JPH07131112A - Laser diode module - Google Patents

Abstract

PURPOSE:To provide a laser diode module, which is formed by welding a chip carrier to a lens holder by YAG laser, allows minimum behavior change to the environmental temperature change, constitutes an optical isolator at a low cost and allows no reduction of the optical output even when the laser diode module is fixed to a heat sink, etc., by excessive force. CONSTITUTION:A kovar chip carrier protruding part 3b that can be welded by YAG welding is bonded to a copper-tungsten alloy chip carrier 3a by silver soldering, and a first lens holder 5 is fixed to the chip carrier protruding part 3b by YAG laser welding. An analyzer 13 is laminated to a Faraday rotator 10 by optically transparent adhesive, and is laminated to optical fiber 18 and a glass pipe 24 by optically transparent adhesive.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser diode module used as a light source for optical fiber communication, for example.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view showing a conventional laser diode module, in which 1 is 1.3 μm.
Laser diode oscillating at a wavelength of 2 is a submount soldered to the laser diode 1, 3 is a chip carrier fixed to the submount 2 by soldering, and 4 is a first carrier placed in front of the laser diode. A lens 5 is a first lens holder that holds the first lens 4 and is soldered to the chip carrier 3, and 6 is a laser diode 1.
Etc., 7 is a glass window for hermetically sealing the package 6, 8 is a Peltier element sandwiched between the chip carrier 3 and the package 6, and 9 is made of polarized glass placed on the emission optical path of the laser diode 1. 10 is a Faraday rotator placed on the exit optical path of the laser diode 1 and behind the polarizer 9, and 11 is a Faraday rotator 1.
A cylindrical magnet arranged to surround 0, 1
2 is a polarizer 9 and a Faraday rotator 10 is a magnet 1
A polarizer holder fixed to 1 is provided, 13 is an analyzer made of polarized glass placed behind the Faraday rotator 10 on the emission optical path of the laser diode 1, and 14 fixes the analyzer 13 to the magnet 11. An analyzer holder, 15 is a magnet holder for fixing the magnet 11 to the package 6 by YAG welding, 16 is a second lens placed behind the analyzer 13 on the emission optical path of the laser diode 1, and 17 is a magnet for the second lens 16. A second lens holder fixed by YAG welding to the holder 15, and 18 is an optical fiber of a single transverse mode placed at a position where the emitted light from the laser diode 1 is focused,
Reference numeral 19 is a nylon fiber jacket for reinforcing the optical fiber 18, 20 is a ferrule made of stainless steel for fixing the optical fiber 18 and the fiber jacket 19, 21 is a ferrule holder for fixing the ferrule 20 to the second lens holder 17, 22 and 23 is package 6
For fixing the heat sink to a heat sink (not shown)
And a second screw.

Next, the operation will be described. The laser light emitted from the laser diode 1 is converted into parallel light by the first lens 4 and transmitted through the glass window 7, the polarizer 9, the Faraday rotator 10 and the analyzer 13, and then the second lens 1
It is condensed again by 6 and becomes the propagation mode of the optical fiber 18.

As a further function, the polarizer 9, the Faraday rotator 10 which has a polarization rotation function of 45 degrees by the magnet 11, and the analyzer 13 constitute an optical isolator, and are separated from the optical fiber 18. The light that has entered the Faraday rotator 10 passes through the analyzer 13
As a result of the polarization rotation of 5 degrees, it is blocked by the polarizer 9.

As a result of considering the heat radiation of the laser diode, the chip carrier 3 is required to be a material having a thermal conductivity of 200 W / (m · K) or more, and a copper tungsten alloy is used. FIG. 3 illustrates the relationship between the thermal conductivity of the material and the temperature rise of the laser diode. Fig. 5 shows 200W to suppress the temperature rise of the laser diode to less than 1 degree.
It indicates that it is necessary to select a material of / (m · K) or more.

