JP2006126754A - Light emitting module, its manufacturing method, optical transceiver module, and optical communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting module which can connect a planar optical element with an optical fiber by bending it by 90°, without the need of increasing the number of components nor improving process controllability, and uses a surface emitting semiconductor laser capable of enhancing alignment accuracy and reducing cost, and also to provide the manufacturing method of this module and an optical communication system using this module. <P>SOLUTION: The light emitting module couples the light emitting element 1 of the surface emitting semiconductor laser having an oscillating wavelength of ≥1.1 μm and an optical fiber 2. This light emitting module is composed of a micro-lens 5 which is formed by machining an Si mono-crystal and collimates or condenses the vertically emitted light of the semiconductor laser element 1 to parallel light, a reflection prism 3 that uses as a reflection face the Si (111) face formed by machining the Si mono-crystal for the purpose of bending collimated or condensed light by nearly 90°, and an optical fiber guiding V-groove structure 4 formed on the Si (111) face, wherein the micro-lens 5, the reflection prism 3 and the guiding V-groove structure 4 are integrally formed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light emitting module using a surface emitting semiconductor laser, a method for manufacturing the light emitting module, and an optical communication apparatus using the light emitting module.

Conventionally, in light emitting devices, vertical cavity surface emitting lasers that emit light perpendicularly from the substrate surface can be improved in terms of reducing power consumption and cost of optical transmission modules. (For example, see Patent Documents 1 to 5).
Incidentally, in recent years, optical modules for high-speed optical connection have been developed. However, there are many problems regarding the coupling between the optical element and the optical transmission body such as an optical fiber, particularly from the viewpoint of cost reduction and high performance.
A surface emitting laser can be driven with a low threshold value of 1 mA or less, can perform wafer level inspection, and does not require cleavage accuracy, so that the cost can be reduced. In such optical coupling between a surface emitting laser and an optical fiber, passive alignment that performs alignment without operating an element is essential for cost reduction.
As a technique for that purpose, a method of producing and assembling a fixing member is generally used. However, the mechanical accuracy of the fixing member is required, the elastic coefficient and the thermal expansion coefficient are limited, and the number of parts is increased, so that cost reduction is difficult. In particular, when a plastic mold or the like is used for cost reduction, there is a problem that the yield of optical coupling and long-term reliability are lacking.
Therefore, a method has been proposed in which a guide hole for coupling with an optical fiber is produced with a processing accuracy of photolithography technology. For example, in Patent Documents 1 and 2, a hole for fixing an optical fiber on a substrate side on which a surface light receiving element or a light emitting element is manufactured has photosensitivity or electron beam curability and is patterned by photolithography. Is formed by a thick film material that can be selectively cured.
Also in Patent Document 3, a fusion layer having a predetermined film thickness is formed on the surface on which the surface emitting laser is installed, and the optical device is bonded to the end face of the optical fiber via the fusion layer. A method is disclosed. In these cases, the number of parts can be reduced and the assembly is very simple, so that the cost can be reduced.
JP 2002-33546 A JP 2002-214485 A JP 2002-107581 A JP 2001-141965 A JP-A-9-127375

However, when the guide hole is made of a thick film material, if the thick film material is thin, the controllability of the taper shape and the hole diameter is good, but the mechanical strength is insufficient. If the thick film material is thick, the mechanical strength is good. However, there is a problem that the controllability of the taper shape and the hole diameter is insufficient.
On the other hand, the method using the fusion layer has a disadvantage that it is difficult to align the light emitting point or the light receiving point with the optical fiber.
When the guide hole is made of a thick film material, the optical fiber is connected perpendicularly to the surface optical element in both methods using the fusion layer. Since an optical fiber cannot be bent rapidly, there is a problem that when it is applied to the connection within the same board, a large loop is formed on the board and a large space is occupied in the equipment.
Further, as a conventional general method, several methods for sequentially assembling a completed surface optical element, a mirror, and a fiber fixing material have been proposed (Patent Documents 4 and 5).
However, with these methods, it is possible to make the optical fiber coupling direction parallel to the substrate. However, the number of parts increases, the number of places where high-precision assembly of each part is required, and manufacturing is increased. Are difficult, and it takes a long time to assemble.
Therefore, in view of the above situation, an object of the present invention is a reflection inclined by 45 ° made of a Si (111) surface formed by Si anisotropic etching on a light emitting portion or a light receiving portion of a surface optical element. A prism structure, a V-groove structure for optical fiber guide made of Si (111) surface formed by Si anisotropic etching simultaneously with the reflecting prism structure, and a condensing microlens formed by micromachining are integrated. A surface optical element and optical fiber can be bent and connected by 90 ° without requiring an increase in the number of parts and process controllability, and the alignment accuracy can be improved and the cost can be reduced. An object of the present invention is to provide a light emitting module using a light emitting semiconductor laser, a method for manufacturing the light emitting module, and an optical communication device using the light emitting module.

