JPH11271573A - Semiconductor laser device and its assembling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a semiconductor laser device which is small in size and high in coupling efficiency. SOLUTION: This semiconductor laser device is constituted by mounting a semiconductor laser element 17 in which a spot size converter 15 for expanding spot size is integrated on a chip carried 12, and the spot size of laser light 18 emitted by the semiconductor laser element 17 with the converter is expanded to decrease the divergence angle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a semiconductor laser device used as a light source for optical fiber communication and the like, and a method of assembling the same.

[0002]

2. Description of the Related Art FIG.
FIG. 1 is a cross-sectional view of a conventional semiconductor laser device disclosed in Japanese Unexamined Patent Application Publication No. H10-115,004. In the figure, a chip carrier 2 is fixed in a package 1. A semiconductor laser element 3 that emits laser light is mounted on the chip carrier 2. The semiconductor laser element 3 is provided with an optical waveguide 4 for guiding the generated laser light. A lens 6 for condensing laser light 5 emitted from the semiconductor laser element 3 is provided in the package 1.
Has been fixed.

A ferrule 8 for holding an input end of an optical fiber 7 is fixed to an end of the package 1 via a holder 9. At the input end of the optical fiber 7, a converter 7a having a core diameter enlarged in a tapered shape is provided.

Next, the operation will be described. The laser beam 5 emitted from the optical waveguide 4 of the semiconductor laser device 3 is condensed by a lens 6 and enters a conversion section 7a of an optical fiber 7. The spot size of the laser beam 5 incident on the conversion unit 7a is gradually reduced, converted into the spot size of the optical fiber 7, and guided to a transmission line optical fiber (not shown) of the optical communication system.

[0005]

In the conventional semiconductor laser device configured as described above, since the spot size of the laser beam 5 emitted from the semiconductor laser element 3 is small, the spread angle of the laser beam 5 is large. , Optical fiber 7
In order to increase the coupling efficiency, the lens 6 having a large aperture diameter must be used, and there is a problem that the entire device becomes large. Further, since a change in the optical output with respect to a change in the relative position between the semiconductor laser element 3 or the chip carrier 2 and the lens 6 is large, an error in the bonding position between the semiconductor laser element 3 and the chip carrier 2 and the bonding between the chip carrier 2 and the package 1 There is also a problem that the light output greatly changes due to a position error, a deformation of the package 1 itself due to thermal and temporal factors, and the like.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is possible to improve the coupling efficiency without increasing the overall size and to stabilize the optical output. And a method of assembling the same.

[0007]

According to a first aspect of the present invention, there is provided a semiconductor laser device for emitting a laser beam, and a spot size converter for enlarging a spot size of the laser beam emitted from the semiconductor laser device. And a lens for condensing the laser light passing through the spot size converter, and an optical fiber into which the laser light condensed by the lens is incident.

According to a second aspect of the present invention, a semiconductor laser device and a spot size converter are integrated to constitute a semiconductor laser device with a converter.

According to a third aspect of the present invention, there is provided an optical fiber chip wherein an input end is opposed to a semiconductor laser element, and a converter for expanding a spot size of laser light is provided at an output end. Is used as a spot size converter.

According to a fourth aspect of the present invention, a conversion section is formed by enlarging a core diameter by thermal diffusion.

According to a fifth aspect of the present invention, there is provided a semiconductor laser device in which a lens portion is provided on an input side end face of an optical fiber chip.

According to a sixth aspect of the present invention, there is provided a semiconductor laser device having an antireflection film provided on an output end face of an optical fiber chip.

According to a seventh aspect of the present invention, in the semiconductor laser device, an output end face of the optical fiber chip is inclined with respect to a plane perpendicular to the axis of the optical fiber chip.

The semiconductor laser device according to the invention of claim 8 uses an optical fiber chip having a sectional shape in which the center of the core is eccentric.

A semiconductor laser device according to a ninth aspect of the present invention uses an optical fiber chip having a chip main body having a circular cross section and a projecting portion attached to a part of an outer peripheral surface of the chip main body in a circumferential direction. Things.

According to a tenth aspect of the present invention, there is provided a semiconductor laser device using an optical fiber chip having a cross-sectional shape in which a part of a circular cross-section in a circumferential direction is removed.

