically aligned, the optical axes of the two are shifted due to the deformation of the substrate B. Since the stress generated at such a joint surface propagates and accumulates according to the area, the larger the joint area, the larger the amount of stress and the greater the deformation amount.

In order to solve the above problems, the present invention is configured as follows.
The first invention is
A temperature controller;
A first substrate composed of a first material placed on a temperature controller;
A second substrate composed of a second material bonded onto the first substrate;
An optical component installed on the second substrate,
The coefficient of thermal expansion of the first material is greater than the coefficient of thermal expansion of the second material,
The first substrate has a U-shape with both ends protruding.
The second substrate is provided at both ends of the first substrate,
The optical device according to the present invention is characterized in that the second substrate is disposed so as not to come into contact with other members other than a joint surface between the first substrate and the optical component.

The second invention is in addition to the first invention,
The optical component is provided in a portion protruding from the temperature controller, and is related to an optical device.

The third invention is
A laser element;
A temperature controller;
A first substrate composed of a first material placed on a temperature controller;
A second substrate composed of a second material bonded onto the first substrate;
An optical component installed on the second substrate;
It has the laser element, the temperature controller, the first substrate, and a front Symbol package housing the second substrate and the optical component,
The coefficient of thermal expansion of the first material is greater than the coefficient of thermal expansion of the second material,
The first substrate has a U-shape with both ends protruding.
The second substrate is provided at both ends of the first substrate,
In the invention according to the laser module, the second substrate is disposed so as not to come into contact with other members other than a joint surface between the first substrate and the optical component.

The fourth invention, in addition to the third invention,
The optical component is an invention according to a laser module, wherein the optical component is provided in a portion protruding from the temperature controller.

With the optical device according to the present invention, it is possible to provide an optical device that is temperature-controlled on a temperature regulator and has little optical axis deviation due to thermal expansion or the like.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each figure schematically shows each component and its function to the extent that the present invention can be understood, and does not limit the present invention.
A metal substrate A which is a first substrate is mounted on a temperature controller using a Peltier element, and a second substrate and a third substrate made of a metal substrate B are bonded to the metal substrate A on the metal substrate A, respectively. Yes. When the temperature is changed by the temperature controller, the metal substrate A and the metal substrate B have different thermal expansion coefficients or thermal conductivities and the like, and have different amounts of expansion or contraction due to temperature changes. For example, when the temperature rises when the thermal expansion of the metal A is larger than that of the metal B, the metal A deforms as shown in FIG.
However, the metal substrate B, which is the second substrate, is divided into a plurality of members and bonded to the metal substrate A, which is the first substrate, and a gap is provided around the side surface of the second substrate to directly connect with other components and substrates. By arranging them so that they do not contact each other, the stress generated at each joint surface is dispersed, and the amount of deformation of each is smaller than when the second substrate is integrally formed or in contact with each other. Get smaller.

First embodiment Fig. 2 is a schematic plan view of a laser module showing the first embodiment, and Fig. 3 shows an optical device installed on a temperature controller housed in a laser module package. It is a perspective view. Laser light output from the front end face of the laser element 10 is coupled to the optical fiber 40 by the lens 30 and conveyed to the outside of the package 100, and laser light output from the rear end face of the laser element 10 is received by the light receiving element (PD) 20. Light is received and the amount of light output from the laser element 10 is monitored. The laser element 10 and the light receiving element 20 are attached to the laser carrier 11 and the PD carrier 25, respectively, and are mounted on a base 51 (first substrate) installed on a temperature controller 50 made of a Peltier element. The base 51 and the PD carrier 21 are made of a copper tungsten alloy, and the laser carrier 11 is made of aluminum nitride.
The lens 30 is attached to a lens holder 31 including members 31-a (second substrate), 31-b (second substrate), and 31-c (third substrate) and is installed on the base 51. . The lens holder 31 is made of an iron-nickel alloy 50 alloy, which is a material having a lower thermal conductivity than the base 51 or the like, and the lens holder members 31-a and 31-b are made of a copper tungsten alloy by solder or the like. 51 is joined. The lens holder members 31-a and 31-b are arranged so as not to come into contact with other components except for the joint surface with the base 51 and the joint surface with the lens holder member 31-c mounted on the upper part. As described above, the lens holder 31 is joined to the other constituent members such as the base 51 by the divided members 31-a and 31-b, so that the temperature change at the joint surface with the other constituent members. It is possible to disperse the stress caused by the above and reduce the deformation of each member.

