JPH11340574A - Optical semiconductor device and optical semiconductor element incorporated in the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the output light of a semiconductor laser element by arranging a pair of wave front conversion elements which converts the optical path of light beams emitted from ends of an optical semiconductor element into a package, and radiating the light beams outwards from a light transmission window. SOLUTION: Structure, where two light beams 2 are reflected in a pair of wave front conversion elements 3 and are reflected in the same direction at emitting of the light beams 2 from the end faces of an optical waveguide 4 as the end faces of an optical semiconductor element 1 formed of an end face light-emitting type optical semiconductor element, is installed in a package. Namely, the optical semiconductor element 1 is fixed to the flat recessed base 7 of the recessed part 6 of a supporting block 5, and the light beams 2 are emitted from the end faces so that they follow the recessed base 7 from the end faces. The wave front conversion elements 3 are inclined and arranged on the sides of the recessed part 6, at which the light beams 2 arrive. The beams 2 are made to be radiated outwards from the light transmission window. Thus, increase in the output light of the optical semiconductor element 1 can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical semiconductor device and an optical semiconductor device incorporated in the device, and more particularly to a technology effective when applied to a manufacturing technology of a semiconductor laser device in which a laser beam has two beams or a high light output. .

[0002]

2. Description of the Related Art Semiconductor lasers are widely used as light sources for optical communications and information equipment.

A Fabry-Perot type semiconductor laser, which is an edge emitting type optical element, has a structure in which laser light is emitted from both ends of a semiconductor laser element (semiconductor laser chip).

On the other hand, a semiconductor laser array (multi-beam laser) that emits a plurality of laser beams is known as one of the semiconductor lasers. The semiconductor laser array device has a structure in which a semiconductor laser chip or a plurality of semiconductor laser chips formed monolithically on a compound semiconductor substrate (hereinafter also simply referred to as a semiconductor substrate) are incorporated in a single package.

The semiconductor laser array is described in, for example, "Electronic Materials", June 1987, p.
It is described in P111. This document discloses a monolithic three-beam semiconductor laser device. This document describes a visible light semiconductor laser as a signal reading light source used for a document file system, such as a CD, a VD device, a laser printer, a POS, a barcode reader, and the like.

[0006]

In the case of a monolithic semiconductor laser chip having one optical waveguide, laser light emitted from an emission surface at one end of the chip (forward emission light: output light)
Are used as light sources of various devices, and laser light (backward emitted light) emitted from the other emission surface is used as monitor light.

The present inventor has made the present invention as a result of studying whether backward emitted light can be used as a light source for various devices.

An object of the present invention is to provide a semiconductor laser device capable of achieving an increase in output light and a semiconductor laser device incorporating the semiconductor laser device.

On the other hand, a laser beam printer (LBP),
To speed up optical disks, magneto-optical disks, etc.,
It is known to convert a semiconductor laser serving as a light source into a multi-beam. The inventor of the present invention has realized that multi-beam formation can be achieved by forward emission light and rear emission light, and has made the present invention.

Another object of the present invention is to provide a semiconductor laser device capable of achieving multi-beams and a semiconductor laser device incorporating the semiconductor laser device.

[0011] The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0012]

The following is a brief description of an outline of typical inventions disclosed in the present application.

(1) A package having a light transmitting window for emitting light, an edge-emitting optical semiconductor element (semiconductor laser element) disposed in the package and emitting light (laser light) from both end faces, A lead formed over the inside and outside of the package, and connection means for electrically connecting an electrode of the optical semiconductor element to the lead, wherein the light emitted from an end face of the optical semiconductor element is An optical semiconductor device for emitting light from a transmission window to the outside, wherein a pair of wavefront conversion elements (mirrors) for converting an optical path of light emitted from both ends of the optical semiconductor element are arranged in the package, and the light is converted to the light. It is configured to radiate out of the transmission window.
The pair of wavefront conversion elements are configured to emit light emitted from both ends of the optical semiconductor element as non-intersecting radiation including parallel light. A light receiving element is arranged in the package, and the one wavefront conversion element has a structure for transmitting light, and the transmitted light is detected by the light receiving element. The light outputs of the two lights emitted from the light transmission window have the same light output.

