JPH0784162A - Optical element mounting structure and its mounting method - Google Patents

Abstract

(57) [Abstract] [Purpose] A high-density mounting of optical elements having a plurality of stacked input / output terminals and an optical fiber matrix can be performed by automatic alignment to reduce the mounting area and solve the problems of optical fiber congestion. It is to realize a novel optical element mounting structure and its mounting method. [Structure] An optical unit 18 in which an optical element 6 having a plurality of input / output terminals is face-down bonded to a submount 5 is vertically laminated as a unit, and a fiber guide 2 serving as a positioning substrate for the laminated optical element. Is used to connect the optical fiber matrices 1 arranged in a matrix. A hole 12 for fixing a fiber and a hole 11 for a guide pin are opened in the fiber guide 2, and the optical fiber array 1 and the guide pin 3 are inserted into these, and the guide pin 3 is aligned with the guide groove 10 formed in the optical switch, and the X axis, Automatically adjust in the Y-axis direction. In the Z-axis direction, an appropriate spacer 4 is used between the fiber guide 2 and the optical element 6 for alignment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element mounting structure for stacking a plurality of optical elements at predetermined intervals in multiple layers and connecting and fixing an optical fiber array to the input / output ends of the stacked optical elements. More particularly, the present invention relates to a mounting structure of an optical element suitable for mounting the optical element and the optical fiber at a high density and automatically aligned with each other, and a mounting method thereof.

[0002]

2. Description of the Related Art As Conventional Example 1, for mounting an optical element array having a plurality of input / output terminals, see, for example, Optical Engineering Vol. 29, No. 3, pp. 191-199, 1990 [OPTICAL ENGINEERING, vol. No.3, p.191-199 (199
0)]. That is, a method of positioning a front spherical fiber to be connected with a V groove prepared in advance on a Si substrate and coupling it to an optical waveguide of an optical element with a fiber connecting device having a through hole having a pyramidal structure is described on page 192-2.
Explained in Section 2.

Further, as a conventional example 2, Japanese Patent Application Laid-Open No. 5-590.
As disclosed in Japanese Patent No. 8, there is an optical switch in which a large-scale matrix switch can be made compact.
That is, in this optical switch, each optical coupling element is laminated and fixed with an adhesive, and the two laminated optical units are opposed to each other so that the laminating directions thereof are orthogonal to each other. They are arranged so as to coincide with each other, and are fixed by adhesion in an optically connected state.

[0004]

The technique of the above-mentioned conventional example 1 discusses the connection between the optical element array having a plurality of input / output terminals on a single plane and the optical fiber array, but the array scale of the element is expanded. Then, the mounting area becomes large in plan view. In addition, the number of optical fiber arrays expands in a plane, which causes a problem of congestion when mounting optical fibers. Further, no consideration is given to stacking the optical element arrays to increase the density.

Further, in the second conventional example, a method of constructing a large-scale optical switch in which optical coupling elements are laminated and fixed with an adhesive and multiplexed is described. Regarding the connection relationship between two laminated optical units. It is a proposal and does not describe any connection mounting relationship between an optical coupling element having a plurality of stacked input / output terminals and an optical fiber. In this type of high-density mounting technology, how to precisely connect an optical fiber to the input and output ends of the optical elements together with the lamination of the optical elements is a very important practical issue.

Therefore, an object of the present invention is to solve such a problem. Specifically, it is possible to easily perform high-density mounting by automatic alignment between an optical element having a plurality of stacked input / output terminals and an optical fiber matrix. (EN) Provided is a novel optical element mounting structure and a mounting method thereof. As a result, the positioning of the optical component can be performed accurately and easily, the mounting area can be reduced, and the problems of optical fiber congestion can be solved.