Second Embodiment The second embodiment is a laser module having the same configuration as that of the first embodiment shown in FIG. 2 except that a base 51 (first substrate) mounted on the temperature controller 50 is used. The shape is different. FIG. 4 is a perspective view showing an optical device installed on a temperature controller in the laser module of the second embodiment.
In the present embodiment, the base 51 has a U-shape, and the lens holders 31-a and 31-b are mounted on both end portions where the base 51 protrudes. In addition to the lens holder 31, the base 51 is also divided so that the stress generated on the joint surfaces of the lens holder members 31-a and 31-b can be more reliably prevented from propagating through the base 51. The amount of deformation can be suppressed.
In addition, since the lens holder 31 is mounted on a portion of the base 51 mounted on the temperature controller that protrudes from the temperature controller, the lens 30 and the lens holder 31 are not easily affected by the temperature controller 50. It has become. Therefore, even when the temperature controller makes a sudden temperature change for control, the temperature fluctuation is small and the structure is less likely to be deformed.
Furthermore, the thickness of the base 51 and the lens holder members 31-a and 31-b when mounted on the temperature controller 50 is adjusted for the size of the package 100 and the optical axis of the laser element 10 and the optical fiber 40. However, in the case of the configuration as in the second embodiment, the base 51 and the lens holder members 31-a and 31-b may be thickened. By increasing the thickness of the metal substrate to be bonded, the amount of deformation can be reduced.

Third Embodiment FIG. 5 is a schematic plan view of a laser module showing a third embodiment, and FIG. 6 is a schematic side view.
The laser module shown in the third embodiment is a wavelength tunable laser module that makes the wavelength of the laser light variable by changing the temperature of the laser element 10.
Laser light output from the front end face of the laser element 10 is converted into parallel light by the lens 30, passes through the isolator 41, and is branched by the optical branching device 42. One branched light is received by the light receiving element 21, the other branched light is further branched by the optical branching device 43, and one branched light is transmitted by the optical wavelength filter 44 and then received by the light receiving element 22. The other branched light is guided to the optical fiber 40.
The lens 30, the isolator 41, the optical branching units 42 and 43, the optical wavelength filter 44, and the light receiving elements 20 and 21 are bonded to a base 51 installed on the second substrate 53 and installed on the temperature controller 50. The laser element 10 is attached to the laser carrier 11 and mounted on the small temperature controller 52, and is installed on a substrate 54 made of a copper tungsten alloy, which is the same material as the base 51 joined on the base 51. The laser element 10 is temperature-controlled differently from other optical components by a small temperature controller 52, and the emission wavelength is controlled. The substrate 53 sandwiched between the temperature controller 50 and the small temperature controller 52 is placed in a different temperature environment from the base 51 or the second substrate, and exhibits different expansion or contraction behavior. The substrate 53 and the substrate 54 are arranged so as to have a gap so that the stress does not affect each other and are not in contact with other components, so that deformation can be suppressed.
In the present embodiment, the substrate 54 and the base 51 are configured to join different members. However, since they are formed of the same material, the substrate 53 and the gap are disposed even if the integrally formed member is used. By doing so, the same effect can be obtained.

