JP2003121767A - Optical switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical switch which reduce its insertion loss of light by fixing a projection-side optical fiber and an incidence-side optical fiber receiving light reflected by a mirror to a substrate so that they have a height difference. SOLUTION: The optical switch is equipped with a fixed electrode substrate 8, a substrate 1, a movable electrode plate 2 which is fitted to and coupled with the substrate 1 across a flexure 21, mirrors 31 and 32 which are formed on the surface of the movable electrode plate 2, and the projection-side optical fiber 4 and incidence-side optical fiber 5 which are arrayed individually on the substrate 1 along a parallel straight line; and the mirrors 31 and 32 are positioned opposite the projection-side optical fiber 4 and incidence-side optical fiber 5 and light is switched and controlled by electrostatically driving the movable electrode plate 2. The projection-side optical fiber 4 and incidence-side optical fiber 5 which receives light reflected by the mirrors are fixed to the substrate 1 not in level with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical switch, and more particularly, to an optical switch in which an emitting side optical fiber and an incident side optical fiber for receiving reflected light from a mirror are fixed to a substrate 1 with a height difference.

[0002]

2. Description of the Related Art A prior art example of a 2 × 2 optical switch in which four mirrors are formed on the surface of a movable electrode plate and the direction of light emitted from an output side optical fiber is switched and transmitted to an input side optical fiber. This will be described with reference to FIG. FIG. 5 is a diagram for explaining the assembled 2 × 2 optical switch. 2 in FIG.
A view of the × 2 optical switch as seen from above, and FIG.
It is a figure which shows the longitudinal cross section which passes along the axial center of the entrance side optical fiber 5 and the exit side optical fiber 4'in (a).

Microlenses 91 and 92 constitute a microlens array 9 by cutting out two adjacent microlenses from a flat plate microlens array in which a large number of lens portions are arranged in a matrix on a transparent flat plate.
The optical fiber 4 on the emission side is disposed so as to face the microlens 91 of the microlens array 9.
An incident-side optical fiber 5 is arranged opposite to the optical fiber 2. Similarly, the micro lens 91 'of the micro lens array 9'
The exit side optical fiber 4'is arranged so as to face each other, and the incidence side optical fiber 5'is arranged so as to face the microlens 92 '.

This 2 × 2 optical switch has two output side optical fibers 4, 4'and two input side optical fibers 5,
5'of four optical fibers, and four microlenses 91, 92, 9 arranged facing these optical fibers
1 ', 92', a movable electrode plate 2, mirrors 31, 32, 31 ', 32' formed on the movable electrode plate 2, and a fixed electrode substrate 8 bonded and fixed to the movable electrode plate 2. Movable electrode plate 2
Are bonded and held to the substrate 1 via the flexure portion 21. In these optical fibers, one outgoing side optical fiber 4 and one incoming side optical fiber 5'are arranged so as to face one of the two parallel straight lines, and the other straight line has one. The exit side optical fiber 4'and one entrance side optical fiber 5 are arranged so as to face each other. Then, between the outgoing side optical fiber 4 and the incoming side optical fiber 5 ', and between the facing side outgoing side optical fiber 4'and the incoming side optical fiber 5'.
A mirror formed on the movable electrode plate 2 is arranged between the two, facing the optical fiber. Further, respective condenser microlenses are arranged immediately in front of each of the outgoing side optical fibers 4 and 4'and the incoming side optical fibers 5 and 5 '. A mirror formed on the movable electrode plate 2 is positioned between the lenses.

The switching operation of the 2 × 2 optical switch will be described with reference to FIG. In this 2 × 2 optical switch, in the steady state shown in FIGS. 6A and 6B, the light incident through the emission side optical fiber 4 is reflected by the mirror 31.
The light is reflected by the mirror 32 and is incident on the incident side optical fiber 5, but is blocked by the mirror 31 and is not incident on the other incident side optical fiber 5 '. On the other hand, the light entering through the exit side optical fiber 4'is reflected by the mirrors 31 'and 32' and enters the entrance side optical fiber 5 ', but is blocked by the mirror 31' and enters the entrance side optical fiber 5. Does not enter. A voltage is applied between the movable electrode plate 2 and the fixed electrode substrate 8 to attract the movable electrode plate 2 downward.
In the driving state of (c) and FIG. 6 (d), the light incident through the emission side optical fiber 4 travels straight above the mirror 31 and the mirror 32 'and passes through the incidence side optical fiber 5'.
But does not enter the incident-side optical fiber 5. On the other hand, the light that enters through the output-side optical fiber 4 ′ travels straight above the mirrors 31 ′ and 32 and enters the entrance-side optical fiber 5, but does not enter the entrance-side optical fiber 5 ′. 2x2 optical switch is as above,
It is possible to switch the direction of the light emitted from the emission side optical fibers 4, 4'and transmit it to the incidence side optical fibers 5, 5 '.