[0007]

The above object is to provide an optical element in which an optical waveguide forming at least an input / output end and a plurality of guide grooves for positioning are provided at both ends of the optical substrate in an optical substrate, and a predetermined optical element. An optical element having a pair of flat plate-shaped fiber guides provided with positioning holes and an optical fiber matrix in which each optical fiber end is optically coupled to and fixedly connected to a fiber fixing hole provided in the fiber guide. In the mounting structure, the optical elements are multi-layered between the pair of flat plate-shaped fiber guides, and the stacked optical elements are passed through predetermined positioning holes provided in the fiber guide. This is achieved by an optical element mounting structure that is positioned and fixed at a predetermined position by a guide pin that is inserted through the guide groove. Further, an optical element having at least an input / output end in the optical substrate, an optical switch mechanism operated by electro-optical means on the optical waveguide, and a plurality of positioning guide grooves are provided to an optical element and a power supply terminal. This is achieved by an optical element mounting structure in which an optical unit formed by electrically connecting and fixing a submount including the above is laminated between a pair of flat plate-shaped fiber guides.

Further, the above-mentioned object is to prepare an optical element having at least an optical waveguide forming an input / output end in an optical substrate and a plurality of guide grooves for positioning at both ends of the substrate. A plurality of optical elements are sequentially laminated and sandwiched between a pair of flat plate-shaped fiber guides, and guide pins are inserted into the guide grooves of the optical elements through positioning holes that are provided at predetermined positions of the fiber guides to position and fix them. And a step of inserting and fixing each optical fiber end of the optical fiber matrix into a fiber fixing hole provided in the fiber guide to obtain optical coupling between the input / output end of the optical element and the optical fiber matrix. It is also achieved by the mounting method of the optical element.

As an optical element, an optical waveguide forming at least an input / output terminal is formed on a predetermined optical substrate by a known method. Depending on the application, an optical demultiplexer, an optical multiplexer,
It also has an optical switch. When an optical switch is provided, an electrode for inputting an electric signal that constitutes a part of the optical switch mechanism is provided at the intersection of the optical waveguides. Then, in this case, a submount having a power supply terminal for inputting an electric signal to the electrode from the outside is mounted on the optical element.

When mounting an optical element also provided with such an optical switch, the object is achieved by the following mounting method. That is, an optical element having at least an input / output terminal in the optical substrate, an optical switch mechanism operated on the optical waveguide by electro-optical means, and a plurality of guide grooves for positioning are connected to a power supply terminal. A step of electrically connecting and fixing a submount equipped with the optical unit to assemble the optical unit, and a plurality of optical units are sequentially laminated and sandwiched between one set of flat plate-shaped fiber guides at a predetermined interval, and at a predetermined position of the fiber guide. Inserting and fixing the guide pin into the guide groove of the optical unit by positioning it through the positioning hole that is provided in advance, and inserting and fixing each optical fiber end of the optical fiber matrix into the fiber fixing hole provided in the fiber guide. Then, it is achieved by a method of mounting an optical element, which comprises a step of taking an optical coupling between the input / output end of the optical element and the optical fiber matrix. As a method for electrically connecting and fixing the submount provided with the power supply terminal to the optical element, for example, the electrode of the optical element and the power supply terminal of the submount are connected and fixed by connecting means such as face-down bonding. In order to facilitate the stacking and positioning of the optical units, it is desirable to dispose a guide groove of the same shape on the submount side facing the guide groove of the optical element.

After stacking optical elements and optical units between the fiber guides and positioning them with guide pins, before connecting the optical fibers, in order to prevent misalignment, for example, an adhesive is injected to guide the guides. It is desirable to take a fixing means such as fixing the pin to a fiber guide, a guide groove of an optical element or an optical unit.

Further, when inserting and fixing each optical fiber end of the optical fiber matrix into the fiber fixing hole provided in the fiber guide, in order to facilitate optical coupling between the fiber end and the input / output end of the optical element, If necessary, for example, a spacer or lens having a predetermined thickness may be preliminarily interposed between the optical element and the fiber guide, and an optical coupling means may be provided for adjusting the focal point of the front spherical fiber to the input / output end of the optical element.
For example, when using a flat lens for optical coupling of the fiber, place an appropriate transparent plate between the lens and the fiber, or between the lens and the optical element to focus the lens and fix the fiber in correspondence with the lens. Just align them.

In addition, the structure of the submount will be additionally described. The submount includes a power supply terminal for connecting to an electrode for driving an optical switch, which is provided on one surface of an optical element having a plurality of input / output terminals, and a wiring connected thereto. Through this wiring terminal, it can be connected to an external optical switch control system.
The material of the submount is a dielectric having excellent thermal conductivity and a thermal expansion coefficient close to that of the substrate material forming the optical element, such as silicon carbide SiC or aluminum nitride AlN.

