JP2007005681A - Semiconductor laser module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor laser module in which a temperature sensor catches a less influence of ambient temperature even when its package is compact, and a temperature dependency of oscillation wavelength of the semiconductor laser device can be suppressed less. <P>SOLUTION: An semiconductor laser module 10 includes a semiconductor laser device 6, a base 4 mounting the semiconductor laser device, a temperature sensor 7 arranged close to the semiconductor laser device on the base for detecting a temperature of the semiconductor laser device, and a package 2 housing the base and temperature sensor. The module 10 drives the semiconductor laser device while keeping a designated temperature with a Peltier element 3 based on a temperature detected with the temperature sensor. Furthermore, a shield 8 for shielding thermal transmission through a sealing gas within the package in a space between a package wall surface 2d closest to the temperature sensor 7 and temperature sensor 7 is arranged in the base between the temperature sensor and package. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor laser module.

  Conventionally, a semiconductor laser module used as a signal light source has a temperature sensor such as a thermistor placed near the semiconductor laser element in order to stabilize the oscillation wavelength by suppressing fluctuations in the oscillation wavelength due to changes in environmental temperature. The semiconductor laser element is adjusted to a predetermined temperature by controlling the operation of temperature adjusting means such as a Peltier element based on the measured temperature. In particular, a distributed feedback type semiconductor laser module used as a signal light source for wavelength division multiplexing (DWDM) transmission uses a material, area, and thickness of a heat sink and a thermistor substrate in order to suppress fluctuations in oscillation wavelength with changes in environmental temperature. By making the selection, the temperature of the semiconductor laser element and the temperature of the temperature sensor are matched (for example, see Patent Document 1).

JP 2001-244545 A

  Incidentally, in recent years, semiconductor laser modules have been promoted to reduce the size of the package to 1/4 of the conventional size, and a small package having a side of about 5 mm has been developed. An example of such a semiconductor laser module is shown in FIGS. As shown in FIGS. 9 and 10, the semiconductor laser module 1 has a main body 2a and a lid 2b, and a temperature adjusting means such as aluminum nitride (Peltier element 3) is provided in a package 2 filled with nitrogen gas. A base 4 made of (AlN) is provided, and a plurality of leads 2c are provided outside the main body 2a. The base 4 is mounted with a semiconductor laser element 6 via a submount 5 made of aluminum nitride disposed in the center, and a temperature of a thermistor or the like for monitoring the temperature of the semiconductor laser element 6 is provided on the side wall 2d side in the vicinity of the semiconductor laser element 6. A sensor 7 is provided. The base 4 has a photodiode 12 mounted in the vicinity of the semiconductor laser element 6 via a carrier 11. The Peltier element 3 adjusts the temperature of the semiconductor laser element 6 mounted on the base 4 via the base 4 based on a signal from the temperature sensor 7. The package 2 is provided with a chip inductor 8 which constitutes a part of the electric circuit of the semiconductor laser element 6 inside, and a lens holder 9 holding a lens 9a is attached to the side wall 2e on the laser light emission side. .

  As shown in FIG. 10, the semiconductor laser module 1 includes a package 2 having a width W = 4 mm and a height Ht = 5 mm, and the volume of the package 2 is as small as ¼ or less of the conventional one. The distance L1 to the nearest side wall 2d is only 0.5 mm, and the temperature sensor 7 and the side wall 2d are very close compared to the conventional large package. At this time, the heat generally decays exponentially with respect to the conduction distance, but the semiconductor laser module 1 is very close to the distance L1 between the temperature sensor 7 and the nearest side wall 2d, during which nitrogen gas flows. Existing. For this reason, the semiconductor laser module 1 easily conducts heat through the nitrogen gas between the side wall 2d closest to the temperature sensor 7 and the temperature sensor 7, and is easily affected by the environmental temperature. For example, when the semiconductor laser module 1 is placed in a high temperature environment, the heat H outside the package 2 is conducted to the temperature sensor 7 through the nitrogen gas as indicated by the dotted line, so that the temperature of the semiconductor laser element 6 is accurately monitored. It is difficult. Therefore, when the semiconductor laser module 1 is used in an environment where the temperature difference between the inside and outside of the package is large, the temperature detected by the temperature sensor 7 is higher or lower than the temperature of the semiconductor laser element 6, and the semiconductor laser element is based on such temperature. As a result of adjusting the temperature of 6, there was a problem that the oscillation wavelength fluctuated.