In order to solve the above problems, the invention described in claim 1 is a light emitting module for coupling a light emitting element of a surface emitting semiconductor laser having an oscillation wavelength of 1.1 μm or more and an optical fiber. A microlens that is formed by processing and collimates or condenses light emitted in the vertical direction of the surface-emitting type semiconductor laser element into parallel light, and a Si single unit for bending the collimated or condensed light by approximately 90 °. A reflection prism having a Si (111) surface formed by processing a crystal as a reflection surface, and an optical fiber guide V-groove structure formed by the Si (111) surface, the microlens and the reflection The prism and the V-groove structure for optical fiber guide are integrally formed.
Note that “approximately 90 °” does not mean exactly 90 °, but includes values close to 90 °.
According to a second aspect of the present invention, there is provided a light emitting module for coupling each light emitting element of a surface emitting semiconductor laser array having an oscillation wavelength of 1.1 μm or more and an optical fiber, wherein the surface is formed by processing a Si single crystal. A microlens array that collimates or condenses light emitted vertically from each light emitting element of the light emitting semiconductor laser array into parallel light, and a Si single crystal is processed to bend the collimated or condensed light by approximately 90 °. And the optical lens guiding V-groove structure formed of the Si (111) surface and the microlens, the reflecting prism, and the guide V. The groove structure is integrally formed.
In a third aspect of the present invention, in the first or second aspect, the microlens, the reflecting prism, and the guide V-groove structure are inclined 9.7 ° from the (100) plane in the <110> direction. It is integrally formed on the same Si single crystal substrate having a surface.
The invention of claim 4 provides a step of preparing a first Si single crystal substrate having a surface inclined 9.7 ° from the (100) plane in the <110> direction, and a second Si single crystal substrate. A step of bonding the first and second Si single crystal substrates, a step of forming a reflecting prism and a guide V-groove structure on the surface side of the bonded first Si single crystal substrate, and a bonded second Forming a microlens on the surface of the Si single crystal substrate.

According to a fifth aspect of the present invention, in the light emitting module manufactured using the manufacturing method according to the fourth aspect, the second Si single crystal substrate has a crystal orientation different from that of the first Si single crystal substrate. And
A sixth aspect of the present invention is characterized in that, in the first to third or fifth aspect, the active layer of the surface emitting semiconductor laser is a III-V group mixed crystal semiconductor containing N and other V groups. To do.
According to a seventh aspect of the present invention, in any one of the first to third aspects or the fifth to sixth aspects, the distance between the microlens and the surface emitting semiconductor laser element is kept constant. It is characterized by having a maintenance structure integrally.
The invention according to claim 8 is characterized in that the optical fiber to be coupled is a single mode fiber, and the light emitting module according to any one of claims 1 to 3 or claims 5 to 7.
The invention according to claim 9 is characterized by an optical transceiver module using the light emitting module according to any one of claims 1 to 3 or claims 5 to 7.
According to a tenth aspect of the present invention, there is provided an optical communication system using the optical transceiver module according to the ninth aspect.