An optical semiconductor element incorporated in such an optical semiconductor device is an optical semiconductor element that emits light from both ends of at least one optical waveguide. It is configured to have the same output, or a reflection film is provided on the exit surface, and the reflectance of the reflection film on the one exit surface is different from the reflection film ratio of the reflection film on the other exit surface. The light output on the side monitoring is higher than the light output on the other side.

(2) In the configuration of the means (1), the light emitted from both ends of the optical semiconductor element is focused by a wavefront conversion element.

According to the means (1), (a) the laser light emitted from both end faces of the semiconductor laser element is emitted in the same direction by a pair of wavefront conversion elements (mirrors), so that one light guide is provided. A two-beam configuration can also be used in the waveguide configuration. Therefore, for example, when used as a light source for a laser beam printer, the width of visualization by a laser beam on a photosensitive drum is twice as large as one laser beam,
Printer time can be reduced.

(B) One of the two wavefront conversion elements has a structure for transmitting light, and the transmitted light is detected by the light receiving element, so that the light output can be monitored.

(C) Since light emitted from both end faces of the optical semiconductor element can be used as output light, the light output can be improved.

(D) It is possible to further increase the number of beams by using an optical semiconductor device having a plurality of optical waveguides.

According to the means (2), the light emitted in the same direction is converged, so that it can be used as a spot light and its light output is increased.

[0021]

Embodiments and examples of the present invention will be described below in detail with reference to the drawings. In all the drawings for describing the embodiments and examples of the present invention, components having the same function are denoted by the same reference numerals, and the repeated description thereof will be omitted.

Before explaining each embodiment, FIG.
The principle configuration of the optical semiconductor device of the present invention will be described with reference to (a) to (c).

As shown in FIGS. 1 (a) to 1 (c), the optical semiconductor device of the present invention comprises an optical semiconductor device 1 comprising an edge emitting type optical semiconductor device.
The light 2 is emitted from both end faces of the light-emitting device, and these two lights (light flux: beam) 2 are reflected by a pair of wavefront conversion elements 3 and emitted in the same direction.

That is, the optical semiconductor element 1 is fixed to the flat recessed bottom surface 7 of the recess 6 of the support block 5 and emits light 2 from both end faces along the recessed bottom surface 7. Also,
The wavefront conversion elements 3 are respectively arranged on the side surfaces of the depression 6 where the light 2 reaches, at an angle. This wavefront conversion element 3 is constituted by, for example, a plane mirror.

FIG. 1A shows an example in which two light beams 2 are emitted as radiation beams which do not intersect each other, FIG. 1B shows an example in which parallel light beams are emitted, and FIG. This is an example.

According to the present invention, the light 2 emitted from both end faces of the optical semiconductor element 1 is radiated in the same direction by using the wavefront conversion element 3, so that even one optical waveguide 4 can be used as output light. Two beams can be obtained. That is, multiple beams of the number of the optical waveguides 4 can be obtained as output light. In the case of FIG. 1B, parallel light can be obtained, and in the case of FIG. 1C, focused light can be obtained. In any case, the light output can be increased.

Further, as an edge emitting type optical semiconductor device,
Semiconductor lasers (laser diodes) and light emitting diodes can be used. In the following embodiments, examples applied to a semiconductor laser will be described.

(Embodiment 1) FIGS. 2 to 4 relate to a semiconductor laser device according to an embodiment (Embodiment 1) of the present invention, and FIG. 2 shows a state where a part of the semiconductor laser device is cut away. FIG. 3 is a schematic view showing a positional relationship between a semiconductor laser element, a wavefront conversion element, a light receiving element, and the like, and FIG.
FIG. 3 is an enlarged perspective view showing a support structure for a semiconductor laser device or the like.