  The present invention has been made in view of the above-described problems, and even in a small package, the temperature sensor is hardly affected by the environmental temperature, and the temperature dependence of the oscillation wavelength of the semiconductor laser element is suppressed to be small. An object of the present invention is to provide a semiconductor laser module capable of satisfying the requirements.

  In order to solve the above-described problems and achieve the object, a semiconductor laser module of the present invention is disposed in the vicinity of a semiconductor laser element, a base on which the semiconductor laser element is mounted, and the semiconductor laser element on the base, A temperature sensor that detects a temperature of the semiconductor laser element; and a package that accommodates the base and the temperature sensor. The semiconductor laser element is controlled to a predetermined temperature by a temperature adjusting unit based on the temperature detected by the temperature sensor. A semiconductor laser module that is driven while adjusting, wherein a blocking portion that blocks heat conduction via a sealing gas in the package between the package wall surface closest to the temperature sensor and the temperature sensor It is provided in the base between the temperature sensor and the package.

  According to a second aspect of the present invention, in the semiconductor laser module according to the second aspect of the invention, the blocking unit includes a circuit component that constitutes an electric circuit of the semiconductor laser element, a light receiving component that monitors laser light emitted from the semiconductor laser element, Alternatively, it is a structural component mounted on the base on the package wall surface side closest to the temperature sensor, including at least one optical component constituting an optical system for deriving the laser light out of the package. To do.

  According to a third aspect of the present invention, in the semiconductor laser module according to the first aspect of the invention, the blocking portion is higher than the temperature sensor and includes a blocking wall formed on the base on the package wall surface side closest to the temperature sensor. It is characterized by including.

  According to a fourth aspect of the present invention, in the semiconductor laser module according to the present invention, the blocking portion is a wall formed on the package wall surface closest to the temperature sensor by a concave portion in which the temperature sensor is provided on the base. It is characterized by including.

  In the semiconductor laser module according to the present invention, the temperature sensor and the package include a blocking portion that blocks heat conduction through the sealing gas in the package between the package wall surface closest to the temperature sensor and the temperature sensor. The temperature sensor is hardly affected by the environmental temperature even in a small package, and the temperature dependency of the oscillation wavelength of the semiconductor laser element can be suppressed to a small level.

(Embodiment 1)
Hereinafter, a first embodiment of the semiconductor laser module of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view of a semiconductor laser module according to a first embodiment of the semiconductor laser module of the present invention, with a package lid removed. FIG. 2 is a cross-sectional view taken along line C1-C1 of the semiconductor laser module shown in FIG. Here, in the semiconductor laser module according to each embodiment of the present invention described below, the same components as those of the conventional semiconductor laser module shown in FIGS. 9 and 10 are denoted by the same reference numerals.

  As shown in FIGS. 1 and 2, the semiconductor laser module 10 has a semiconductor laser element 6 mounted on the center of the base 4 via a submount 5 and a chip inductor 8 mounted on the side wall 2d side. The base 4 has a photodiode 12 mounted on the rear side of the submount 5 as seen from the laser beam emission direction via a carrier 11, and a temperature surrounded by the semiconductor laser element 6, the chip inductor 8 and the carrier 11. A sensor 7 is arranged. At this time, as shown in FIG. 2, the semiconductor laser module 10 has a width W of the package 2 of 4 mm or less, a height Ht of 5 mm or less, and a distance L2 between the side wall 2d closest to the temperature sensor 7 and the chip inductor 8 is set to 0. The height of the chip inductor 8 was set higher than that of the temperature sensor 7.