According to an eleventh aspect of the present invention, there is provided a method of assembling a semiconductor laser device, comprising: an optical fiber chip having a conversion portion for enlarging a spot size of laser light provided at an output end; Fixing the optical fiber chip to the chip carrier at a position axially spaced from the input side end face so as to face the element, detecting the output of the laser light emitted from the semiconductor laser element and passing through the optical fiber chip, Deforming the input side end and displacing the input side end face, and heating and partially melting the input side end and then cooling to fix the position of the input side end face. Including.

According to a twelfth aspect of the present invention, in the method of assembling a semiconductor laser device, the optical fiber is mounted on the chip carrier at a position axially spaced from the input end face so that the input end face faces the semiconductor laser element. Fixing the optical fiber, detecting the output of the laser light emitted from the semiconductor laser element and passing through the optical fiber, deforming the input end of the optical fiber to displace the input end, and After the portion is heated and partially melted, the portion is cooled to fix the position of the input-side end face.

In the method for assembling a semiconductor laser device according to a thirteenth aspect, the input side end is heated by using a carbon dioxide gas laser.

According to a fourteenth aspect of the present invention, the input side end is heated by using an electrode discharge.

According to a fifteenth aspect of the present invention, in the method of assembling a semiconductor laser device, the input side end is heated using a micro burner.

According to a sixteenth aspect of the present invention, in the method of assembling a semiconductor laser device, a converter for enlarging a spot size of a laser beam is provided at an output end and has a cross-sectional shape in which a core center is eccentric. Fiber optic chip
A step of arranging the optical fiber chip in a V-shaped groove so that its input side end face faces the semiconductor laser element, while detecting the output of laser light emitted from the semiconductor laser element and passing through the optical fiber chip; The method includes a step of rotating the optical fiber chip in the groove and a step of fixing the optical fiber chip in the groove with the rotation of the optical fiber chip restricted.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a sectional view of a semiconductor laser device according to Embodiment 1 of the present invention. In the figure, a chip carrier 12 is fixed in a package 11.
A semiconductor laser element 13 that generates a laser beam is mounted on the chip carrier 12. Semiconductor laser device 13
Is provided with an optical waveguide 14 for guiding the generated laser light.

The chip carrier 12 is provided with a spot size converter 15 for enlarging the light emitting spot size of the guided light led out of the optical waveguide 14 of the semiconductor laser 13. The spot size converter 15 has an optical waveguide 16 having a tapered cross section. The semiconductor laser device 13 and the spot size converter 15 are integrated to form a semiconductor laser device 17 with a converter.

In the package 1, a lens 19 for collecting a laser beam 18 emitted from a semiconductor laser device 17 with a converter is fixed. A ferrule 8 for holding the input end of the optical fiber 7 is provided at the end of the package 11.
Are fixed via a holder 9. At the input end of the optical fiber 7, a converter 7a having a tapered core diameter is provided.
Is provided.

Next, the operation will be described. The light generated by the semiconductor laser device 13 propagates through the optical waveguide 14, enters the optical waveguide 16 of the spot size converter 15, has its spot size enlarged, and is emitted from the semiconductor laser device 17 with a converter. The emitted laser light 18 is
The light is condensed by the lens 19 and is converted by the conversion unit 7a of the optical fiber 7.
Incident on. The spot size of the laser beam 18 incident on the conversion unit 7a is gradually reduced, converted into the spot size of the optical fiber 7, and guided to a transmission line optical fiber (not shown) of the optical communication system.

In such a semiconductor laser device, since the spot size of the laser beam 18 emitted from the semiconductor laser device 17 with a converter is enlarged by the spot size converter 15, the spread angle of the laser beam 18 is It becomes smaller than the spread angle when only the semiconductor laser element 13 is used. For this reason, the aperture diameter of the lens used can be reduced, and the entire apparatus can be reduced (thinned).

Further, since the spot size of the laser beam 18 emitted from the semiconductor laser device 17 with the converter is enlarged, the light with respect to the relative position change between the semiconductor laser device 17 with the converter and the chip carrier 12 and the lens 19 is increased. Output change can be reduced, and reliability can be improved.

Further, a conversion section 7a is provided at the input end of the optical fiber 7, and the core size of the input end face is enlarged. Can be reduced, and a change in the optical output with respect to a change in the relative position between the ferrule 8 and the holder 9 and the lens 19 can be reduced. Therefore, the coupling efficiency can be improved, and the reliability can be improved. .