In the first embodiment, an example in which the present invention is applied to a semiconductor laser device which is an edge emitting type optical semiconductor device as an optical semiconductor device will be described. In the first embodiment, an example in which light is emitted in a parallel light state will be described.

As shown in FIG. 2, the semiconductor laser device 10 has a package body (stem) 11 as a main component of the assembly, and a lid (cap) 12 attached to the surface of the stem 11. I have. Package is
It is formed by the stem 11 and the cap 12.

The stem 11 is made of a circular metal plate having a thickness of several mm as shown in FIG. A copper heat sink 13 is fixed to the center of the upper surface of the stem 11 with a brazing material or the like.

A support block 5 made of a material that transmits light, such as silicon, is fixed to the upper surface of the heat sink 13. The support block 5 has a depression 6. The bottom surface 7 of the recess 6 is flattened, and the semiconductor laser element 1a is fixed.

The semiconductor laser device 1a has, for example, a length (depth) of 250 μm along the extending direction of the optical waveguide,
The optical waveguide 4 is formed of a rectangular body having a width of 300 μm and a thickness of 100 μm, and a depth of several microns from the upper surface.
(See FIG. 3). Although not shown, electrodes (anode electrode, cathode electrode) are provided on the upper and lower surfaces of the semiconductor laser device 1a. When a predetermined voltage is applied to these electrodes, light 2 (laser light 2 a) is emitted from both end faces of the optical waveguide 4.

Although not shown, a metallized layer is formed on the concave bottom surface 7, and the semiconductor laser device 1a is fixed to the metallized layer via a conductive adhesive. Therefore, the lower electrode of the semiconductor laser device 1a is electrically connected to the stem 11.

Also, three metal leads 14 penetrate the stem 11 so as to surround the heat sink 13.
It is fixed to. These leads 14 are supported by the stem 11 via an insulator 15 and are electrically independent of each other. Also, one lead 14 is mechanically and electrically connected to the back side of the stem 11 in an abutting state. These four leads 14 are connected to the semiconductor laser device 1.
0 is used as an external terminal, two are used as an anode electrode and a cathode electrode of the semiconductor laser element 1a, and the other two are used as an anode electrode and a cathode electrode of a light receiving element for monitoring light output.

Both side surfaces of the depression 6 of the support block 5 are inclined surfaces, on which a reflection film constituting a plane mirror 3 a as the wavefront conversion element 3 is deposited. The inclination angles of these inclined surfaces with respect to the concave bottom surface 7 are α and β. In the first embodiment, α = β = 45 °. Therefore, the angle γ between the two inclined surfaces becomes 90 °, and the laser light 2a emitted from both end surfaces of the optical waveguide 4 of the semiconductor laser device 1a becomes parallel light and is emitted in the same direction.

In the first embodiment, since the support block 5 is transparent (the absorptivity of light with respect to the wavelength of the laser light is suppressed at least lower than that of the plane mirror 3a),
If the reflectivity of the plane mirror 3a is appropriately selected for the material and thickness of the reflective film material constituting the plane mirror 3a, light transmission becomes possible. Therefore, in order to minimize light loss, one of the plane mirrors 3a
Is reflected, and the other plane mirror 3a transmits a part of light. The transmitted light 30 is received by the light receiving element 31, and the light output is monitored.

The degree of light reflection and light transmission by the above-mentioned reflective film is adjusted by, for example, setting the thickness of silicon oxide (SiO ₂ ) constituting the reflective film.

The semiconductor laser device 1a comprises an optical waveguide 4
Reflecting films 9a and 9b are provided on both end surfaces to protect the end surfaces and set the output light output. In the first embodiment, 2
The laser beam 2a of the beam has the same output. That is, the reflectance of the reflection film on one of the emission surfaces of the semiconductor laser device 1a is different from the reflectance of the reflection film on the other emission surface, and the light output on the side that monitors the light output is higher than the light output on the other side. Is also getting bigger. The reflectance of the reflection films 9a and 9b is low on the side (reflection film 9b) for monitoring the light output, and the reflection film 9a
The light output on the side becomes the laser light 2a, and the light output on the reflection film 9b side becomes the light output necessary to produce the laser light 2a and the transmitted light 30. Thus, the reflection films 9a and 9b can be appropriately selected.