Here, a mirror 3 is provided on the upper surface of the movable electrode plate 2.
A method of constructing 1, 32, 31 ', 32' will be described with reference to FIG. Referring to FIG. 7A, a photosensitive synthetic resin E having a thickness of several tens of μm is applied to the entire surface of the substrate 1. Figure 7
Referring to (b), the photosensitive synthetic resin E mirror 31,
The mirror shape m is constructed by exposing L from above only where 32, 31 ', 32' are to be formed by vertical hatching.

Referring to FIG. 7C, the photosensitive synthetic resin E in a portion which is not exposed by developing is removed. Figure 7 (d)
For example, by coating the mirror shape m with a metal, the mirrors 31, 32, 3 having a height of several 100 μm can be obtained.
1 ', 32' are formed (for details of the above, refer to Japanese Patent Application No. 2000-270621 related to the application by the applicant).

[0008]

Problems to be Solved by the Invention Mirrors 31, 32, 3
As described above, 1'and 32 'are formed by exposing and developing the photosensitive synthetic resin E formed on the surface of the substrate 1 which will be the movable electrode plate 2 later as a raw material. In this case,
Referring to (e), these mirror substrates m may not be formed so that the surfaces on the optical fiber side facing each other are completely perpendicular to the surface of the substrate 1, but may be formed slightly inclined. That is, the surface of the mirror substrate m tends to be formed so that its thickness gradually decreases as it approaches the substrate 1. This is mirrors 31 and 3 of photosensitive synthetic resin E having a thickness of several tens of μm.
It is considered that this is because an exposure gradient occurs in the thickness direction from the surface of the photosensitive synthetic resin E when the areas where 2, 31 ′ and 32 ′ are to be formed are exposed from above. Here, when the surface of the mirror base body m facing the optical fiber side is formed to be inclined at an acute angle or an obtuse angle when viewed from the surface of the substrate 1, the mirror 3 formed by coating with metal is formed.
The light incident on the surface of the optical fiber 1, 4 ′ through the output side optical fibers 4, 4 ′ and the respective lenses is reflected by the mirrors 31, 3 ′.
On the surface of 1 ', it will be reflected with a slight component in the height direction of the mirror. That is, when the mirror surface is formed to be inclined at an acute angle when viewed from the surface of the substrate 1, the incident light is reflected while being inclined slightly downward from the surface of the mirror. Therefore, when the exit side optical fibers 4, 4'and the entrance side optical fibers 5, 5'are positioned and fixed on a common plane, the optical axis of the reflected light and the entrance side optical fibers 5, 5'are aligned. The light is not parallel, and the reflected light has a height difference and is incident on the port on the incident side.
Proper incidence is not made on each of the 5'lenses, and eventually an insertion loss of light by the 2 × 2 optical switch occurs.

The present invention provides an optical switch that solves the above-mentioned problems by fixing the optical fiber on the outgoing side and the optical fiber on the incoming side that receives the reflected light from the mirror with a height difference and fixed to the substrate.

[0010]

According to a first aspect of the present invention, there is provided a fixed electrode substrate 8, a substrate 1, a movable electrode plate 2 attached and coupled to the substrate 1 via a flexure portion 21, and a mirror formed on the surface of the movable electrode plate 2. 31 and 32, and an emission side optical fiber 4 and an incidence side optical fiber 5 which are separately arranged on the substrate 1 along straight lines parallel to each other, and the mirrors 31 and 32 include the emission side optical fiber 4 and the incidence side optical fiber. In the optical switch that is positioned so as to face the movable electrode plate 5 and electrostatically drives the movable electrode plate 2 to control light switching, a height difference is provided between the light emitting side optical fiber 4 and the light incident side optical fiber 5 that receives the light reflected by the mirror. The optical switch fixed on the substrate 1 was constructed.

According to a second aspect of the present invention, in the optical switch according to the first aspect, the second incident side optical fiber 5 faces the emission side optical fiber 4 along a straight line on which the emission side optical fiber 4 is arranged. 'Is arranged to form an optical switch. Further, claim 3: the fixed electrode substrate 8, the substrate 1, the movable electrode plate 2 attached and coupled to the substrate 1 via the flexure portion 21, and the mirrors 31, 3 formed on the surface of the movable electrode plate 2.
2, 31 ', 32', emission side optical fibers 4, 4'arranged along both of the two straight lines parallel to each other, and incidence side arranged opposite to the emission side optical fibers 4, 4 ' Includes optical fibers 5, 5 ', mirrors 31, 32, 31', 3
2'is positioned between the output side optical fiber and the input side optical fiber so as to face these optical fibers, and in the optical switch for electrostatically driving the movable electrode plate 2 to control light switching, the output side optical fiber 4, The optical switch 4'and the incident side optical fibers 5 and 5'for receiving the reflected light from the mirror are fixed to the substrate 1 with a height difference.