Fourth embodiment The fourth embodiment is a laser module having substantially the same configuration as that of the third embodiment, except that the base 51 (first substrate) mounted on the temperature controller 50 is used. The shape is different.
FIG. 7 is a perspective view of the base 51 installed on the temperature controller in the laser module of the fourth embodiment.
In the present embodiment, the thick portions 55 in the direction parallel to the optical axis direction until the laser light is propagated from the laser element to the optical fiber are provided on both side portions of the base 51.
In a laser module in which many optical components are mounted on a temperature controller as in this embodiment, a plurality of optical components are installed on one substrate in advance, and then the manufacturing process is performed by mounting on the temperature controller. It becomes easy. However, in a substrate on which a plurality of optical components are arranged, there is a case where deformation due to its own stress cannot be ignored even if the influence of stress from the surrounding substrate is eliminated. In this embodiment, an optical component is not mounted, and a portion that can be freely designed within a range in which the thickness of the base 51 can be accommodated in the package 100 is made thick, and the deformation of the base 51 is further suppressed by increasing the rigidity. is there. The thick part is effective in any part, but it is desirable to mount the optical component in the central part and provide it on both sides. In particular, since suppressing deformation in the optical axis direction is effective in suppressing optical axis deviation, the thick portion should be parallel to the optical axis direction until the laser light propagates from the laser element to the optical fiber. It is desirable to provide it.
In FIG. 7, the thick portions at both ends of the base 51 are formed so as to rise upward. However, if there is a portion where the base 51 protrudes from the temperature controller 50, the portions may be thickened downward. Moreover, you may form a thick part by joining the member comprised with the same material.

As described above, in the optical device and the laser module having the temperature controller according to the present invention,
Deformation of the gantry combining different materials on the temperature controller can be suppressed.

It is a figure which shows the deformation | transformation in the board | substrate which combined the dissimilar material. It is a side surface schematic diagram of the laser module concerning 1st Embodiment. It is a perspective view of the laser module concerning a 1st embodiment. It is a perspective view of the laser module concerning 2nd Embodiment. It is a plane schematic diagram of the laser module concerning 3rd Embodiment. It is a side surface schematic diagram of the laser module concerning 3rd Embodiment. It is a perspective view of the base 51 used for the laser module concerning 4th Embodiment.

Explanation of symbols

10: Laser element 11: Laser carrier 20: Light receiving element 21: Light receiving element 22: Light receiving element 25; PD carrier 30: Lens 31: Lens holder 40: Optical fiber 41: Isolator 42: Optical branching device 43: Optical branching device 44: Optical wavelength filter 50: temperature controller 51: base 52: small temperature controller 53: first substrate 54: second substrate 55: base thick portion 100: package

Claims (4)

A temperature controller and a first substrate composed of a first material installed on the temperature controller;
A second substrate composed of a second material bonded onto the first substrate;
An optical component installed on the second substrate,
The coefficient of thermal expansion of the first material is greater than the coefficient of thermal expansion of the second material,
The first substrate has a U-shape with both ends protruding.
The second substrate is provided at both ends of the first substrate,
The optical device, wherein the second substrate is disposed so as not to contact other members except for a joint surface between the first substrate and the optical component. The optical device according to claim 1, wherein the optical component is provided in a portion protruding from the temperature controller. A laser element;
A temperature controller;
A first substrate composed of a first material placed on a temperature controller;
A second substrate composed of a second material bonded onto the first substrate;
An optical component installed on the second substrate;
It has the laser element, the temperature controller, the first substrate, and a front Symbol package housing the second substrate and the optical component,
The coefficient of thermal expansion of the first material is greater than the coefficient of thermal expansion of the second material,
The first substrate has a U-shape with both ends protruding.
The second substrate is provided at both ends of the first substrate,
The laser module, wherein the second substrate is disposed so as not to come into contact with other members other than a joint surface between the first substrate and the optical component. The laser module according to claim 3, wherein the optical component is provided in a portion protruding from the temperature controller.

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