If the light output is not monitored, the semiconductor laser element 1a may be configured so that the light output of the light emitted from both emission surfaces is the same. That is, the reflectance of the reflection films 9a and 9b becomes the same.

On the other hand, as shown in FIGS. 2 and 4, the light receiving element 31 is fixed to the tip of one lead 14 projecting from the upper surface of the stem 11 via a conductive adhesive (not shown). The transmitted light 30 transmitted through the support block 5 is received. The lower electrode of the light receiving element 31 is also electrically connected to the lead 14 via the adhesive.

As shown in FIG. 4, the upper electrodes of the semiconductor laser element 1a and the light receiving element 31 are fixed to end faces of leads 14 projecting from the upper surface of the stem 11 via conductive wires 32. .

On the other hand, the cap 12 has a light transmitting window 40 for transmitting the laser beam 2a at the center thereof. The light transmission window 40 is formed by overlapping and fixing a transparent glass plate 41 on a hole provided in the cap 12.

In such a semiconductor laser device 10, by applying a predetermined voltage to each of the predetermined leads 14, the semiconductor laser element 1a is operated to transmit two beams of laser light 2a parallel to each other. It can radiate from the window 40. The light output can be monitored by the light receiving element 31.

FIG. 5 is a partial schematic view showing a state where the semiconductor laser device of the first embodiment is incorporated in a laser beam printer.

The two laser beams 2 a emitted from the semiconductor laser device 10 are reflected by a polygon mirror 50 whose rotation is controlled, and are condensed on the surface of a photosensitive drum 52 of a laser beam printer through an fθ lens 51. The two laser beams 2a are scanned along the axial direction of the photosensitive drum 52. Further, the photosensitive drum 52 rotates.

Since the photosensitive drum 52 is uniformly charged before writing, the portion irradiated with the laser beam 2a loses its potential, and carbon powder (toner) adheres to the portion to be developed. . A laser beam printer is performed by copying the toner onto paper by electrostatic force at a transfer portion (not shown).

The semiconductor laser device 10 has two laser beams 2
Since a (laser beam) is emitted, a wide image can be visualized by two laser beams in one scan, and the printing time of a predetermined line is halved compared to the case of one laser beam. Become.

According to the semiconductor laser device of the first embodiment, the following effects can be obtained.

(1) The laser beams 2a emitted from both end faces of the semiconductor laser element 1a are emitted in the same direction by the pair of plane mirrors 3a, so that a two-beam configuration can be used even with a single optical waveguide configuration. So, for example,
When used as a light source for a laser beam printer, the width of visualization by the laser beam on the photosensitive drum 52 is twice as large as that of one laser beam, and the printer time can be reduced.

(2) One of the two plane mirrors 3a has a structure for transmitting light, and the transmitted light 30 is detected by the light receiving element 31, so that the light output can be monitored.

(3) Since the laser light 2a emitted from both end faces of the semiconductor laser element 1a can be used as output light, the light output can be improved.

(4) It is possible to further increase the number of beams by using a semiconductor laser device having a plurality of optical waveguides.

In the first embodiment, two beams of laser light 2a
Is a parallel light, but may be a radiated light that does not cross each other.

(Embodiment 2) FIG. 6 is a schematic view showing a part of a semiconductor laser device according to another embodiment (Embodiment 2) of the present invention.

The semiconductor laser device according to the second embodiment has the structure shown in FIG.
The laser beam 2a emitted from both end faces of the semiconductor laser element 1a intersects (intersection 60) by setting the angle of inclination of the plane mirror 3a. . In this case, spot light 61 is formed at the intersection 60, and the spot light 61 can be used as a light source for various devices using the spot light 61 as a light source.