The conversion section 7a of the optical fiber 7 can be easily formed by enlarging the cross section of the input end of the core of the optical fiber 7 by thermal diffusion.

Embodiment 2 Next, FIG. 2 is a sectional view of a main part of a semiconductor laser device according to a second embodiment of the present invention. In the figure, a semiconductor laser element 13 and a chip carrier 21 fixed in a package 11 (FIG. 1) are provided.
An optical fiber chip 22 as a spot size converter is mounted. The input side end face of the optical fiber chip 22 has a lens portion 22 a facing the semiconductor laser device 13.
Is provided. At the output end of the optical fiber chip 22, there is provided a conversion section 22b whose core (optical waveguide) section is tapered to increase the spot size. Further, an antireflection film 23 is provided on the output end face of the optical fiber chip 22.

Next, the operation will be described. The laser light emitted from the semiconductor laser element 13 is transmitted to the lens portion 22a.
Thus, the optical fiber is coupled to the optical waveguide of the optical fiber chip 22 with higher efficiency. The laser beam that has entered the optical fiber chip 22 has its spot size enlarged by the converter 22b, and is emitted from the output-side end surface that is an open end. The laser light emitted from the optical fiber chip 22 enters the optical fiber 7 via the lens 19 as in FIG. 1, and is guided to the transmission line optical fiber of the optical communication system.

In such a semiconductor laser device, since the spot size of the laser light emitted from the semiconductor laser element 13 is enlarged by the converter 22b of the optical fiber chip 22, the spread angle of the light emitted from the optical fiber chip 22 is increased. Becomes smaller. For this reason, the aperture diameter of the lens used can be reduced, and the entire apparatus can be reduced (thinned).

Since the spot size of the light emitted from the optical fiber chip 22 is enlarged, the change in the optical output with respect to the change in the relative position between the optical fiber chip 22 and the lens 19 can be reduced, and the reliability is improved. Can be improved.

Further, since the lens section 22a is provided on the input end face of the optical fiber chip 22, the semiconductor laser element 1
The coupling efficiency of laser light between the optical fiber chip 3 and the optical fiber chip 22 can be improved. Also, the optical fiber chip 2
Since the anti-reflection film 23 is provided on the output side end face of No. 2, the reflected return light from the output side end face can be reduced, and the noise and the high stability of the entire device can be achieved.

Embodiment 3 Next, FIG. 3 is a sectional view of a main part of a semiconductor laser device according to a third embodiment of the present invention. In the figure, an optical fiber chip 24 as a spot size converter facing a semiconductor laser element 13 is fixed to a chip carrier 21. The optical fiber chip 24 has a spot size of the semiconductor laser device 13.
, And has a high relative refractive index difference. At the output end of the optical fiber chip 24, a converter 24a having a tapered core section is provided to increase the spot size. Also, the output side end face 24b of the optical fiber chip 24
Are inclined with respect to a plane perpendicular to the axis of the optical fiber chip 24.

Next, the operation will be described. The laser light emitted from the semiconductor laser device 13 is coupled to the optical waveguide of the optical fiber chip 24 with high efficiency. The laser beam that has entered the optical fiber chip 24 has its spot size enlarged by the conversion unit 24a, and is emitted from the inclined output side end face. The laser light emitted from the optical fiber chip 24 enters the optical fiber 7 via the lens 19 as in FIG. 1, and is guided to the transmission line optical fiber of the optical communication system.

In such a semiconductor laser device, since the spot size of the laser light emitted from the semiconductor laser element 13 is enlarged by the converter 24a of the optical fiber chip 24, the spread angle of the light emitted from the optical fiber chip 24 is increased. Becomes smaller. For this reason, the aperture diameter of the lens used can be reduced, and the entire apparatus can be reduced (thinned).

Further, since the spot size of the light emitted from the optical fiber chip 24 is enlarged, the change in the optical output with respect to the change in the relative position between the optical fiber chip 24 and the lens 19 can be reduced, and the reliability is improved. Can be improved.

Further, since the output side end face 24a of the optical fiber chip 24 is formed as an inclined surface, the amount of reflected light returning from the output side end face 24a can be reduced, and the noise and the stability of the entire device can be reduced. Can be.

In the first to third embodiments, since the semiconductor laser element 13 and the optical fiber 7 are separated by the lens 19 and the optical fiber chip 22, the optical fiber chip 22 and the lens 19 in the package 11 are separated. Window glass (not shown) between the lens 19 and the optical fiber 7
And the reliability of the semiconductor laser device 13 can be improved.

Embodiment 4 Next, FIG. 4 is a cross-sectional view showing a method of assembling a semiconductor laser device according to a fourth embodiment of the present invention, FIG. 5 is a cross-sectional view showing a state subsequent to FIG. 4, and FIG. It is sectional drawing. The configuration of the semiconductor laser device is the same as that of the second embodiment.

In the assembling method according to the fourth embodiment, first, the semiconductor laser device 13 and the optical fiber chip 22 are fixed to the chip carrier 21 as shown in FIG. At this time, the optical fiber chip 22 fixes only the output end to the chip carrier 21 with a predetermined accuracy while floating a predetermined length range from the lens portion 22a in the air. Next, while detecting the level of laser light emitted from the semiconductor laser element 13 and passing through the optical fiber chip 22, FIG.
Then, the input side end of the optical fiber chip 22 is pressed and curved in the direction of arrow A to displace (finely move) the lens portion 22a.

As described above, the lens portion 22a is displaced, and the level of the laser beam reaches a predetermined value.
When a reaches the optimum coupling position, the input side end of the optical fiber chip 22 is locally heated as shown by the arrow B in the figure, and the input side end is partially melted. Thereafter, by cooling the optical fiber chip 22, the lens portion 22a
Is fixed at the optimum coupling position as shown in FIG.

In such a method of assembling a semiconductor laser device, the optical fiber chip 22 is mounted on the chip carrier 21 without any adjustment with a predetermined accuracy, and then only the input end of the optical fiber chip 22 is deformed. Since the lens portion 22a can be fixed at the optimum coupling position, the coupling efficiency of the laser beam can be easily improved, and the assembly of the device can be facilitated. Further, there is no need to provide a structure for adjusting the relative positional relationship between the semiconductor laser element 13 and the optical fiber chip 22 in the chip carrier 21, and the configuration can be simplified.

As a means for locally heating and melting the input side end of the optical fiber chip 22, for example, a carbon dioxide gas laser, an electrode discharge, a micro burner, or the like can be used. Can be.

Embodiment 5 FIG. 7 is a sectional view showing a method of assembling a semiconductor laser device according to a fifth embodiment of the present invention.
FIG. 8 is a cross-sectional view showing a state of the latter part of FIG. 7, and FIG. 9 is a sectional view showing a state of the latter part of FIG.

In the method of assembling the semiconductor laser device according to the fifth embodiment, first, the semiconductor laser element 13 and the optical fiber 26 are fixed to the chip carrier 21 as shown in FIG. At this time, the optical fiber 26 is fixed to the chip carrier 21 at a position at a predetermined distance from the lens portion 26a located on the input side end face. As a result, the input end of the optical fiber 26 floats in the air. next,
While detecting the level of the laser light emitted from the semiconductor laser element 13 and passing through the optical fiber 26, the input side end of the optical fiber 26 is pressed and curved in the direction of arrow A in FIG.
The lens unit 26a is displaced (finely moved).

As described above, the lens portion 26a is displaced, and the level of the laser beam reaches a predetermined value.
When a reaches the optimum coupling position, the input end of the optical fiber 26 is locally heated as shown by the arrow B in the figure, and the input end is partially melted. Thereafter, by cooling the optical fiber 26, the lens portion 26a is fixed at the optimum coupling position as shown in FIG.

In such a method of assembling a semiconductor laser device, the optical fiber 26 is mounted on the chip carrier 21 without any adjustment with a predetermined accuracy, and then only the input end of the optical fiber 26 is deformed to form the lens portion. Since 26a can be fixed at the optimum coupling position, the coupling efficiency of the laser beam can be easily improved, and the assembly of the device can be facilitated.
Further, it is not necessary to provide a structure for adjusting the relative positional relationship between the semiconductor laser device 13 and the optical fiber 26 in the chip carrier 21, and the configuration can be simplified. Further, since the lens section 26a is provided on the input side end face of the optical fiber 26, the coupling efficiency can be further improved.

Embodiment 6 FIG. Next, FIG. 10 is a sectional view showing a method of assembling a semiconductor laser device according to a sixth embodiment of the present invention, FIG. 11 is a sectional view showing a state subsequent to FIG. 10, and FIG. It is sectional drawing.

In the method of assembling a semiconductor laser device according to the sixth embodiment, first, the semiconductor laser element 13 and the optical fiber 27 are fixed to the chip carrier 21 as shown in FIG. At this time, the optical fiber 27 fixes the position at a predetermined distance from the input side end face to the chip carrier 21. As a result, the input end of the optical fiber 27 floats in the air. The optical fiber 27 has a spot size close to that of the semiconductor laser element 13 and has a high relative refractive index difference, and is connected to a transmission line of an optical communication system. Thereafter, while detecting the level of the laser light emitted from the semiconductor laser element 13 and passing through the optical fiber 27, the input side end of the optical fiber 27 is pressed and curved in the direction of arrow A in FIG. Is displaced (finely moved).

As described above, when the input side end face is displaced and the laser beam level reaches a predetermined value and the input side end face reaches the optimum coupling position, the input side end of the optical fiber 27 is moved to the arrow B in the figure. As shown in (1), local heating is performed to partially melt the input side end. Thereafter, by cooling the optical fiber 27, the input side end face is fixed at the optimum coupling position as shown in FIG.

In such a method of assembling a semiconductor laser device, the optical fiber 27 is mounted on the chip carrier 21 with a predetermined accuracy without any adjustment, and then only the input end of the optical fiber 27 is deformed to change the input side. Since the end face can be fixed at the optimum coupling position, the coupling efficiency of the laser beam can be easily improved, and the assembly of the device can be facilitated. Further, it is not necessary to provide a structure for adjusting the relative positional relationship between the semiconductor laser device 13 and the optical fiber 27 in the chip carrier 21, and the configuration can be simplified. Furthermore, since the spot size is close to the semiconductor laser element 13 and the optical fiber 27 having a high relative refractive index difference is used,
The transmission efficiency of laser light can be improved. That is,
According to the above assembling method, even in the case of the optical fiber 27 whose spot size is close to the semiconductor laser element 13, it is possible to easily adjust the optical fiber 27 to a mounting state with high coupling efficiency.

Embodiment 7 FIG. Next, FIG. 13 is a sectional view of a principal part of a semiconductor laser device according to a seventh embodiment of the present invention, and FIG. 14 is a sectional view taken along line XIV-XIV of FIG. In the figure, a chip carrier 31 on which a semiconductor laser element 13 is mounted is provided with a groove 31a having a V-shaped cross section.
An optical fiber chip 32 as a spot size converter is provided in the groove 31a. The optical fiber chip 32 includes a chip body 33 having a circular cross section and a part of the outer circumferential surface of the chip body 33 in a circumferential direction (here, a substantially half circumferential part).
And a projecting portion 34 attached to the core, so that the core as a whole has a cross-sectional shape in which the center of the core is eccentric.
At the output end of the chip body 33, a converter 33a for increasing the spot size of the laser beam is provided.

When assembling such a semiconductor laser device, the semiconductor laser device 13 is fixed to the chip carrier 31 and the optical fiber chip 32 emitted from the semiconductor laser device 13 is placed in a state where the optical fiber chip 32 is placed in the groove 31a. While detecting the level of the laser light passing through the groove 3
The optical fiber chip 32 is rotated in the direction of the arrow in FIG.

FIG. 15 shows the optical waveguide 14 of the semiconductor laser device 13 when the optical fiber chip 32 of FIG. 14 is rotated.
FIG. 4 is an explanatory diagram showing the relationship between the center of the optical fiber chip 32 and the center of the optical fiber chip 32. When the optical fiber chip 32 is rotated by 90 °, the core center is displaced between the positions 35a to 35d. Of these four positions, the position 35a is closest to the center 36 of the optical waveguide 14, so that when the core center is at the position 35a, the level of the detected laser beam is the highest.

As described above, in the state where the optical fiber chip 32 is rotated to the angle at which the level of the laser beam is the highest, FIG.
As shown in FIG. 6, the optical fiber chip 32 is sandwiched between the chip carrier 31 and the pressing plate 37, and the optical fiber chip 32 is fixed in the groove 31a in a state where the rotation is restricted.

In such a semiconductor laser device, after the optical fiber chip 32 is placed in the groove 31a without any adjustment with a predetermined precision, the optical fiber chip 32 is rotated in the groove 31a, so that the optical fiber chip 32 Since the position of the center of the core can be adjusted, the coupling efficiency of the laser light can be easily improved, and the assembly of the device can be facilitated. Further, it is not necessary to provide a structure for adjusting the relative positional relationship between the semiconductor laser device 13 and the optical fiber chip 32 in the chip carrier 21, and the configuration can be simplified.