According to the present invention, a substantially 90 ° reflecting prism structure formed by Si anisotropic etching and a V-groove structure for an optical fiber guide formed by Si anisotropic etching on a surface emitting semiconductor laser element. A microlens made of single crystal silicon can be installed to connect a surface emitting semiconductor element and an optical fiber by bending 90 ° without increasing the number of parts and improving process controllability. Since it is collimated, the optical path length between the surface emitting semiconductor laser element and the optical fiber can be increased, and the degree of freedom in design increases.
Furthermore, the alignment accuracy is improved by forming the respective parts integrally. From this, it is possible to facilitate the fixing operation of the optical fiber, improve the productivity, and provide a light emitting module having a low cost structure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a top view showing an embodiment of a light emitting module according to the present invention. FIG. 2 is a side view of the light emitting module of FIG.
A characteristic configuration of this embodiment is that a light emitting element 1 of a surface emitting semiconductor laser having an oscillation wavelength of 1.1 μm or more (or each light emitting element of a surface emitting semiconductor laser array) and an optical fiber 2 are coupled. In the light-emitting module, the light emitted in the vertical direction of the surface-emitting semiconductor laser device 1 (or each light-emitting device of the surface-emitting semiconductor laser array) formed by processing a Si single crystal is collimated into parallel light or A condensing microlens 5; a reflecting prism 3 having a reflecting surface of a Si (111) surface formed by processing a Si single crystal to bend the light collimated or condensed by the microlens 5 by approximately 90 °; A V-groove structure for an optical fiber guide formed on a (111) plane, and a microlens 5, a reflecting prism 3, and a V-groove structure for an optical fiber guide. This is in that the object 4 is integrally formed.
That is, in this embodiment, a one-dimensional surface emitting semiconductor laser array is used. Each surface emitting semiconductor laser element 1 of the laser array has a mesa diameter of approximately 20 μm square and is formed side by side at a pitch of approximately 500 μm.
Note that “approximately 90 °” does not mean 90 ° just in a strict sense, but includes a case where it is bent to a value close to 90 ° (for example, a range of ± several degrees). In short, all the ranges that are appropriate as the bending angle of the condensed light within the range where the object and effect of the present invention are exhibited are included.
In the drawing, only the mesa shape of the surface-emitting type semiconductor laser device 1 is simply expressed. The electrode for the laser device is simply denoted by reference numeral 7 and the description is omitted. However, electrodes are formed on the back surface of the substrate and the upper part of the mesa, respectively, and a laser beam having a predetermined wavelength is emitted from the upper end of the mesa by injecting current into the electrodes.
The semiconductor laser element 1 uses GaInNAs that oscillates in the 1.3 μm band as an active layer. GaInNAs has a structure in which the band gap discontinuity of the conduction band can be made larger than that of GaInAsP that oscillates in the same 1.3 μm band.
This configuration is known to be capable of forming a quantum well structure, so that there is little deterioration in characteristics due to carrier overflow during high temperature operation. Therefore, it is considered that the operation with good characteristics can be performed without installing a cooling mechanism, and the cost can be reduced.
It is known that III-V mixed crystal semiconductors including N and other V groups have a conduction band level that decreases at a rate of about 150 meV per 1% of N added in a region where the N concentration is low. For example, a quantum well active layer composed of a combination with GaAs has a large band gap discontinuity in the conduction band and can easily take a structure in which carrier overflow does not easily occur.
The active layer in this case is not limited to GaInNAs, but the same effect can be seen even when a III-V mixed crystal semiconductor containing N and other V groups such as GaInNAsSb and GaInNAsP is used.