  In the semiconductor laser module 10, since the chip inductor 8 is disposed between the temperature sensor 7 and the side wall 2d closest to the temperature sensor 7, the temperature sensor 7 is connected to the temperature sensor 7 through the nitrogen gas sealed in the package 2. The conduction of heat H is interrupted by the chip inductor 8 and the heat H conducted to the chip inductor 8 flows to the base 4 cooled by the Peltier element 3, so that the temperature between the temperature sensor 7 and the semiconductor laser element 6. Temperature gradient is kept small. For this reason, even if the semiconductor laser module 10 is used in an environment where the temperature difference between the inside and outside of the package is large, the temperature sensor 7 is hardly affected by the environmental temperature and can accurately monitor the temperature of the semiconductor laser element 6. Can do. Therefore, in the semiconductor laser module 10, even if the package 2 is small, the temperature sensor 7 is not easily affected by the environmental temperature, and the temperature dependence of the oscillation wavelength of the semiconductor laser element 6 can be suppressed to a low level.

  Here, in the semiconductor laser module 10, the operating current is controlled under the ambient temperature of 20 ° C., 40 ° C., 60 ° C., and 80 ° C. while controlling the Peltier element 3 so that the temperature detected by the temperature sensor 7 is 45 ° C. When the semiconductor laser device 6 was driven at Iop = 30 mA and the relationship between the environmental temperature (° C.) and the oscillation wavelength λ (nm) was measured, the result indicated by the straight line A in FIG. 3 was obtained. The temperature dependency Δλ / ΔT of the oscillation wavelength with respect to the environmental temperature of 20 to 80 ° C. in the semiconductor laser module 10 was calculated from the straight line A in FIG. 3 and found to be Δλ / ΔT = −0.38 pm / ° C.

  On the other hand, using the conventional semiconductor laser module 1 shown in FIG. 9 and FIG. 10 having the same package 2 dimensions and no blocking part, the ambient temperature (° C.) and the oscillation wavelength λ (nm) under the same driving conditions. As a result, the result indicated by the straight line B in FIG. 3 was obtained. The temperature dependency Δλ / ΔT of the oscillation wavelength was calculated in the same manner for the semiconductor laser module 1 from the straight line B in FIG. 3, and was found to be Δλ / ΔT = −0.9 pm / ° C. At this time, in the semiconductor laser module 1 without the blocking part, the arrangement of the temperature sensor 7 on the base 4 has been variously changed. However, since there is no blocking part, no matter where the temperature sensor 7 is arranged, the heat does not generate nitrogen gas. Conducting as a conductive medium, the temperature dependence of the oscillation wavelength was not improved.

  Therefore, the semiconductor laser module 10 includes the temperature sensor 7 and the package 2 as the chip inductor 8 serving as a blocking portion that blocks conduction of heat H transmitted from the side wall 2d to the temperature sensor 7 through the nitrogen gas sealed in the package 2. It was found that the temperature dependence of the oscillation wavelength was greatly improved and the temperature dependence was kept small compared to the semiconductor laser module 1 having the same package 2 dimensions.

(Embodiment 2)
Next, a second embodiment of the semiconductor laser module of the present invention will be described in detail with reference to the drawings. In the semiconductor laser module of the first embodiment, the chip inductor 8 which is a circuit component constituting a part of the electric circuit of the semiconductor laser element 6 is used as the cutoff part. However, the semiconductor laser module of the second embodiment further includes a laser. Optical components that constitute an optical system that guides light out of the package 2 are used. 4 is a plan view of a semiconductor laser module according to a second embodiment of the semiconductor laser module of the present invention, with a package lid removed.

  As shown in FIG. 4, the semiconductor laser module 15 includes a semiconductor laser element 6 mounted on the base 4 via a submount 5, a chip inductor 8 mounted on the side wall 2d side, and a photo mounted via a carrier 11. In addition to the diode 12, a lens holder 16 holding a lens 16 a is installed between the semiconductor laser element 6 and the lens holder 9, and a portion surrounded by the semiconductor laser element 6, the chip inductor 8, the carrier 11 and the lens holder 16. A temperature sensor 7 is disposed on the surface. The lens holder 16 blocks heat conducted from the lens holder 9 side to the temperature sensor 7 through nitrogen gas.