The protrusion 34 can be easily formed by attaching a dielectric, a semiconductor, an organic substance, a metal, or the like to the surface of the chip body 33. In addition, a method such as vapor deposition, sputtering, plating, or coating can be appropriately selected as a method of attachment, and a precise control of the amount of protrusion on the order of submicrons is possible.

Embodiment 8 FIG. Next, FIG. 17 is a sectional view of a principal part of a semiconductor laser device according to an eighth embodiment of the present invention, and FIG. 18 is a sectional view taken along line XVIII-XVIII of FIG. In the seventh embodiment, the projection 34 is provided to decenter the center of the core. However, the optical fiber chip 41 of the eighth embodiment has a cross-sectional shape in which a part of the circular cross section in the circumferential direction is removed. Thereby, the center of the core is eccentric.

When assembling such a semiconductor laser device, the semiconductor laser device 13 is fixed to the chip carrier 31 and the optical fiber chip 41 emitted from the semiconductor laser device 13 is placed in the state where the optical fiber chip 41 is placed in the groove 31a. While detecting the level of the laser light passing through the groove 3
The optical fiber chip 41 is continuously rotated in the direction of the arrow in FIG.

FIG. 19 shows the optical waveguide 14 of the semiconductor laser device 13 when the optical fiber chip 41 of FIG. 18 is rotated.
FIG. 5 is an explanatory diagram showing a relationship between the center of the optical fiber chip 41 and the center of the optical fiber chip 41. When the optical fiber chip 41 is rotated, the center of the core is displaced along a locus 42 in FIG.
Of the points on this trajectory, the level of the detected laser beam becomes highest when the core center moves to the position closest to the center 36 of the optical waveguide 14.

As described above, in a state where the optical fiber chip 41 is rotated to the angle at which the level of the laser beam is the highest, the optical fiber chip 41 is fixed in the groove 31a by, for example, the pressing plate 37 similar to FIG.

In such a semiconductor laser device, after the optical fiber chip 41 is placed in the groove 31a without any adjustment with a predetermined precision, the optical fiber chip 41 is rotated in the groove 31a, so that the optical fiber chip 41 is rotated. Since the position of the center of the core can be adjusted, the coupling efficiency of the laser light can be easily improved, and the assembly of the device can be facilitated. Further, it is not necessary to provide a structure for adjusting the relative positional relationship between the semiconductor laser element 13 and the optical fiber chip 41 in the chip carrier 21, and the configuration can be simplified.

[0066]

As described above, the semiconductor laser device according to the first aspect of the present invention is provided with the spot size converter for enlarging the spot size of the laser light emitted from the semiconductor laser element. The divergence angle of the laser light emitted from the lens can be reduced, whereby the aperture diameter of the lens can be reduced, and the entire apparatus can be downsized. Further, a change in optical output with respect to a change in the relative position of the component can be reduced, and reliability can be improved. Furthermore, the position dependency of the optical output when attaching the optical fiber is small, and the coupling efficiency can be further improved.

In the semiconductor laser device according to the second aspect of the present invention, since the semiconductor laser device and the spot size converter are integrated to constitute a semiconductor laser device with a converter, the overall size can be further reduced.

In the semiconductor laser device according to the third aspect of the present invention, since the optical fiber chip is used as the spot size converter, the coupling efficiency can be improved while miniaturizing the device.

According to the semiconductor laser device of the fourth aspect of the present invention, since the conversion portion is formed by enlarging the core diameter by thermal diffusion,
The spot size can be easily enlarged by a simple structure.

In the semiconductor laser device according to the fifth aspect of the present invention, the lens portion is provided on the input side end face of the optical fiber chip.
The efficiency of coupling laser light from the semiconductor laser element to the optical fiber chip can be improved.

In the semiconductor laser device according to the sixth aspect of the present invention, since the antireflection film is provided on the output end face of the optical fiber chip, the amount of reflected light returning from the output end face can be reduced, and the overall noise of the device is reduced. And high stability can be achieved.

In the semiconductor laser device according to the seventh aspect of the present invention, the output end face of the optical fiber chip is inclined with respect to a plane perpendicular to the axis of the optical fiber chip, so that reflected return light from the output end face is reduced. Therefore, low noise and high stability of the entire device can be achieved.

The semiconductor laser device according to the eighth aspect of the present invention uses an optical fiber chip having a cross-sectional shape in which the center of the core is eccentric, so that the position of the center of the core can be adjusted by rotating the optical fiber chip. The coupling efficiency of the laser beam can be easily improved, and the device can be easily assembled.

In the semiconductor laser device according to the ninth aspect of the present invention, since the projecting portion is provided on a part of the outer peripheral surface of the chip body having a circular cross section in the circumferential direction, the center of the core can be easily decentered.

A semiconductor laser device according to a tenth aspect of the present invention
Since an optical fiber chip having a cross-sectional shape in which a part of the circular cross section in the circumferential direction is removed is used, the center of the core can be easily decentered.

According to an eleventh aspect of the present invention, in the method of assembling a semiconductor laser device, the optical fiber chip is mounted on the chip carrier without any adjustment with a predetermined accuracy, and then only the input end of the optical fiber chip is deformed. Since the input side end face can be fixed at the optimum coupling position, the coupling efficiency of the laser beam can be easily improved, and the assembly of the device can be facilitated. Further, it is not necessary to provide a structure for adjusting the relative positional relationship between the semiconductor laser element and the optical fiber chip in the chip carrier, and the configuration can be simplified.

According to a twelfth aspect of the present invention, in the method of assembling a semiconductor laser device, the optical fiber is mounted on the chip carrier without any adjustment with a predetermined accuracy, and then only the input end of the optical fiber is deformed to thereby adjust the input side. Since the end face can be fixed at the optimum coupling position, the coupling efficiency of the laser beam can be easily improved, and the assembly of the device can be facilitated. Further, it is not necessary to provide a structure for adjusting the relative positional relationship between the semiconductor laser element and the optical fiber in the chip carrier, and the configuration can be simplified.

In the method for assembling a semiconductor laser device according to the thirteenth aspect of the present invention, since the input side end is heated using a carbon dioxide gas laser, it can be easily heated in a short time.

In the method for assembling a semiconductor laser device according to the fourteenth aspect of the present invention, since the input side end is heated using the electrode discharge, the heating can be easily performed in a short time.

In the method for assembling a semiconductor laser device according to the fifteenth aspect, since the input side end is heated using the micro burner, the heating can be easily performed in a short time.

In the method for assembling a semiconductor laser device according to the present invention, the optical fiber chip is placed in the groove without any adjustment with a predetermined accuracy, and then the optical fiber chip is rotated in the groove. Since the position of the center of the core can be adjusted, the coupling efficiency of the laser beam can be easily improved, and the assembly of the device can be facilitated. Further, it is not necessary to provide a structure for adjusting the relative positional relationship between the semiconductor laser element and the optical fiber chip in the chip carrier, and the configuration can be simplified.

[Brief description of the drawings]

FIG. 1 is a sectional view of a semiconductor laser device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a semiconductor laser device according to a second embodiment of the present invention;

FIG. 3 is a fragmentary cross-sectional view of a semiconductor laser device according to Embodiment 3 of the present invention;

FIG. 4 is a sectional view illustrating a method of assembling a semiconductor laser device according to a fourth embodiment of the present invention;

FIG. 5 is a cross-sectional view showing a state after the step shown in FIG. 4;

FIG. 6 is a cross-sectional view showing a state subsequent to FIG. 5;

FIG. 7 is a sectional view showing a method of assembling a semiconductor laser device according to a fifth embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a state after the step shown in FIG. 7;

FIG. 9 is a cross-sectional view showing a state after the step shown in FIG. 8;

FIG. 10 is a sectional view showing a method of assembling a semiconductor laser device according to a sixth embodiment of the present invention.

FIG. 11 is a cross-sectional view showing a state subsequent to FIG. 10;

FIG. 12 is a cross-sectional view showing a state subsequent to FIG. 11;

FIG. 13 is a sectional view of a main part of a semiconductor laser device according to a seventh embodiment of the present invention.

14 is a sectional view taken along line XIV-XIV in FIG.

FIG. 15 is an explanatory diagram showing a relationship between the center of the optical waveguide of the semiconductor laser device and the center of the core of the optical fiber chip when the optical fiber chip of FIG. 14 is rotated.

16 is a cross-sectional view showing a state where the optical fiber chip of FIG. 14 is fixed to a chip carrier.