Further, since the fiber guide plays a role of a positioning substrate for various optical components at the time of mounting, it may be made of a material that has a certain degree of rigidity and is easy to process such as drilling. For example, a silicon substrate. A quartz substrate is used. The structure of the guide focus and the hole for inserting the optical fiber provided therein can have a desired polygonal cross-sectional shape including a circle. A preferable structure of the hole for fixing the fiber is, for example, a through hole having a conical pyramidal structure. Further, a plurality of holes for guiding the guide pins and determining the stacking position of the optical element are provided separately from each other for each optical element to be stacked similarly to the fiber fixing hole. It is installed near both corners.

Further, the guide pin has a cross-sectional shape adapted to the shape of the guide groove of the optical element so as to prevent unnecessary slack between the grooves. When using the submount, guide grooves are formed on both sides, and guide pins are inserted between them to enable stable positioning. The material of the guide pin may be any material as long as it has a certain degree of rigidity, and may be a metal or a dielectric.

[0016]

The fiber guide serves as a laminated positioning substrate for the optical element during mounting, and as a positioning and fixing substrate that is laminated and surely couples the optical fibers to the input / output ends of each optical element end face. Therefore, in the fiber guide, holes for inserting guide pins for stacking positioning corresponding to a predetermined interval of each optical element to be stacked, and optical fiber positioning fixing fixed to the pitch of the input and output ends of each optical element end face are fixed. There is a hole for.

That is, by forming guide grooves for aligning the guide pins in the optical element having a plurality of input / output ends and the submount by the same lithographic technique and etching technique as in the optical element production, mutual positioning in stacking is performed. The accuracy is high. Also, the holes of the fiber guide can be manufactured with an accuracy of several μm even by lithographic techniques or machining, and the positions of the fibers and the positions of the optical element in the lateral direction and the vertical direction can be simultaneously increased. It can be decided with accuracy, and high-density mounting becomes possible.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 schematically shows a perspective view of a main part in a state where mounting of an optical element is completed. In this embodiment, an example will be described in which an optical switch is used as an optical element having a plurality of input / output ends on both end faces. First, the outline of the mounting method will be described with reference to this figure.
Four units of a single layer obtained by face-down bonding the optical switch chip 6 of 4) to the submount 5 were vertically laminated. An optical fiber matrix 1 arranged in a matrix of 4 rows and 4 columns was connected to this laminated optical element using a fiber guide 2. In order to optically connect the waveguide element and the optical fiber, the positions in the XYZ3 directions shown in the figure must be adjusted at the same time. The guide pin 3 is used to align the positions of the optical switch 6 and the optical fiber array 1 in the X-axis and Y-axis directions. The spacer 4 was used for the alignment in the Z-axis direction.

FIG. 2 is a top view showing a positioning structure of the optical switch 6 and the fiber guide 5 corresponding to one layer of FIG. The optical switch 6 includes an input / output optical waveguide 7 provided in an optical substrate and an electrode 8 provided on an optical waveguide that intersects with each other.
A well-known configuration including (only one intersection is shown in the figure, other intersections are omitted) and a switch section in which the waveguide is switched by an electro-optical mechanism when an electric signal is applied to the common electrode 9. The structure in which the P-side electrode 8 and the N-side electrode 9 are taken out on the same surface, and the electrode wiring is taken out by face-down bonding of only one surface with the electrode (not shown) of the submount 5 having a power supply terminal. It has a structure that allows The electrodes 8 and 9 on the optical switch were taken out by the electrodes patterned on the submount 5 and were connected to the electrodes of the case that accommodates the whole and taken out to the outside.

Positioning of the optical switch 6 and the fiber guide 2 is performed by a guide pin 3, and a guide groove 10 penetrating from one end to the other end is used as a guide for alignment on the optical switch side of the optical element substrate 6 by using lithography and etching techniques. Formed on both sides. Since the precision of the guide groove 10 can be the same as that of the optical waveguide 7, the relative position of the fiber guide 2 and the optical switch 6 can be determined in μm unit.

FIG. 3 shows the fiber guide 2 used in FIG.
In a plan view showing an example, the relative position of the guide pin 3 and the optical fiber array 1 was determined by inserting the guide pin 3 into the guide pin positioning hole 11 and the optical fiber array 1 into the fiber fixing hole 12.

The assembling procedure for obtaining the mounted state of FIG. 1 will be described more specifically as follows. (A) The submount 5 is mounted on the optical switch 6, both electrodes are connected and fixed by face-down bonding, and four sets of optical units 18 are prepared. (B) A pair of left and right fiber guides 2 is used as a positioning substrate, the optical unit 18 assembled in (a) is sandwiched between them, and the guide pin 3 is inserted from the positioning hole 11 of one fiber guide 2 to the guide groove of the optical unit 18. It penetrates 10 and is inserted in the hole of the other fiber guide 2. This process is repeated three times to stack and position the four-layer optical unit 18. The optical unit 1 is placed between the pair of fiber guides 2.
When sandwiching 8 and positioning with the guide pin 3, a spacer 4 of a predetermined thickness for adjusting the focal length is provided between the fiber guide 2 and the end surface of the optical unit 18 to facilitate the optical coupling state when the optical fiber is connected. Insert as necessary. The X-axis and Y-axis two-dimensional positioning of the laminated optical units 18 at this stage is performed by a pair of left and right fiber guides 2 and guide pins 3, and the input and output ends of each laminated optical unit 18 are , The fiber guide 2 is correctly positioned so as to face the fixing hole. On the other hand, the Z-axis alignment between the fiber guide 2 to which the optical fiber array is fixed and the input / output ends of each optical unit 18 is performed by appropriately selecting the thickness of the spacer 4. (C) Next, each optical unit 1 is guided by the fiber guide 2.
When the optical components 8 are correctly positioned, the optical unit 18 and the hole 11 of the fiber guide 2 where the guide pins 3 contact the adhesive, for example, so that these optical components do not become displaced.
Fix it by pouring it into the guide groove. (D) Finally, attach the optical fiber array 1 to the fiber guide 2
It is inserted and fixed in the fiber fixing hole 12.

<Embodiment 2> FIG. 4 shows another structural example of the fiber guide 2 and an example in which the optical switches 6 as optical elements are directly laminated without mounting the submount 5 on the optical switch 6. Is. FIG. 3A is a plan view in which a flat plate lens 13 is embedded in a portion corresponding to the fiber fixing hole 12 of the fiber guide 2 shown in FIG. 3, and the fiber fixing hole 12 is provided with a transparent plate 14 as a separate body. It is a figure, and the figure (b) shows the front view of the important section in the mounting state.
As shown in FIG. 3B, the transparent plates 14a and 14b for adjusting the focal length of the flat lens 13 are provided between the optical fiber 1 and the fiber guide 2 and between the fiber guide 2 and the optical switch 6.
By sandwiching and fixing between them, the positions of the optical fiber array 1 and the optical switch 6 in the Z-axis direction were determined. Transparent plate 14
The guide pins 3a and 14b are the same as the fiber guide 2
The positioning hole 11 is formed, the guide pin 3 is inserted, and the optical fiber array 1 and the optical switch 6 are aligned in the X-axis and Y-axis directions. In addition, a fiber fixing hole 12 (not shown) is provided in the transparent plate 14a so as to correspond to the flat plate lens 13 of the fiber guide 2. This implementation example
Unlike the case of the first embodiment, since the submount 5 is not mounted on the optical switch 6, it is possible to reduce the stacking area and is suitable for high-density mounting. However, since the submount 5 is not used, electrode extraction of the optical switch is performed. Requires a means for taking out directly from the switch substrate.

<Embodiment 3> In the above two embodiments, the case where four optical switches 6 are laminated has been described as a representative example. However, in general, an optical element having a plurality of input / output terminals and an optical fiber matrix are mounted. It goes without saying that it can be applied. FIG. 5 shows an example in which a plurality of optical elements, which are laminated in a desired number of layers, are optically coupled to each other through an optical fiber matrix.

FIG. 5A is a block diagram of a generally known three-stage cross network. The first stage has r optical switches whose input and output terminals are n × m, and the second stage has r × r optical switches, and the third stage has m × n optical switches. By combining them, an N × N (N = n · r) optical switch matrix can be constructed. However, when the optical switch 6 is arranged on a plane as shown in this figure, there arise problems of fiber congestion due to interconnection and an increase in mounting area.

Such an optical switch matrix structure is
This can be embodied in the schematic diagram shown in FIG. Figure 5
FIG. 5C shows FIG. 5B in units of the optical module, the optical fiber matrix, and the fiber guide 2 for positioning and mounting them, and four fiber matrices 15 and 1 are provided.
It is shown that it is easily constituted by 6 and 3 optical modules 17 and the fiber guide 2 connecting them, and the problems of fiber congestion and mounting area are solved.

Using the mounting method shown in the first embodiment, r optical switches 6 having n × m input / output terminals are stacked in the first stage, and r × r optical switches 6 are similarly used in the second stage. M layers are laminated, and r optical switches 6 of n × m are similarly laminated in the third stage, and adjacent optical modules 17 are optically coupled via the fiber guide 2 and the optical fiber matrix 15. As shown in the figure, adjacent optical modules 17 are arranged rotated by 90 degrees, and the optical fiber matrix 15 of r rows and m columns is fixed and coupled to the fiber guide 2. The optical fiber matrix 16 of r rows and n columns is fixed and coupled to the fiber guide 2 at both input and output ends. In this case, the optical fiber matrix 1
5 may be replaced with the flat lens 13 of FIG. Further, although the example in which the optical module 17 is rotated by 90 degrees is shown in this example, it is said that the same configuration can be obtained by rotating the optical fiber matrix 15 by 90 degrees by utilizing the flexibility of the optical fiber matrix 15. There is no end.

[0028]

As described above in detail, according to the present invention, the intended purpose can be achieved. That is, the optical fiber and the laminated optical element can be automatically aligned with each other by using the fiber guide serving as the positioning substrate, and the mounting area can be reduced to achieve high-density mounting. Also, the problem of congestion when mounting an optical fiber is solved.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part showing a mounted state of an optical element according to an example (Example 1) of the present invention.

FIG. 2 is a top view showing a connection state between the optical switch and the optical fiber array.

FIG. 3 is a plan view showing one structural example of the fiber guide.

FIG. 4 is an explanatory view of a case where a flat lens is used for a fiber guide which is another embodiment (Example 2).

FIG. 5 shows another embodiment (embodiment 3) in which an optical module in which a plurality of optical elements are stacked and a plurality of optical fiber matrices are positioned and fixed via fiber guides, respectively.
Explanatory diagram showing an implementation example.

[Explanation of symbols]

1 ... Optical fiber array, 2 ... Fiber guide,
3 ... Guide pin, 4 ... Spacer,
5 ... Submount, 6 ... Optical switch, 7 ... Optical waveguide, 8 ... P electrode, 9 ... N
Electrode, 10 ... Guide groove, 11 ... Guide pin positioning hole, 12 ... Fiber fixing hole, 13
... Plane lens, 14 ... Transparent plate, 15 ... Optical fiber matrix of r rows and m columns, 16 ... Optical fiber matrix of r rows and n columns, 17 ... Optical module, 18 ... Optical unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Kato 1-280, Higashi Koigokubo, Kokubunji, Tokyo Metropolitan Research Center, Hitachi, Ltd.

Claims (10)