The surface-emitting type semiconductor laser element can be manufactured by epitaxial growth using, for example, metal organic chemical vapor deposition (MOCVD). By introducing a raw material (Group III organometallic material, Group V raw material, dopant, etc.) with a H ₂ carrier gas into a reaction tube maintained at a predetermined pressure (for example, 100 torr) and decomposing it on the substrate, for example, by heat, A predetermined semiconductor crystal can be epitaxially grown on the substrate.
This surface-emitting type semiconductor laser element is crystal-grown by the MOCVD method, but its structure can be produced by a method other than the MOCVD method, for example, the MBE method.
Thereafter, the laminated structure is etched into a columnar shape to a depth where element isolation is necessary, so that a mesa structure is formed. The mesa is protected by, for example, polyimide, an opening is provided in the upper part of the mesa, a light emitting part and an electrode are formed, and is configured as a surface emitting semiconductor laser element.
A Si (silicon) single crystal substrate 9 on which a microlens 5 for collimating laser light into substantially parallel light is formed at a position immediately above each semiconductor laser element 1.
Many methods for forming the microlens 5 on the Si single crystal substrate 9 with high accuracy have been proposed. For example, after the EB resist is applied to the Si substrate, the microlens 5 is exposed and developed while controlling the exposure amount with an EB exposure machine. After processing the EB resist into a lens shape, the selection ratio is 1: 1: Processing can be performed by a method such as dry etching in the vertical direction under the condition of 1.
Si is almost transparent to light in the 1.3 to 1.55 μm band used for optical communication and has a high refractive index. Furthermore, since the technology for processing the microlens shape is substantial as described above, it is suitable as a lens for collimating a 1.3 μm band laser beam, and an elliptical mirror is formed as in Patent Document 4. Therefore, it is more preferable because the processing accuracy can be higher than the method of condensing light.
In this embodiment, the microlens 5 is designed to collimate into parallel light. However, the microlens 5 should be a long-focusing condensing lens in which the laser beam is focused at the core of the optical fiber to be coupled. Therefore, it is possible to enhance the coupling with an optical fiber having a small core diameter such as a single mode fiber.
It is not difficult to form the microlenses 5 in the same shape by etching. For example, if the concave and convex portions for positioning are formed at the same time, the alignment can be facilitated.

In the present embodiment, a recess 9a is provided on the surface of the Si substrate 9 provided with the microlens 5, and the distance is made constant when the semiconductor laser element 1 and the collimating lens are combined.
Further, a step is provided in the concave portion, and the laser element substrate 6 of the surface emitting semiconductor laser element 1 is fitted into the step. At this time, by designing so that the position of the light emitting portion on the surface emitting semiconductor laser element substrate 9 attached in advance and the position of the microlens can be matched, the ease of alignment can be improved and the mounting accuracy can be improved. .
A part of the laser light collimated by the microlens 5 is changed in a right angle direction by the reflecting prism 3. The reflecting prism 3 is made by anisotropically etching a Si single crystal substrate 9. The reflecting prism portion 3 utilizes the (111) plane that appears when the Si single crystal substrate 9 is etched by anisotropic etching.
Further, on the Si single crystal substrate 9 on which the reflecting prism 3 is formed, a V-shaped groove is further formed by anisotropic etching, and is an optical fiber that couples with laser light emitted in the vertical direction. It is intended to serve as a guide when aligning.

FIG. 3 is a top view showing a method of forming a reflecting prism using a Si single crystal substrate. FIG. 4 is a side view of FIG. A method of forming the reflecting prism 3 using the Si single crystal substrate 9 will be described with reference to FIGS.
First, a Si (100) single crystal substrate 9 inclined by 9.7 ° in the <110> direction is prepared, and a prism forming stripe pattern 11 for an etching mask having a stripe shape perpendicular to the direction in which each side is inclined is prepared. Form.
In the present embodiment, a V-groove forming pattern 10 which is a mask pattern for forming a guide groove adjacent to the prism forming stripe pattern 11 is also formed at the same time to form a guide groove for an optical fiber (FIG. 3). ).
The V-shaped guide groove has a slight taper because the substrate is inclined with respect to the (100) plane. Due to this taper, the guide groove becomes thinner gradually as the distance from the prism side increases. For this reason, the optical fiber is inscribed in the groove at the furthest distance from the prism side of the guide groove, and the alignment is defined. Therefore, the groove is designed so that a groove corresponding to the diameter of the optical fiber can be formed with this width.
As a mask for anisotropic etching, a dielectric film such as Ta ₂ O ₅ or Si ₃ N ₄ is suitable. Further, since SiO ₂ formed by thermal oxidation or the like can be used as a mask, it is not necessary to form another film on the surface of the Si wafer with a thermal oxide film, so that the process can be simplified.
These etching masks can be easily made by patterning the film on the Si single crystal substrate 9 using photolithography and removing unnecessary portions by dry etching or the like. With the etching mask formed in this way, Si is etched by anisotropic etching.
In the case of the present embodiment, the etchant used was an approximately 15 wt% KOH aqueous solution heated to about 80 ° C. In addition, TMAH (tetramethylammonium hydroxide) or the like can be used as the etchant.
FIG. 5 is a top view showing the formation of a groove for guiding an optical fiber. FIG. 6 is a side view of FIG. When etching is performed using this etchant, the Si single crystal substrate 9 exhibits an etching rate ratio that varies remarkably depending on the plane orientation. In particular, the (111) plane having a slow etching rate is a slope with the stripe pattern 11 formed by the etching mask as the upper side. Appears (FIGS. 5 and 6).
In general, the (111) plane appearing during anisotropic etching is easy to obtain a surface property relatively close to a mirror by adjusting the etching conditions, and can be easily used as a reflective surface.

FIG. 7 is a top view showing the formation of a guide groove for an optical fiber. FIG. 8 is a side view of FIG. At the same time, after forming a dielectric film on the entire surface, patterning is performed as shown in FIGS. 3 to 6 to form a mask for the dielectric film, and anisotropic etching is performed to finally form FIGS. 7 and 8. Thus, the groove portion 4 for guiding the optical fiber can be formed.
The formed guide groove portion 4 is formed such that the Si (111) surface surrounds the bottom surface parallel to the surface of the Si single crystal substrate 9. In the present embodiment, the optical fiber 2 is formed so that the (111) surface and the bottom surface of the V-groove portion 4 are inscribed at the narrowest portion of the guide V-groove portion 4.
After the shape is completed in this way, in order to obtain a prism having the (111) surface as a reflecting surface, unnecessary (111) surface side is cut by dicing to bring out a vertical surface. Thus, the Si single crystal substrate 9 in which the reflecting prism 3 and the optical fiber alignment structure are integrally formed is completed.
The Si single crystal substrate 9 including the reflecting prism 3 made in this way is aligned with the microlens 5 for collimation and is made as an integral structure, but there are several possible methods.
For example, as one of them, a Si single crystal substrate for forming the microlens 5 is separately prepared and bonded by direct bonding or the like to the Si single crystal substrate 9 for integrally forming the reflecting prism 3 and the guide V groove portion 4. There is a method of forming.
In this method, when etching is performed at a relatively large depth, even if the strength of the normal Si single crystal substrate is insufficient, the Si single crystal substrate for microlenses is bonded to the Si single crystal substrate 9. By making the total of two sheets, the thickness can be doubled, so the problem of strength can be cleared.
In addition, since the orientation of each Si single crystal substrate may be different, there is an advantage that the degree of freedom is increased if an attempt is made to make a structure by performing anisotropic etching on the front and back of the substrate. At this time, an apparatus for bonding the substrates is required, but the substrate cost can be reduced because the thickness problem can be cleared even if a Si single crystal substrate having a normal thickness is used.

FIG. 9 is a schematic diagram for explaining alignment between the Si single crystal substrate on the microlens side and the Si single crystal substrate 9 on the reflecting prism side. Naturally, the pattern formation on the front and back sides is performed using the aligner for alignment on the back surface after bonding is performed before that, so the alignment between the microlens side and the reflecting prism side is performed with the accuracy of photolithography. It will be.
FIG. 10 is a schematic diagram for explaining the alignment between the microlens and the reflecting prism formed on the back surface of the same Si single crystal substrate. At this time, if the Si single crystal substrate has a sufficient thickness, a microlens can be formed on the back surface of the same Si single crystal substrate as the reflecting groove and the guide V-groove partial structure.
In order to form these integrated structures, naturally, an alignment aligner for the back surface is required. However, since each part is integrally formed with the accuracy of the photolithographic process of the semiconductor, a highly accurate module can be obtained.
The microlens, the reflecting prism, and the V-groove portion for guiding the optical fiber formed as described above are integrally formed, and the optical fiber is assembled to the module to which the surface emitting semiconductor laser is attached.
The optical fiber 2 (FIGS. 1 and 2) is aligned with high positional accuracy by being dropped by the guide V-groove portion 12 (FIG. 11) and attaching the tip surface to the vertical end surface of the reflecting prism 3 by abutment. It becomes possible.
At this time, the optical fiber can be easily fixed by fixing it with an adhesive resin or the like that is transparent to the laser beam so as to be filled between the reflecting prism 3 and the optical fiber 2 (see FIGS. 1 and 2). Is possible. In this embodiment, an ultraviolet curable resin is used. Furthermore, if the refractive index of the adhesive resin is close to Si, it is more preferable because the optical loss between the prism surface cut out by dicing and the end surface of the optical fiber can be reduced.
The crystal plane appearing by anisotropic etching as in this embodiment is uniquely determined by the crystal of the material, and is therefore a very suitable method for making a mirror with a highly precise angle. Furthermore, alignment can be facilitated even in an array module using a plurality of elements in parallel, and cost reduction can be achieved.
Furthermore, even if the optical fiber to be combined is a single mode fiber, it can be aligned relatively easily with sufficient accuracy, so that it is extremely useful for reducing the cost of a light emitting module using the single mode fiber.

When the configuration as described above is used, as shown in FIGS. 1 and 2, a surface emitting semiconductor laser array that oscillates at 1.3 μm or more, a microlens 5 formed on a Si single crystal substrate 9, and a Si single crystal. By combining with the reflecting prism 3 formed on the crystal substrate, the optical fiber 2 can be easily and accurately coupled, and a small light emitting module can be achieved at low cost.
In addition, the use of GaInNAs, which is a III-V mixed crystal semiconductor including N and other V group having excellent temperature characteristics, as the material of the active layer of the surface emitting semiconductor laser can eliminate a special cooling device. Therefore, it is possible to achieve a light emitting module with a small size and high performance at a lower cost.
Further, since the guide structure (V groove portion 12) for coupling with the optical fiber 2 is formed integrally with the reflecting prism 3 by using anisotropic etching, alignment becomes easy and the cost can be reduced. .
The reflecting prism 3 can easily obtain a highly accurate and highly reflective reflecting prism by using Si anisotropic etching, and an inexpensive and high-performance optical module can be achieved. ing.

From the above, the surface emitting semiconductor laser having an oscillation wavelength of 1.1 μm or more, and the light emitting module that couples the light emitting element of the surface emitting semiconductor laser and the optical fiber are formed by processing a Si single crystal. Si (111) formed by processing a Si single crystal to bend the collimated or condensed light by approximately 90 °, a lens that collimates or condenses the light emitted vertically from the semiconductor laser element into parallel light It is comprised from the reflecting prism which makes a surface a reflective surface, and the V-groove structure for optical fiber guides formed with Si (111) surface.
Therefore, since the lens, the reflecting prism, and the guide V-groove structure are integrally formed, it is possible to obtain a light emitting module that combines a highly accurate and low cost optical fiber with a surface emitting semiconductor laser.
The lens, reflecting prism, and guide V-groove structure are integrally formed on the same Si single crystal substrate having a surface inclined 9.7 ° from the (100) plane in the <110> direction. In addition, it is possible to obtain a light emitting module that combines a low-cost optical fiber and a surface emitting semiconductor laser or a laser array.
The light emitting module manufacturing method includes a step of preparing a first Si single crystal substrate having a surface inclined 9.7 ° from the (100) plane in the <110> direction, and a second Si single crystal substrate. A step of bonding the first and second Si single crystal substrates, a step of forming a reflecting prism and a guide V-groove structure on the surface side of the bonded first Si single crystal substrate, and a bonded second Forming a lens on the Si single crystal substrate surface side.
Therefore, it is possible to manufacture a light emitting module that combines an optical fiber having a sufficient strength and a surface emitting semiconductor laser or a laser array while performing etching to a sufficient depth even with a Si single crystal substrate having a normal thickness. .
In the light emitting module manufactured using the above manufacturing method, since the second Si single crystal substrate has a crystal orientation different from that of the first Si single crystal substrate, the second Si single crystal substrate is anisotropically etched. The degree of freedom in processing is increased, and an optical fiber with better shape controllability and a surface emitting semiconductor laser or laser array are combined.
The active layer of the surface emitting semiconductor laser is a III-V mixed crystal semiconductor containing N and other V groups. In the III-V mixed crystal semiconductor containing N and other V groups, the conduction band level is lowered at a rate of about 150 meV per 1% of N added in the region where the N concentration is low.
For this reason, for example, in a quantum well active layer composed of a combination with GaAs, the band gap discontinuity in the conduction band is large, and it is easy to adopt a configuration in which carrier overflow does not easily occur. It is possible to obtain a light emitting module using a surface emitting semiconductor laser that emits light at a wavelength of 1 and excellent in temperature characteristics.
The collimating or condensing lens has a structure that can be kept at a fixed distance from the surface emitting semiconductor laser element when it is attached, so that it can be aligned more accurately and at a low cost. A high-performance light emitting module can be obtained.
The optical fiber to be coupled is a single mode fiber. By using a single mode fiber, there is no optical mode dispersion even in high frequency optical transmission, and loss can be reduced. In addition, a high-performance light-emitting module with high accuracy and low cost can be obtained.

FIG. 11 is a top view showing a modification of the embodiment of the light emitting module according to the present invention. 12 is a side view of a modification of the light emitting module of FIG. This modification basically has the same configuration as the above-described embodiment.
However, at the same time, a concave portion 9a is formed on the substrate surface on the microlens side so as to be attached at a certain distance from the surface of the surface-emitting type semiconductor laser device 1, and the concave portion 13 and the convex portion 14 for alignment are connected to the silicon substrate 9 side. It is arranged on the surface emitting semiconductor laser substrate 6 side so that accurate alignment is possible (FIG. 12).
The concave portions 9a and 13 on the microlens 5 side can be easily formed having an opening of the order of about 100 μm using Si anisotropic etching. Since the substrate on the microlens side is obtained by directly bonding the Si (100) wafer to the inclined substrate that forms the reflecting prism 3 and the guide V-groove portion, the shape control is relatively easy.
The convex portion 14 on the semiconductor laser element substrate 6 side can also be formed in a mesa shape with an etchant having a certain degree of anisotropy (for example, a mixture of sulfuric acid and hydrogen peroxide solution diluted).

FIG. 13 is a schematic diagram for explaining a patterning process of a convex mesa shape. As a method, first, SiO ₂ or the like is formed as a protective film on a substrate on which a laser structure has been grown, and patterning of a convex mesa shape is performed using a photolithograph.
FIG. 14 is a schematic view for explaining a mesa shape forming process. FIG. 15 is a schematic view for explaining processing from the mesa shape forming step of FIG. 14 to the mesa shape. If etching is then performed with an etchant, a mesa shape as a convex portion is formed (FIG. 14).
After the formation is completed, the laser element portion is further processed into a mesa shape by etching (FIG. 15), and then a surface emitting semiconductor laser can be manufactured by a normal process. By using such a process, it is possible to form a structure having a somewhat large mesa-like protrusion at a portion outside the element portion of the semiconductor laser.
By designing the microlens side and the semiconductor laser substrate side so as to match each other, the semiconductor laser substrate 6 and the microlens 5 can be easily aligned using the concave portion 13 and the convex portion 14 as a guide. Become. Therefore, with the configuration of this embodiment, the manufacturing cost can be reduced, and an inexpensive and high-performance optical module can be achieved.

FIG. 16 is a schematic diagram illustrating an optical communication module using a light emitting module according to the present invention. In FIG. 16, the optical communication module is configured by a combination of the light emitting module A and the light receiving element 15 according to the embodiment of the present invention described above.
Therefore, since this optical transceiver module comprises an optical communication module using an inexpensive, small, and high-performance light emitting module, a cheaper, smaller, and higher-performance optical communication module can be obtained.
FIG. 17 is a schematic diagram showing an optical communication system using an optical transceiver module. In FIG. 17, by using the optical communication module of FIG. 16, the optical communication system can be more suitably configured by using an inexpensive, small, and high performance optical communication module.
FIG. 17 shows an optical communication system using the above-described optical communication module. The optical communication module of FIG. 16 is an optical communication module that is mounted at high density and can perform transmission in parallel. Therefore, in addition to the case of one-to-one optical communication, signals are paralleled to a plurality of different communication points. Can be sent to. Such an optical communication system can be more suitably configured by using an inexpensive, small, and high-performance optical communication module.

It is a top view which shows embodiment of the light emitting module by this invention. It is a side view of the light emitting module of FIG. It is a top view which shows the formation method of the reflective prism using Si single crystal substrate. FIG. 4 is a side view of FIG. 3. It is a top view which shows formation of the groove | channel for a guide of an optical fiber. FIG. 6 is a side view of FIG. 5. It is a top view which shows formation of the groove | channel for a guide of an optical fiber. FIG. 8 is a side view of FIG. 7. It is the schematic explaining the position alignment with the micro lens side and the reflective prism side. It is the schematic explaining alignment with the microlens formed in the back surface of the same Si single crystal substrate, and a reflective prism. It is a top view which shows the modification of embodiment of the light emitting module by this invention. It is a side view of FIG. It is the schematic explaining the patterning process of a convex part mesa shape. It is the schematic explaining the formation process of a mesa shape. It is the schematic explaining the process from the formation process of a mesa shape of FIG. 14 to a mesa shape. It is the schematic explaining the optical communication module which uses the light emitting module by this invention. It is the schematic which shows the optical communication system which uses an optical communication module.

Explanation of symbols

A Light emitting module 1 Surface emitting semiconductor laser (laser light emitting element)
2 Optical fiber 3 Reflecting prism 4 V-groove structure for optical fiber guide (V-groove part)
5 Micro lens (collimator or condenser lens)
6 Laser light emitting element substrate 9 Si single crystal substrate 15 Light receiving element 16 Optical communication module

Claims (10)

  In a light emitting module that couples a light emitting element of a surface emitting semiconductor laser having an oscillation wavelength of 1.1 μm or more and an optical fiber, the light emitting module is formed by processing a Si single crystal and is perpendicular to the surface emitting semiconductor laser element. A microlens that collimates or condenses the emitted light into parallel light, and a reflection that uses a Si (111) surface formed by processing a Si single crystal to bend the collimated or condensed light by approximately 90 °. A prism and a V-groove structure for an optical fiber guide formed with a Si (111) surface, and the microlens, the reflection prism, and the V-groove structure for an optical fiber guide are integrally formed. A light emitting module characterized by comprising:   In a light emitting module for coupling each light emitting element of a surface emitting semiconductor laser array having an oscillation wavelength of 1.1 μm or more and an optical fiber, each of the surface emitting semiconductor laser arrays is formed by processing a Si single crystal. A microlens array that collimates or condenses light emitted in the vertical direction of the light emitting element into parallel light, and Si (111) formed by processing a Si single crystal to bend the collimated or condensed light by approximately 90 ° A reflecting prism having a reflecting surface and an optical fiber guide V-groove structure formed of a Si (111) surface, and the microlens, the reflecting prism, and the guide V-groove structure are integrally formed. A light emitting module characterized by being formed.   The microlens, the reflecting prism, and the guide V-groove structure are integrally formed on the same Si single crystal substrate having a surface inclined 9.7 ° from the (100) plane in the <110> direction. The light-emitting module according to claim 1 or 2.   A step of preparing a first Si single crystal substrate having a surface inclined 9.7 ° from the (100) plane in the <110> direction; a step of preparing a second Si single crystal substrate; A step of bonding the two Si single crystal substrates, a step of forming a reflecting prism and a guide V-groove structure on the bonded first Si single crystal substrate surface side, and a bonded second Si single crystal substrate surface side And a step of forming a microlens.   5. The light emitting module manufactured using the manufacturing method according to claim 4, wherein the second Si single crystal substrate has a crystal orientation different from that of the first Si single crystal substrate.   6. The light emitting module according to claim 1, wherein an active layer of the surface emitting semiconductor laser is a III-V mixed crystal semiconductor containing N and other V groups. .   5. The space maintaining structure for maintaining a distance between the microlens and the surface-emitting type semiconductor laser element as a single unit according to claim 1, wherein the distance maintaining structure is integrated. The light emitting module according to any one of claims 1 to 3 and claims 5 to 6.   The light emitting module according to any one of claims 1 to 3, or 5 to 7, wherein the optical fiber to be coupled is a single mode fiber.   An optical transceiver module using the light emitting module according to any one of claims 1 to 3 or claims 5 to 7.   An optical communication system using the optical transceiver module according to claim 9.

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