FIG. 17 is a fragmentary cross-sectional view of a semiconductor laser device according to Embodiment 8 of the present invention;

18 is a sectional view taken along line XVIII-XVIII in FIG.

FIG. 19 is an explanatory diagram showing the relationship between the center of the optical waveguide of the semiconductor laser device and the center of the core of the optical fiber chip when the optical fiber chip of FIG. 18 is rotated.

FIG. 20 is a sectional view of an example of a conventional semiconductor laser device.

[Explanation of symbols]

7, 26, 27 optical fiber, 13 semiconductor laser device, 15 spot size converter, 17 semiconductor laser device with converter, 18 laser light, 19 lens, 2
2, 24, 32, 41 optical fiber chip, 22a lens unit, 23 antireflection film, 24a, 33a conversion unit,
24b emission side end face, 31a groove, 33 chip body,
34 Projection.

Claims (16)

[Claims] 1. A semiconductor laser device for emitting a laser beam, a spot size converter for expanding a spot size of the laser beam emitted from the semiconductor laser device, and a laser beam passing through the spot size converter A semiconductor laser device, comprising: a lens that emits laser light condensed by the lens; 2. The semiconductor laser device according to claim 1, wherein the semiconductor laser device and the spot size converter are integrated to constitute a semiconductor laser device with a converter. 3. The spot size converter according to claim 1, wherein the input side end faces the semiconductor laser element, and the conversion section for expanding the spot size of the laser beam is an optical fiber chip provided at the output side end. 2. The semiconductor laser device according to claim 1, wherein: 4. The semiconductor laser device according to claim 3, wherein the converter is formed by enlarging the core diameter by thermal diffusion. 5. The semiconductor laser device according to claim 3, wherein a lens portion is provided on an input end face of the optical fiber chip. 6. The semiconductor laser device according to claim 3, wherein an antireflection film is provided on an output end face of the optical fiber chip. 7. The semiconductor laser according to claim 3, wherein an output end face of the optical fiber chip is inclined with respect to a plane perpendicular to an axis of the optical fiber chip. apparatus. 8. The semiconductor laser device according to claim 3, wherein the optical fiber chip has a cross-sectional shape in which the center of the core is eccentric. 9. The optical fiber chip according to claim 8, wherein the optical fiber chip has a chip main body having a circular cross section and a protrusion attached to a part of an outer peripheral surface of the chip main body in a circumferential direction. 13. The semiconductor laser device according to claim 1. 10. The semiconductor laser device according to claim 8, wherein the optical fiber chip has a cross-sectional shape in which a part of a circular cross section in a circumferential direction is removed. 11. An optical fiber chip provided with a conversion section for expanding a spot size of laser light at an output end, and an axial direction from the input end face such that the input end face faces the semiconductor laser element. Fixing the chip to the chip carrier at positions spaced apart from each other, while detecting the output of the laser light emitted from the semiconductor laser element and passing through the optical fiber chip, deforming the input end of the optical fiber chip, A step of displacing the input-side end face, and a step of heating and partially melting the input-side end part, and then cooling to fix the position of the input-side end face. A method for assembling a semiconductor laser device. 12. A step of fixing an optical fiber to a chip carrier at a position axially spaced from the input side end face such that an input side end face thereof is opposed to the semiconductor laser element, wherein the light is emitted from the semiconductor laser element. A step of deforming the input end of the optical fiber and displacing the input end while detecting the output of the laser light passing through the optical fiber, and partially heating and partially heating the input end. A method of assembling a semiconductor laser device, comprising a step of fixing the position of the input side end face by cooling after melting. 13. The heating device according to claim 11, wherein the input side end is heated by using a carbon dioxide gas laser.
3. The method for assembling a semiconductor laser device according to item 2. 14. The method for assembling a semiconductor laser device according to claim 11, wherein the heating of the input side end is performed by using an electrode discharge. 15. The heating device according to claim 11, wherein the input side end is heated using a micro burner.
3. The method for assembling a semiconductor laser device according to item 2. 16. An optical fiber chip having a conversion section for enlarging a spot size of a laser beam provided at an output end and having a cross-sectional shape whose core center is eccentric, and an input end face of which is a semiconductor. Arranging the optical fiber chip in the groove while detecting the output of laser light emitted from the semiconductor laser element and passing through the optical fiber chip; Rotating the optical fiber chip, and fixing the optical fiber chip in the groove while restraining the rotation of the optical fiber chip.