[Claims] 1. An optical element having at least an optical waveguide forming an input / output end in an optical substrate, a plurality of positioning guide grooves provided at both ends of the substrate, and a set of predetermined positioning holes. A flat plate-shaped fiber guide, and an optical element mounting structure comprising an optical fiber matrix in which each optical fiber end is optically coupled and fixedly connected to a fiber fixing hole provided in the fiber guide, An optical element is multiply laminated between the pair of flat plate-shaped fiber guides, and each laminated optical element is inserted into a guide groove of each optical element through a predetermined positioning hole provided in the fiber guide. A mounting structure for an optical element, which is positioned and fixed at a predetermined position by a pin. 2. An optical element having an optical waveguide that forms at least an input / output end in an optical substrate, an optical switch mechanism that operates on the optical waveguide by electro-optical means, and a plurality of guide grooves for positioning. 2. The mounting structure for an optical element according to claim 1, wherein an optical unit formed by electrically connecting and fixing a submount provided with a power supply terminal is multi-laminated between a pair of flat plate-shaped fiber guides. 3. A step of preparing an optical element in which an optical waveguide forming at least an input / output end in an optical substrate and a plurality of guide grooves for positioning are provided at both ends of the substrate, and a set of flat plates. A plurality of optical elements are sequentially laminated and sandwiched between the fiber guides, and a guide pin is inserted into a guide groove of the optical element through a positioning hole previously provided at a predetermined position of the fiber guide to position and fix the fiber. Mounting an optical element comprising inserting and fixing each optical fiber end of the optical fiber matrix into a fiber fixing hole provided in the guide, and optically coupling the input / output end of the optical element and the optical fiber matrix. Law. 4. An optical element comprising an optical waveguide which constitutes an input / output terminal on a predetermined optical substrate, and at least one selected from the group consisting of an optical demultiplexer, an optical multiplexer and an optical switch. Item 3. The optical element mounting method according to Item 3. 5. An optical device having an optical waveguide that forms at least an input / output end in an optical substrate, an optical switch mechanism that operates on the optical waveguide by electro-optical means, and a plurality of guide grooves for positioning. , A step of electrically connecting and fixing a submount equipped with a power supply terminal to assemble an optical unit, and sequentially stacking and sandwiching a plurality of optical units between a set of flat plate-shaped fiber guides at a predetermined interval, and Inserting the guide pin into the guide groove of the optical unit through the positioning hole previously provided at the predetermined position of the optical unit and positioning and fixing, and the optical fiber end of each optical fiber matrix in the fiber fixing hole provided in the fiber guide. And fixing the optical element to obtain an optical coupling between the input and output ends of the optical element and the optical fiber matrix. 6. The method according to claim 3, further comprising the step of interposing a spacer for adjusting optical coupling between the optical element and the fiber guide to mutually position the input / output end of the optical element and the fiber array. Any one of the optical element mounting methods. 7. A flat lens is used for optical coupling of the fiber,
A method comprising the steps of sandwiching a transparent plate having a predetermined thickness between the lens and the fiber and between the lens and the optical element, focusing the lens, and fixing and aligning the fiber corresponding to the lens. 6. The optical element mounting method according to any one of 3 to 5. 8. An optical device comprising a set of fiber guides, the fibers of which are arranged on one surface of a plurality of optical fiber arrays in a matrix, and the other surface of which is provided with at least an optical switch having a plurality of inputs and a plurality of outputs. Sub-mounts that are stacked in layers with each optical element at the stage of stacking and fixing multiple layers of the optical elements, extracting the electrodes for driving the optical switch from the surface of each optical element, and electrically connecting them to the power supply terminals of the submount Is positioned by inserting and fixing a guide focus in the guide groove provided in the submount through the positioning hole provided in the fiber guide, and the optical element and the optical fiber array are optically connected and the optical element The electrodes are connected and fixed by face-down bonding with the submount, and are connected to the fiber guide via the wiring of the submount. Mounting method of the optical device of claims 3 to 7, wherein one comprising a step of pulling out the that direction. 9. An optical module in which r × n optical switches having n × m input / output terminals are laminated, an optical module in which m × p optical switches having r × r optical input / output terminals are laminated, and m When optically coupling an optical module in which r layers of × n optical switches are laminated with a fiber matrix of r rows and m columns, positioning of each input / output end of the optical module and each fiber of the fiber matrix optically coupled thereto is claimed. Item 9. An optical element mounting method for forming a multi-stage cross network, comprising the steps of automatic alignment in the optical element mounting method according to any one of items 3 to 8. 10. The method according to claim 9, further comprising the step of arranging adjacent optical modules rotated by 90 degrees with respect to each other and automatically aligning and optically coupling to a fiber matrix of r rows and m columns through a fiber guide. Method of optical device for multi-stage cross-network of the above.