FIG. 7 shows a semiconductor laser device 1 according to the second embodiment.
FIG. 2 is a schematic diagram showing a pickup unit of an optical disk system incorporating the optical disc system 0.

That is, the two laser beams 2 a emitted from the semiconductor laser device 10 are converged to form a spot beam 61. The spot light 61 passes through a collimating lens 62, a polarizing beam splitter 63, a quarter-wave (λ / 4) plate 64, and an objective lens 65, and reaches an optical disk 66.

The light reflected by the information recording portion of the optical disk 66 passes through the objective lens 65, the quarter-wave plate 64, and the optical path is bent at a right angle by the polarizing beam splitter 63.
After passing through the converging lens 67 and the cylindrical lens 68,
The light reaches the photodetector 69.

By using the semiconductor laser device 10 of the first embodiment, the spot light 61 having a high light output can be used as a light source.

(Embodiment 3) FIG. 8 is a plan view of a partially cut-away semiconductor laser device according to another embodiment (Embodiment 3) of the present invention.

The relationship between the optical semiconductor device 1 and the wavefront conversion device 3 according to the third embodiment is such that parallel light is emitted as shown in FIG. 1B, and the package is box-shaped and used as a light source for optical communication. It is an example.

The package comprises a package body 11 having a box structure with an open upper part, and a plate-like lid 12 for closing the package body 11. Two optical fiber cables 70 are guided to one end of the package body 11. A cylindrical fiber guide 71 is provided.

A conductive heat sink 13 is provided at the center of the package body 11, and the support block 5 having the same structure as that of the first embodiment is fixed to the heat sink 13. However, in the case of the third embodiment,
The fixing surface is different from that of the first embodiment so that the laser beam 2a emitted from the semiconductor laser element 1a fixed to the support block 5 travels to the right side in the figure by the plane mirror 3a. The light receiving element 3 is provided on the heat sink 13.
A conductive support 72 to which 1 is fixed is fixed.

Each side of the package body 11 has four
The leads 14 are disposed in a penetrating state, and the inner ends of the predetermined leads 14 are electrically connected to the electrodes of the semiconductor laser element 1 a and the light receiving element 31 via conductive wires 32. It is connected.

The laser beam 2a traveling in parallel enters the tip of the optical fiber 75 covered by each fiber guide 71. Although not shown, the distal end of the optical fiber 75 is fixed to the heat sink 13 by a bonding material or the like.

According to the third embodiment, a single optical signal can be transmitted to a predetermined location via two optical fibers 75. In this case, the light output (light intensity) of the two-beam laser light 2a is the same.

Although the invention made by the inventor has been specifically described based on the embodiment, the invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the invention. Needless to say, for example, an edge emitting light emitting diode may be used as the optical semiconductor element. Further, the wavefront conversion element may be another optical element such as a prism.

[0069]

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

(1) The laser beams emitted from both end faces of the semiconductor laser element are emitted in the same direction by a pair of wavefront conversion elements, so that a two-beam configuration can be used even with a single optical waveguide configuration.

(2) Therefore, by increasing the number of optical waveguides, more beams can be obtained.

(3) If the two-beam semiconductor laser device according to the present invention is used as the light source of a laser beam printer, the width of the photosensitive drum on which the laser beam is visualized becomes twice as large as that of a single laser beam. Can be shortened.

(4) One of the two wavefront conversion elements has a structure for transmitting light, and since the transmitted light is detected by the light receiving element, the light output can be monitored.

(5) Since light emitted from both end faces of the optical semiconductor element can be used as output light, the light output can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a principle configuration of an optical semiconductor device of the present invention.

FIG. 2 is a perspective view showing a semiconductor laser device according to an embodiment (Embodiment 1) of the present invention, in which a part of the semiconductor laser device is cut away.