  The semiconductor laser module 15 blocks the conduction of heat transmitted from the side wall 2d to the temperature sensor 7 via the nitrogen gas sealed in the package 2 by the chip inductor 8, and as shown by a dotted line in FIG. The conduction of heat transmitted from the side to the temperature sensor 7 is blocked by the lens 16a which is an optical component. For this reason, in the semiconductor laser module 15, since the temperature sensor 7 is less susceptible to the influence of the environmental temperature than the semiconductor laser module 10 of the first embodiment, the temperature dependence of the oscillation wavelength of the semiconductor laser element 6 is reduced. The laser module 1 can be kept smaller.

(Embodiment 3)
Next, a third embodiment of the semiconductor laser module of the present invention will be described in detail with reference to the drawings. In the semiconductor laser module of the first embodiment, the chip inductor 8 which is a circuit component that constitutes a part of the electric circuit of the semiconductor laser element 6 is used as the cutoff part. However, the semiconductor laser module of the third embodiment has the cutoff part. A barrier wall provided on the base is used. FIG. 5 shows a third embodiment of the semiconductor laser module of the present invention, and is a plan view of the semiconductor laser module with the package lid removed. FIG. 6 is a cross-sectional view taken along line C2-C2 of the semiconductor laser module shown in FIG.

  5 and 6, the semiconductor laser module 20 includes a temperature sensor in addition to the semiconductor laser element 6 mounted on the base 4 via the submount 5 and the photodiode 12 mounted via the carrier 11. 7 is formed integrally with the base 4 on the side wall 2d side and the lens holder 9 side, and the temperature sensor 7 is arranged in a portion surrounded by the cutoff wall 4a, the semiconductor laser element 6 and the carrier 11. Yes. The lens holder 16 blocks heat conducted from the lens holder 9 side to the temperature sensor 7 through nitrogen gas. The blocking wall 4a has a height between the height of the temperature sensor 7 and the lid 2b of the package 2, and blocks heat conducted from the side wall 2d and the lens holder 9 side to the temperature sensor 7 through nitrogen gas.

  In addition to the heat H (see FIG. 6) transmitted from the side wall 2d to the temperature sensor 7 through the nitrogen gas sealed in the package 2, the semiconductor laser module 20 has a lens holder 9 side as shown in FIG. The conduction of heat transmitted to the temperature sensor 7 is blocked by the blocking wall 4a. For this reason, in the semiconductor laser module 20, as with the semiconductor laser module 15 of the second embodiment, the temperature sensor 7 is not easily affected by the environmental temperature, so that the temperature dependency of the oscillation wavelength of the semiconductor laser element 6 is reduced. It can be kept smaller than the semiconductor laser module 1.

  In the third embodiment, the blocking wall 4a is L-shaped and disposed on the side wall 2d side and the lens holder 9 side as shown in FIG. However, in the first embodiment (see FIG. 1), when the structural component (chip inductor 8) is provided only on the side wall 2d side, it is closest to the temperature sensor 7 in view of the effect of the present invention. It is obvious that the blocking wall 4a may be provided only on the side wall 2d side.

(Embodiment 4)
Next, a fourth embodiment of the semiconductor laser module of the present invention will be described in detail with reference to the drawings. In the semiconductor laser module of the first embodiment, the chip inductor 8 which is a circuit component that constitutes a part of the electric circuit of the semiconductor laser element 6 is used as the cutoff unit. However, the semiconductor laser module of the fourth embodiment has the cutoff unit. A wall formed by a recess provided in the base is used. FIG. 7 shows a fourth embodiment of the semiconductor laser module of the present invention, and is a plan view of the semiconductor laser module with the package lid removed. FIG. 8 is a cross-sectional view taken along line C3-C3 of the semiconductor laser module shown in FIG. 7 with a lid attached to the package.

  As shown in FIGS. 7 and 8, the semiconductor laser module 25 includes a temperature sensor in addition to the semiconductor laser element 6 mounted on the base 4 via the submount 5 and the photodiode 12 mounted via the carrier 11. A concave portion 4 b in which the temperature sensor 7 is disposed is formed on the side of the wall surface 2 d closest to 7. As shown in FIG. 8, the concave portion 4b is formed deeper than the temperature sensor 7, and the wall 4c formed on the side of the wall surface 2d closest to the temperature sensor 7 is connected to the temperature sensor 7 via the nitrogen gas from the side wall 2d. The heat H conducted to is cut off.

  In the semiconductor laser module 25, by disposing the temperature sensor 7 in the recess 4b of the base 4, the conduction of heat transmitted from the side wall 2d to the temperature sensor 7 through the nitrogen gas sealed in the package 2 is transferred to the wall 4c of the recess 4b. In addition to blocking by the recess 4b, conduction of heat transmitted from the lens holder 9 to the temperature sensor 7 is blocked by the recess 4b. For this reason, in the semiconductor laser module 25, the temperature sensor 7 is not easily affected by the environmental temperature, like the semiconductor laser modules 15 and 20, so that the temperature dependence of the oscillation wavelength of the semiconductor laser element 6 is reduced. It can be kept smaller than 1.

1 is a plan view of a semiconductor laser module according to a first embodiment of the semiconductor laser module of the present invention, with a package lid removed. FIG. FIG. 2 is a cross-sectional view taken along line C1-C1 of the semiconductor laser module shown in FIG. 1 with a lid attached to a package. It is a temperature characteristic figure of the oscillation wavelength which shows the relationship between the environmental temperature measured about the semiconductor laser module of this invention, and the conventional semiconductor laser module, and an oscillation wavelength. FIG. 7 is a plan view of a semiconductor laser module according to a second embodiment of the semiconductor laser module of the present invention, with a package lid removed. FIG. 7 is a plan view of a semiconductor laser module according to a third embodiment of the semiconductor laser module of the present invention, with a package lid removed. FIG. 6 is a cross-sectional view taken along the line C2-C2 of the semiconductor laser module shown in FIG. 5 with a lid attached to the package. FIG. 24 is a plan view of a semiconductor laser module according to a fourth embodiment of the semiconductor laser module of the present invention, with a package lid removed. FIG. 8 is a cross-sectional view taken along line C 3 -C 3 of the semiconductor laser module shown in FIG. 7 with a lid attached to the package. An example of a conventional semiconductor laser module is a plan view of a semiconductor laser module with a package lid removed. FIG. 10 is a cross-sectional view taken along line C 3 -C 3 of the semiconductor laser module shown in FIG. 9 with a lid attached to the package.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Semiconductor laser module 2 Package 2a Main body 2b Cover 2d Side wall 3 Peltier element 4 Base 4a Blocking wall 4b Recessed part 4c Wall 5 Submount 6 Semiconductor laser element 7 Temperature sensor 8 Chip inductor 9 Lens holder 9a Lens 11 Carrier 12 Photo diode 15 Semiconductor laser Module 16 Lens holder 16a Lens 20, 25 Semiconductor laser module

Claims (4)

A semiconductor laser element;
A base on which the semiconductor laser element is mounted;
A temperature sensor disposed in the vicinity of the semiconductor laser element on the base and detecting a temperature of the semiconductor laser element;
A package containing the base and the temperature sensor;
A semiconductor laser module that drives the semiconductor laser element while adjusting the semiconductor laser element to a predetermined temperature by temperature adjusting means based on the temperature detected by the temperature sensor,
Provided in the base between the temperature sensor and the package is a blocking portion that blocks heat conduction through the sealing gas in the package between the package wall surface closest to the temperature sensor and the temperature sensor. A semiconductor laser module.   The blocking section is a circuit component that constitutes an electric circuit of the semiconductor laser element, a light receiving component that monitors laser light emitted from the semiconductor laser element, or an optical system that constitutes an optical system that guides the laser light out of the package. The semiconductor laser module according to claim 1, wherein the semiconductor laser module is a structural component mounted on the base on the package wall surface closest to the temperature sensor, including at least one of the components.   2. The semiconductor laser module according to claim 1, wherein the blocking part includes a blocking wall formed on the base on the package wall surface side that is higher than the temperature sensor and closest to the temperature sensor.   4. The semiconductor laser according to claim 1, wherein the blocking portion includes a wall formed on a side of the package wall surface closest to the temperature sensor by a recess in which the temperature sensor is provided on the base. 5. module.

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