A flange is formed on the package 6 by cutting, and the package 6 can be fixed by a first screw 22 and a second screw 23 by a heat sink (not shown).

[0007]

Although the conventional laser diode module is constructed as described above, since the copper-tungsten alloy having good thermal conductivity is used as the chip carrier, the heat dissipation is too good. There is a problem that YAG laser welding cannot be performed.

An optical isolator is inserted between the first lens 4 and the second lens 16 and has the thickest beam diameter. Therefore, the polarizer 9, the Faderer rotator 10,
There is a problem that the analyzer 13 becomes large and expensive.

Further, since a part of the package 6 is processed into a flange shape so that it can be screwed, when the screws are tightened with an excessive torque or the package 6 is mounted on a heat sink with poor flatness, There is a problem that the package is distorted and the amount of incidence on the optical fiber 18 is reduced.

The present invention has been made to solve the above problems, and an object thereof is to construct a laser diode module having a YAG laser weldable chip carrier.

It is another object of the present invention to construct a laser diode module having a chip carrier that minimizes a change in behavior with respect to a change in ambient temperature.

Another object is to obtain an inexpensive laser diode module.

Further, it is an object of the present invention to obtain a laser diode module which does not reduce the optical output even when it is attached to a heat sink or the like with an excessive force.

[0014]

The laser diode module according to the present invention has a chip carrier of 200 W.
A metal of / (m · K) or more and a metal of 200 W / (m · K) or less are joined by brazing. Further, the laser diode module according to the present invention uses a chip carrier in which a metal of 200 W / (m · K) or more and a metal of 200 W / (m · K) or less are joined by press fitting. Further, in the laser diode module according to the present invention, the metal part having a thermal conductivity of 200 W / (m · K) or less of the chip carrier is positioned substantially rotationally symmetrical with respect to the optical axis of the laser diode. . Further, in the laser diode module according to the present invention, an analyzer which is a component of the optical isolator is adhesively fixed to the optical fiber with a transparent adhesive. Further, the laser diode module according to the present invention has a resin flange attached to the package.

[0015]

In the laser diode module according to the present invention, the first lens can be YAG laser welded by having the portion having a low chip carrier thermal conductivity.
Further, in the laser diode module according to the present invention, the YAG laser welding portion is distributed symmetrically with respect to the optical axis of the laser, so that the change in behavior with respect to the change in environmental temperature is minimized. Further, in the laser diode module according to the present invention, the analyzer is adhered and fixed to the optical fiber with a transparent adhesive, so that the effective diameter of the optical isolator can be reduced and the cost is reduced. Further, the laser diode module according to the present invention has a resin flange attached to the package to obtain a laser diode module which does not cause a decrease in optical output even when it is attached to a heat sink or the like by excessive force.

[0016]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a laser diode that oscillates at a wavelength of 1.3 μm, and 2 is a laser diode 1.
The submount 3a soldered to the chip mount 3a is a chip carrier made of a copper-tungsten alloy fixed to the submount 2 by soldering, and 3b has a melting point of about 900 on the chip carrier 3a.
Chip carrier protrusions made of Kovar fixed by silver brazing at 4 degrees, 4 is a first lens placed on the front surface of the laser diode, 5 is a first lens 4 and is soldered to the chip carrier 3. First lens holder, 6
Is a package that surrounds the laser diode 1 and the like, 7 is a glass window that hermetically seals the package 6, and 8 is a chip carrier 3
Peltier element sandwiched between the package and the package 6, 16
Is a second lens placed on the emission optical path of the laser diode 1, 17 is a second lens holder for fixing the second lens 16 to the package 6, and 9 is the laser diode 1
On the exit optical path of the laser diode made of polarizing glass, 10 is a Faraday rotator placed on the exit optical path of the laser diode 1 and behind the polarizer 9, and 13 is a laser diode. An analyzer made of polarized glass placed behind the Faraday rotator 10 on the output optical path of 1.
Reference numeral 11 is a cylindrical magnet arranged so as to surround the Faraday rotator 10, 12a is a polarizer holder for fixing the polarizer 9 to the magnet 11, and 18 is placed at a position where light emitted from the laser diode 1 is condensed. A single mode optical fiber, 19 is a nylon fiber jacket for reinforcing the optical fiber 18, 20 is a stainless steel ferrule for fixing the fiber jacket 19, 2
4 is a glass pipe adhered to the outer circumference of the optical fiber 18,
Reference numeral 21 is a ferrule holder that fixes the ferrule 20 to the second lens holder 17, 25 is a plastic flange that is adhesively fixed to the package 6, and 22 and 23 are first and second fixing flanges 25 to a heat sink (not shown). The second screw. Faraday rotator 9,
The analyzer 13, the optical fiber 18, and the glass pipe 24 are bonded and fixed with an optically transparent adhesive at a wavelength of 1.3 μm.