FIG. 3 is a schematic diagram illustrating a positional relationship between a semiconductor laser element, a wavefront conversion element, a light receiving element, and the like in the semiconductor laser device according to the first embodiment.

FIG. 4 is an enlarged perspective view showing a support structure for a semiconductor laser element and the like in the semiconductor laser device of the first embodiment.

FIG. 5 is a partial perspective view showing a state where the semiconductor laser device of the first embodiment is incorporated in a laser beam printer.

FIG. 6 is a schematic view showing a part of a semiconductor laser device according to another embodiment (Embodiment 2) of the present invention.

FIG. 7 is a schematic diagram showing a pickup unit of an optical disk system incorporating the semiconductor laser device of the second embodiment.

FIG. 8 is a plan view of a semiconductor laser device according to another embodiment (Embodiment 3) of the present invention, with a portion cut away.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical semiconductor element, 1a ... Semiconductor laser element, 2 ... Light,
2: luminous flux: beam, 3: wavefront conversion element, 3a: plane mirror,
DESCRIPTION OF SYMBOLS 4 ... Optical waveguide (resonator), 5 ... Support block, 6 ... Recess, 7 ... Recess bottom, 9a, 9b ... Reflection film, 10 ... Semiconductor laser device, 11 ... Package main body (stem), 12 ...
Lid (cap), 13 heat sink, 14 lead, 15 insulator, 30 transmitted light, 31 light receiving element, 3
2 ... wire, 40 ... light transmission window, 41 ... transparent glass plate, 5
0: polygon mirror, 51: fθ lens, 52: photosensitive drum, 60: intersection, 61: spot light, 62: collimating lens, 63: polarizing beam splitter, 64:
Quarter wavelength (λ / 4) plate, 65 ... objective lens, 66 ...
Optical disk, 67: converging lens, 68: cylindrical lens, 69: photodetector, 70: optical fiber cable,
71: Fiber guide, 72: Support, 75: Optical fiber.

Claims (7)

[Claims] 1. A package having a light-transmitting window for emitting light, an edge-emitting optical semiconductor element disposed in the package and emitting light from both end faces, and formed inside and outside the package. An optical semiconductor device, comprising: a lead; and connection means for electrically connecting an electrode of the optical semiconductor element and the lead, and radiating light emitted from an end face of the optical semiconductor element to the outside through the light transmitting window. In the package, a pair of wavefront conversion elements that convert an optical path of light emitted from both ends of the optical semiconductor element are arranged,
An optical semiconductor device configured to emit light from the light transmitting window to the outside. 2. The apparatus according to claim 1, wherein said pair of wavefront conversion elements are configured to emit light emitted from both ends of said optical semiconductor element as non-intersecting radiation including parallel light. 2. The optical semiconductor device according to 1. 3. The optical semiconductor device according to claim 1, wherein said pair of optical path conversion elements are configured to focus light emitted from both ends of said optical semiconductor element. 4. A light receiving element is arranged in the package, the one wavefront conversion element has a structure to transmit light, and the transmitted light is detected by the light receiving element. The optical semiconductor device according to claim 1, wherein: 5. The optical semiconductor according to claim 1, wherein the light outputs of the two lights emitted from the light transmission window have the same light output. apparatus. 6. The method according to claim 1, wherein
The optical semiconductor element incorporated in the optical semiconductor device according to the above paragraph, wherein the optical semiconductor element emits light from both ends of at least one optical waveguide, and the optical output of the light emitted from the both emission surfaces is the same. An optical semiconductor device, which is configured to be an output. 7. An optical semiconductor device incorporated in the optical semiconductor device according to claim 4 or 5, wherein the optical semiconductor device has at least one optical waveguide in which reflection films are provided on emission surfaces at both ends. The reflectance of the reflection film on the one emission surface and the reflectance of the reflection film on the other emission surface are different, and the light output on the side that monitors light output is larger than the light output on the other side. An optical semiconductor device, comprising: