WO2009155894A1

WO2009155894A1 - Semiconductor laser module

Info

Publication number: WO2009155894A1
Application number: PCT/DE2009/000729
Authority: WO
Inventors: Roland Schulz; Karsten Auen; Thomas Schwarz
Original assignee: Osram Opto Semiconductors Gmbh
Priority date: 2008-06-25
Filing date: 2009-05-20
Publication date: 2009-12-30
Also published as: DE102008030254A1

Abstract

A semiconductor laser module is specified, having - a module mount (10) with a mounting surface (11), - a pump apparatus (1) which is arranged on the mounting surface (11), - a surface-emitting semiconductor laser (40) which is arranged on the mounting surface (11), and - a frequency conversion apparatus (6) which is arranged on the mounting surface (11), wherein - one and only one optical element (2) is located in the beam path of the pump beam (1c) between the pump apparatus and the surface-emitting semiconductor laser (40), and wherein - radiation passage surfaces (23,24) of the optical element are adjacent to air.

Description

description

Semiconductor laser module

A semiconductor laser module is specified.

The document EP 1125350 describes a semiconductor laser module.

One problem to be solved is to

Specify semiconductor laser module, which has very few individual components. Another object to be solved is to specify a particularly compact semiconductor laser module.

According to at least one embodiment of the

Semiconductor laser module, the semiconductor laser module includes a module carrier. The module carrier is, for example, a connection carrier made of DBC (Direct Bonded Copper) or a connection carrier with a

Base body of electrically insulating material, on the surface of which metallizations are applied in places, which serve for the mechanical attachment and the electrical connection of components of the semiconductor laser module.

The module carrier has a mounting surface. The mounting surface is given by a part of the surface of the module carrier. For example, the mounting surface is formed by the top surface of the module carrier.

In accordance with at least one embodiment of the semiconductor laser module, a pump device is arranged on the mounting surface. The pump device comprises for example, a pump beam source such as an edge emitting semiconductor laser chip or a wide stripe laser. Furthermore, the pumping device comprises a mounting block for the pumping device, on which the pumping beam source is applied. The mounting block forms, for example, a heat sink for the pump beam source. The mounting block can be arranged between the mounting surface of the module carrier and the pump beam source. For example, the mounting block is applied to the mounting surface of the module carrier, the pump beam source is then on the

Mounting support facing away from the mounting block applied. The pumping device may be soldered or glued to the mounting surface of the module carrier.

According to at least one embodiment of the

Semiconductor laser module, the semiconductor laser module comprises a surface emitting semiconductor laser. The surface emitting semiconductor laser, for example, includes a mounting block for the superficial ^{'enemittierenden} semiconductor laser and at least one semiconductor laser chip, which is attached to the mounting block. The at least one semiconductor laser chip is preferably optically pumpable by the pump source of the pump device. The surface-emitting semiconductor laser is preferably mechanically firmly connected to the mounting surface of the module carrier. For this purpose, the surface-emitting semiconductor laser can be soldered or glued to the mounting surface.

According to at least one embodiment of the

Semiconductor laser module, the semiconductor laser module, a frequency conversion device, which is arranged on the mounting surface. The frequency conversion device comprises preferably an optically nonlinear crystal, which is used for frequency multiplication, for example for

Frequency doubling, which is suitable and provided by him passing laser radiation. The frequency conversion device is fixed mechanically fixed on the mounting surface of the module carrier. It can be soldered or glued there.

In accordance with at least one embodiment of the semiconductor laser module, exactly one optical element is located in the beam path of the pump beam between the pump device and the surface-emitting semiconductor laser. That is, in the beam path between the pumping device and surface emitting semiconductor laser, a single optical element is arranged. In particular, there are no further optically focusing elements for the pump radiation in this beam path. Furthermore, there are no optical elements in the beam path of the pump beam, which are provided for beam deflection or pumping beam raising or pumping beam reduction.

According to at least one embodiment of the

Semiconductor laser device border the

Radiation passage surfaces of the optical element in air. That is, the optical element has at least two

Radiation transmission areas. By the one

Radiation passage area enters pumping radiation into the optical element, through the other

Radiation passage area leaves the pump radiation, the optical element. When passing through the

Radiation passage surfaces, the pump light is optically influenced, for example, focused. For example, the pump beam source is not connected to the optical element by means of a fiber optic, but the radiation passage areas of the optical element are adjacent to air and are freely accessible. That is, when passing through the radiation passage surfaces occurs

Pumping radiation first of air in the optically denser material of the optical element and after passing through the optical element of optically denser material of the optical element in the optically thinner material, that is in air. The fact that the radiation passage surfaces adjoin air advantageously leads to the fact that due to the high refractive index jump, a particularly strong focusing of the penetrating pump radiation can be achieved. The disadvantage may be that losses due to total reflection occur at the radiation passage surfaces.

According to at least one embodiment of the

Semiconductor laser module, the semiconductor laser module on a module carrier, which comprises a mounting surface. Furthermore, the semiconductor laser module has a pumping device which is arranged on the mounting surface. Moreover, the semiconductor laser module includes a surface emitting semiconductor laser disposed on the mounting surface and a frequency conversion device mounted on the surface

Mounting surface is arranged. In the beam path of the pumping beam between the pumping device and the surface emitting semiconductor laser is exactly one single optical element. The radiation passage surfaces of the optical element are bounded by air.

The semiconductor laser module described here is based inter alia on the idea that with a single optical Airborne element, the optical tasks of multiple optical elements can be adopted, so that reduces the number of optical elements in the semiconductor laser module. This also leads to a reduced production of the semiconductor laser module

Assembly effort, since only a single optical element in the beam path of the pump beam source must be adjusted.

In accordance with at least one embodiment of the semiconductor laser module, the optical element comprises two crossed cylindrical lenses, wherein the optical element is formed in one piece. Under crossed cylindrical lenses are understood cylindrical lenses which are transverse, for example, perpendicular to each other. That is, the cylindrical lenses have a main extension direction in the direction of the longitudinal axis of the cylindrical lenses. The main directions of extension of the two crossed cylindrical lenses can, for example, be perpendicular to one another. The two cylindrical lenses are integrated into a single optical element.

This can be achieved, for example, in that a radiation passage area of the optical element is curved at least in places in the manner of the first cylindrical lens, another radiation passage area of the optical

Elements is then formed at least in places in the manner of a second cylindrical lens.

The optical element can be made of glass, a semiconductor material or a plastic, for example. For example, the optical element has a refractive index of at least 1.8 at a wavelength of 808 nanometers. In accordance with at least one embodiment of the semiconductor laser module, a second cylindrical lens of the optical element extends in directions perpendicular to the mounting surface. That is, the second cylindrical lens is arranged such that its main extension direction is perpendicular to the mounting surface of the module carrier. The first cylindrical lens of the optical element is then arranged to extend in directions parallel to the mounting surface. That is, the

Hauptersteckungsrichtung the first cylindrical lens extends in a plane which is parallel to the mounting surface.

The first and the second cylindrical lens are arranged in this way perpendicular to each other. Furthermore, the

Cylindrical lenses preferably also perpendicular to the pump radiation. One of the cylindrical lenses can be suitable for fast axis collimation. This cylindrical lens then focuses the pump radiation, for example, in directions which are perpendicular to the mounting surface. The focusing lens may be the first cylindrical lens.

The second cylindrical lens then focuses the pump radiation in the direction parallel to the mounting surface and serves for the so-called slow axis collimation. Overall, the optical effect

Focusing element in this way for the pump radiation and directs a pump beam on the surface emitting semiconductor laser, wherein the pump spot is symmetrical on the radiation entrance surface of the surface emitting semiconductor laser.

In accordance with at least one embodiment of the semiconductor laser module, the first cylindrical lens is the Facing pumping device and the second cylindrical lens faces away from the pumping device. That is, the first cylindrical lens, which extends in the direction parallel to the mounting surface, facing the pumping device. This cylindrical lens ensures fast axis collimation. The second cylindrical lens is then turned away from the pumping device and provides for slow axis collimation.

In accordance with at least one embodiment of the semiconductor laser module, the pump radiation extends in one

Distance of at least 600 microns above the mounting surface. For example, the pump radiation is at a distance of at least 750 micrometers above the mounting surface. That is, the area of the pump beam that has the greatest intensity is at a distance of at least 600 microns above the mounting surface. This can be achieved, for example, by virtue of the fact that the pump device has a pump beam source-for example an edge-emitting semiconductor laser-which is fastened on a mounting block which provides the necessary distance between the mounting surface of the module carrier and the pump beam source. That is, the mounting block is disposed between the mounting surface and the pump beam source.

In accordance with at least one embodiment of the semiconductor laser module, the mounting surface of the module carrier has a surface area of at most 100 square millimeters. For example, the module carrier is a cuboid module carrier. The

Mounting surface is then formed by the top surface at the top of the cuboid. The mounting surface has an area of at most 100 square millimeters, preferably at most 85 square millimeters, more preferably at most 70 square millimeters.

In accordance with at least one embodiment of the semiconductor laser module, the semiconductor laser module has a

Height of at most 3.5 millimeters, preferably at most three millimeters. The height of the semiconductor laser module is to be understood as the maximum extent of the semiconductor laser module in a direction which runs perpendicular to the mounting surface. That is, the distance from the lowest point of the semiconductor laser module to the highest point of the semiconductor laser module is preferably at most 3.5 millimeters, more preferably at most three millimeters. In this case, the lowest point of the semiconductor laser module is formed by the side facing away from the mounting surface of the module carrier. The highest point of the semiconductor laser module is given for example by a point which is arranged on that component of the semiconductor laser module which projects beyond the module carrier at the highest.

Overall, the semiconductor laser module is a particularly compact module that includes few components. The fact that only a few components are necessary to form the semiconductor laser module makes this possible

Accommodate these components on a very small mounting surface. Furthermore, with the number of components also reduces the effort for an adjustment of the components to each other. This allows a particularly simple and thus cost-effective production of the semiconductor laser module. In the following, the semiconductor laser module described here will be explained in more detail by means of exemplary embodiments and the associated figures.

Show it:

Figures IA and IB is a schematic side view and a schematic plan view of an embodiment of a semiconductor laser module described herein.

FIG. 2 shows a schematic perspective view of an optical element as can be used in the beam path of the pump radiation of a semiconductor laser module described here.

FIGS. 3A, 3B show schematic views of an optical element as can be used in the beam path of the pump radiation of a semiconductor laser module described here.

The same, similar or equivalent elements are provided in the figures with the same reference numerals. The figures and the proportions of the elements shown in the figures with each other are not to be considered to scale. Rather, individual elements can do better

Representability and / or exaggerated for better understanding.

FIG. 1A shows a schematic side view of an exemplary embodiment of one described here

Semiconductor laser module. FIG. 1B shows the associated schematic plan view. The semiconductor laser module comprises a module carrier 10. The module carrier 10 is for example, a board made of Direct Bonded Copper (DBC). Furthermore, it is possible for the module carrier to comprise a base body made of a ceramic material, such as aluminum nitride, which has metallizations on the top and bottom, which consist for example of copper or gold and has a thickness between 0.1 millimeter and 0.3 millimeter, preferably 0, 2 millimeters.

The module carrier 10 has a mounting surface 11, which is formed on the upper side of the module carrier 10. The

Base surface of the mounting surface 11 and thus the base of the module carrier 10 are preferably at most 100 square millimeters, more preferably at most 70 square millimeters. For example, the mounting surface has a length of eleven millimeters and a width of six millimeters.

On the mounting surface 11, the components of the semiconductor laser module are applied. On the mounting surface 11, for example, a pumping device 1 is applied. The pumping device 1 comprises a pumping source Ia and a mounting block Ib for the pumping source. The pump source Ia is mounted on the mounting surface 11 facing away from the mounting block Ib. The mounting block Ib is applied with its pump source Ia side facing away from the mounting surface 11, for example, soldered or glued. The pump source Ia produces highly divergent pump light. The pump source Ia is, for example, an edge-emitting semiconductor laser such as a wide-band laser having at least one emitter region. Pump radiation Ic generated by the pump source Ia during operation is transmitted through the single optical element 2 in the beam path of the pump radiation Ic between the pump device 1 and the pump focused surface emitting semiconductor laser 40. The optical element 2 is explained in more detail in connection with FIGS. 2, 3A and 3B.

The pump radiation Ic is focused on a radiation entrance surface of the semiconductor laser chip 4, for example at a 45 degree angle. The semiconductor laser chip 4 is part of the semiconductor laser 40. The semiconductor laser 40 comprises a mounting block 3, which is fastened with its mounting surface on the mounting surface 11 of the module carrier 10, for example, soldered or glued. The semiconductor laser chip 4 is applied to a heat sink 43 which is mounted on an upper surface of the mounting block 3. The heat sink 43 is optional. That is, the semiconductor laser chip 4 can also be applied directly to the mounting block 3 and fixed there. The semiconductor laser chip 4 is mounted on the mounting block 3 and the heat sink 43 by gluing, soldering or bonding.

The pumping radiation Ic is focused on the semiconductor laser chip 4 by the optical element 2 in such a way that a symmetrical pumping mote having a radius between approximately 25 micrometers and at most 60 micrometers is generated there. The semiconductor laser chip 4 is a surface emitting semiconductor laser chip (VECSEL) which is optically pumped by the pumping source 1a. During operation of the semiconductor laser chip 4, the heat flow through the mounting block 3 takes place through a 90 degree angle to the module carrier 20.

The semiconductor laser module further comprises a resonator, which is defined by a Bragg mirror, not shown, of the semiconductor laser chip 4 and the end mirror 7. The reflective surface of the end mirror 7 in this case comprises a coating which is highly reflective for the electromagnetic radiation of the fundamental wavelength generated by the semiconductor laser chip and a coating which is highly reflective, for those of the

Frequency conversion device 6 wavelength-converted electromagnetic radiation. The semiconductor laser chip 4 generates, for example, electromagnetic radiation in the spectral range for infrared radiation, which from the frequency conversion device 6 to electromagnetic

Radiation in the spectral range of green light is converted. For example, the pump light Ic has a wavelength of 808 nanometers, the semiconductor laser chip 4 generates radiation of wavelength 1060 nanometers and the frequency conversion device generates radiation of wavelength 530 nanometers.

The semiconductor laser module has a height H of at most 3.5 millimeters, preferably at most three millimeters, particularly preferably at most 2.5 millimeters. The height H is the distance from the underside of the module carrier 20 facing away from the mounting surface 11 to the highest point of the semiconductor laser module, which is formed, for example, by a component of the semiconductor laser module such as the semiconductor laser 40.

The resonator preferably has a length of at most ten millimeters. The frequency-converted radiation 8 is coupled out of the semiconductor laser module by an output coupler 5. The output coupler 5 can at the same time a

Folding mirror for polarization selection. For this purpose, the output coupler 5 has, for example, a coating which is suitable for electromagnetic radiation of the fundamental wavelength is highly reflective. In addition, the output coupler 5 has a coating which is designed to be antireflective for frequency-converted radiation. In this way, the electromagnetic radiation of the fundamental wavelength is held in the resonator, whereas frequency-converted radiation 8 can leave the semiconductor laser module through the output coupler 5.

The output coupler 5 is in the present embodiment as a plane mirror for the electromagnetic radiation of

Fundamental wavelength executed. The highly reflective for the radiation of the fundamental frequency formed coating of the Auskopplers 5 can be designed polarisationsfestlegend. As a result, the output coupler 5 also serves to polarize the radiation circulating in the resonator. Optionally, the output coupler 5 can be arranged in the Brewster angle, which likewise defines the polarization of the circulating laser radiation.

FIG. 2 shows a schematic perspective illustration of an optical element 2, as used in an embodiment of the semiconductor laser module described here. The optical element 2 are crossed cylindrical lenses. That is, the optical element 2 has a first cylindrical lens 201 and a second cylindrical lens 202. The first cylindrical lens 201 is located on a first radiation passage area 23 of the optical element. It extends in the direction 21. The direction 21 extends parallel to the mounting surface 11 of the semiconductor laser module. That is, the optical

Element 2 is attached with its underside 2a on the mounting surface 11 of the module carrier 10, for example glued. The second cylindrical lens 202 is located on the second radiation passage area 24. It runs in the direction 22, which is perpendicular to the mounting surface 11 of the module carrier 10. The optical element 2 is arranged in the beam path of the pumping radiation Ic in such a way that the first cylindrical lens 201 faces the pumping device 1, so that the pumping radiation Ic first enters the first radiation passage area 23 when entering the optical element 2. The pump radiation Ic then leaves in focus the optical element 2 at the second radiation passage area 24, compare FIG. 3A.

FIG. 3A shows a schematic top view of the optical element 2. FIG. 3B shows a schematic side view of the side surface 2b of the optical element 2.

The optical element is arranged such that the pump radiation to the directions 21, 22 is perpendicular or substantially perpendicular. The

Radiation passage surfaces 23, 24 each have an interface with the surrounding space, that is, toward the air. The optical element is formed, for example, from a material having a refractive index of at least 1.8 at the wavelength of the pump radiation Ic. It serves for

Collimation of the slow and fast axis direction.

For example, the company LIMO-Lissotschenko Mikrooptik GmbH offers such a lens as a fiber coupler 9003.002. In contrast to the intended use as a fiber coupler is the

Lens present as the only optical element in the beam path of the pump radiation Ic operated. The lens is not optically connected to a diode and / or a fiber optic means connected to optical adhesive or the like, but the radiation passage areas 23, 24 of the optical element each have an interface to the air out.

The invention is not limited by the description based on the embodiments of these. Rather, the invention encompasses every new feature as well as every combination of features, which in particular includes any combination of features in the patent claims, even if this feature or combination itself is not explicitly described in the claims

Claims or embodiments is given.

This patent application claims the priority of German Patent Application 102008030254.6, the disclosure of which is hereby incorporated by reference.

Claims

claims

1. semiconductor laser module comprising - a module carrier (10) with a mounting surface (11),

a pumping device (1) arranged on the mounting surface (11),

a surface emitting semiconductor laser (40) disposed on the mounting surface (11), and a frequency conversion device (6) disposed on the mounting surface (11), wherein

- In the beam path of the pumping beam (Ic) between the pumping device and surface emitting semiconductor laser (40) is exactly one optical element (2), and wherein - radiant passage surfaces (23,24) of the optical element bordering on air.

2. The semiconductor laser module according to the preceding claim, wherein the optical element (2) comprises two crossed cylindrical lenses (201,202), wherein the optical element (2) is integrally formed.

3. The semiconductor laser module according to the preceding claim, wherein a first cylindrical lens (201) extends parallel to the mounting surface and in which a second

Cylindrical lens (202) extends perpendicular to the mounting surface.

4. The semiconductor laser module according to the preceding claim, wherein the first cylindrical lens (201) facing the pumping device and the second cylindrical lens (202) facing away from the pumping device.

5. Semiconductor laser module according to one of the preceding claims, in which the pump beam (Ic) extends at a distance (D) of at least 600 μm above the mounting surface.

6. The semiconductor laser module according to the preceding claim, wherein the pumping device (1) comprises a pump beam source (Ia) and a mounting block (Ib) for the pump beam source, wherein the mounting bracket (Ib) between the mounting surface and the pump beam source is arranged.

7. The semiconductor laser module according to one of the preceding claims, wherein the mounting surface (11) of the module carrier (10) has a surface area of at most 100 mm2.

8. The semiconductor laser module according to one of the preceding claims, wherein the height (H) of the semiconductor laser module is at most 3 mm.