Next, the operation will be described. The laser light emitted from the laser diode 1 is converted into parallel light by the first lens 4, transmitted through the glass window 7, and then collected again by the second lens 16, and the polarizer 9, the Faraday rotator 10, The light is transmitted through the analyzer 13 and enters the propagation mode of the optical fiber 18.

As a further function, the polarizer 9, the Faraday rotator 10 provided with the polarization rotation function of 45 degrees by the magnet 11, and the analyzer 13 constitute an optical isolator, and are separated from the optical fiber 18. The light that has entered the Faraday rotator 10 passes through the analyzer 13
As a result of the polarization rotation of 5 degrees, it is blocked by the polarizer 9.

As a result of considering the heat radiation of the laser diode, the chip carrier 3a has a thermal conductivity of 200 W / (m · K).
The above materials are required and the thermal conductivity is about 400W /
A copper-tungsten alloy of (m · K) is used. The material having a thermal conductivity of 200 W / (m · K) or more includes, for example, copper, gold, silver and aluminum. The above operation is exactly the same as that of the conventional embodiment shown in FIG.

Next, the characteristic operation realized by the present invention will be described. The chip carrier 3a has a thermal conductivity of about 8
The Kovar-made chip carrier protrusion 3b capable of YAG welding at 0 W / (m · K) is provided by silver brazing, and the gap between the first lens holder and the chip carrier protrusion 3b is fixed by YAG laser welding. ing. Also, the material of the chip carrier protrusion 3b (heat conductivity 200 W / m.
Examples of materials (K or less) include Kovar, iron, stainless steel, and platinum.

FIG. 2 is a perspective view showing how the chip carrier 3a and the chip carrier protrusion 3b are joined. Two protrusions are installed at positions substantially symmetrical with respect to the laser diode 1. Therefore, even if the temperature of the laser diode 1, the chip carrier 3a, the chip carrier 3b, the first lens 4, and the first lens holder 5 are simultaneously changed, the misalignment in the direction perpendicular to the optical axis of the laser diode is caused. Is not generated, it is possible to minimize the change in behavior with respect to the change in environmental temperature.

Further, the analyzer 13 is the Faraday rotator 1
0 is adhered to the optical fiber 18 and the glass pipe 24 with an optically transparent adhesive and then is adhered to the optical fiber 18 and the glass pipe 24 with an optically transparent adhesive. The analyzer 13 and the Faraday rotator 10 are limited to a certain degree.
The required effective diameter can also be minimized. In general, the cost of the analyzer and the Faraday rotator is largely determined by the required effective diameter, so the cost of the laser diode module is also reduced.

Further, a plastic flange 25 is fixedly adhered to the package 6, and the module is attached to an external component such as a heat sink by the first and second screws 22 and 23 via the flange. Therefore, even if the screw tightening torque is excessive, the flexible plastic material absorbs mechanical strain and the delicate optical coupling system can be stably maintained.

Example 2. In the first embodiment, the chip carrier protrusion 3b fixed by silver brazing is shown, but the same effect as the above embodiment can be obtained by press fitting. FIG. 3 shows a chip carrier 3 joined by press fitting.
It is a perspective view which shows the state of a and the chip carrier protrusion part 3c.

[0025]

As described above, according to the present invention, the chip carrier partially has a portion having a thermal conductivity of 200 W / (m · K) or less, so that the first lens is made to be YAG.
Laser welding is now possible, which has the effect of maintaining high reliability against external environmental conditions.

Further, according to the present invention, since the chip carrier projections are arranged symmetrically with respect to the optical axis of the laser diode 1, the YAs of the chip carrier and the first lens holder are arranged.
There is an effect that the symmetry with respect to the optical axis of the laser is maintained in the joint portion by the G laser welding, and the change in behavior with respect to the change in environmental temperature can be minimized.

Further, according to the present invention, the effective diameter of the optical isolator can be reduced by adhering and fixing the analyzer to the optical fiber with a transparent adhesive, and the reflection at the end face of the optical fiber, which has been difficult in the past, can be achieved. The effect is that elimination of losses can be achieved.

Further, according to the present invention, by attaching a plastic flange to the package, it is possible to obtain a laser diode module which does not cause a decrease in light output even when it is attached to a heat sink or the like with an excessive force, and it is possible to obtain a conventional laser diode module. Therefore, there is an effect that it is possible to eliminate the formation of the flange shape due to the cutting process on the package, which has been a factor of cost increase.

[Brief description of drawings]

FIG. 1 is a sectional view showing a laser diode module according to an embodiment of the present invention.

FIG. 2 is a perspective sectional view showing a chip carrier of a laser diode module according to an embodiment of the present invention.

FIG. 3 is a perspective view showing a chip carrier of a laser diode module according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a conventional laser diode module.

FIG. 5 is a diagram showing the relationship between the thermal conductivity of the chip carrier and the temperature rise of the laser diode.

[Explanation of symbols]

 1 Laser Diode 2 Submount 3a Chip Carrier 3b Chip Carrier Protrusion 4 First Lens 5 First Lens Holder 6 Package 7 Glass Window 9 Polarizer 10 Faraday Rotor 11 Magnet 13 Analyzer 16 Second Lens 17 Second Lens holder 18 Optical fiber 25 Flange

Claims (5)

[Claims] 1. A laser diode, a chip carrier for holding the laser diode, a lens attached to the chip carrier, a lens holder for holding the lens, a package for hermetically sealing the laser diode, and In a laser diode module including an optical fiber attached to a package, the lens, and an optical isolator inserted between the optical fibers, the chip carrier has a thermal conductivity of 200 W / (m.
A laser diode module characterized in that a chip carrier and a lens holder are joined by YAG laser welding, using a combination of a metal of K) or more and a metal of 200 W / (m · K) or less. 2. The chip carrier has a thermal conductivity of 200.
2. The laser diode module according to claim 1, wherein the metal portion of W / (m · K) or less is located substantially rotationally symmetrical with respect to the optical axis of the laser diode. 3. A laser diode, a chip carrier for holding the laser diode, a lens attached to the chip carrier, a package hermetically sealing the laser diode, and an optical fiber attached to the package. In the laser diode module including the lens and the optical isolator inserted between the optical fibers, the analyzer which is a component constituting the isolator is adhesively fixed to the optical fiber with a transparent adhesive. Laser diode module. 4. A laser diode, a chip carrier for holding the laser diode, a lens attached to the chip carrier, a package for hermetically sealing the laser diode, and an optical fiber attached to the package. A laser diode module comprising a resin flange attached to the package and an optical isolator inserted between the lens and the optical fiber. 5. A chip carrier having a thermal conductivity of 200.
5. A laser diode according to claim 1, wherein a metal having a W / (m · K) or more and a metal having a W / (m · K) or less is combined by brazing or press fitting. module.