Further, claim 4: claim 1 to claim 3
In the optical switch described in any of the above, a V-shaped groove 14 is separately formed in the substrate 1 along a straight line parallel to each other to position and fix the emission side optical fiber and the incidence side optical fiber. Then, a section V-shaped groove 14 for positioning and fixing the output side optical fibers 4 and 4'and a section V-shaped groove 1 for positioning and fixing the incident side optical fiber for receiving the reflected light by the mirror.
An optical switch was formed by forming 4 with different depths.
Further, in a fifth aspect of the optical switch according to any one of the first to fourth aspects, the mirror is formed by exposing and developing a photosensitive synthetic resin and coating the surface of the structure with a metal. Optical switch consisting of.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the examples of FIGS. 1 and 2 are views for explaining the manufacturing process of the substrate, the movable electrode plate, and the mirror. (Step 1) A substrate made of silicon is prepared as the substrate 1. (Step 2) A polycrystalline silicon film is formed on the surface of the substrate 1, and the connecting portion 211, the flexure portion 21, and the movable electrode plate 2 are formed.
Pattern in the shape of. (Step 3) The front surface and the back surface of the substrate 1 are covered with the silicon dioxide film 7 to form the shape required for forming the counterbore 12
Patterning is performed on the silicon dioxide film 7 on the back surface of the.

(Step 4) The back surface of the substrate 1 is etched to form the counterbore 12. (Step 5) The silicon dioxide film 7 on the surface of the substrate 1 is patterned into a shape required to form two lens mounting recesses 13 and two V-shaped cross-section grooves 14 extending in parallel from these. . Here, the width of the pattern of the V-shaped groove 14 in cross section is changed according to the depth of the V-shaped groove 14 in cross section to be formed. That is, the width of the pattern of the V-shaped groove 14 in cross section is increased in proportion to the depth of the V-shaped groove 14 in cross section.

(Step 6) The surface of the substrate 1 is etched to form the lens mounting recess 13 and the V-shaped groove 14 in cross section,
14 '. (Step 7) The silicon dioxide film 7 remaining in the step 6 is removed. (Step 8) A photosensitive synthetic resin E having a thickness of several tens of μm is applied to the entire surface of the substrate 1. (Step 9) Mirrors 31 and 3 in the photosensitive synthetic resin E
The mirror shape m is constructed by exposing L from above only where the 2, 31 ', 32' are to be formed by vertical hatching.

(Step 10) The photosensitive synthetic resin E which is not exposed by developing is removed. (Step 11) Mirrors 31, 32, 3 having a height of several tens of μm by coating the mirror shape with metal
1 ', 32' are formed. By the above (Step 1) to (Step 11), the substrate, the movable electrode plate and the mirror as shown in FIG. 3 were formed. (Step 12) Separately, a semiconductor substrate is used as a raw material substrate, and a peripheral portion is subjected to etching processing to form a central raised portion 81 and a flange portion 82 surrounding the central raised portion 81, and the fixed electrode substrate shown in FIG. 8 is manufactured and bonded and fixed to the lower surface of the substrate 1.

A 2 × 2 optical switch manufactured as described above is shown in FIG. 4A is a view of the 2 × 2 optical switch as viewed from above, and FIG. 4B is a cross-sectional view taken along line bb ′ in FIG. Figure, Figure 4
4C is a view in which the cross section taken along the line c-a ′ in FIG. 4A is slightly enlarged and viewed in the direction of the arrow, and FIG.
It is the figure which looked at the cross section which followed the line dd 'in (a) a little and which was seen in the direction of the arrow. As described above with reference to FIG. 7E, the surface of the mirror base m on the side of the optical fiber facing the mirror base m is not formed at a right angle to the surface of the substrate 1, but is formed slightly inclined. The mirrors 31, 32, 3 on the upper surface of the finished movable electrode plate 2
1'and 32 'are formed to be inclined at an acute angle or an obtuse angle when viewed from the surface of the movable electrode plate 2. Due to this, the reflected light will enter the port on the incident side with a height difference,
Since the light has not been properly incident on the respective lenses of the incident side optical fibers 5 and 5 ', (step 5)
, The width of the pattern of the V-shaped groove 14 in cross section is changed in accordance with the depth of the V-shaped groove 14 in cross section to be formed, that is, in proportion to the depth of the V-shaped groove 14 in cross section to be formed. The width of the pattern forming this is formed large, and the depth of the V-shaped groove 14 formed in cross section is adjusted to form a height difference between the incident side optical fiber and the emitting side optical fiber which are positioned and fixed here. .

Specifically, when the surface of the mirror facing the optical fiber side is formed to be inclined at an acute angle as viewed from the surface of the movable electrode plate 2, the V-shaped cross-section groove 14 in the exit side port 1 is a standard one. Assuming that a V-shaped standard groove having a cross section of depth is formed, patterning is performed correspondingly to a standard pattern width. The V-shaped groove 14 in the port 2 has a V-shaped groove which is slightly deeper than the standard depth. Correspondingly, the V-shaped groove 14 is patterned to have a slightly wider pattern width than the standard pattern width. The V-shaped groove 14 in cross section in the incident side port 3 is assumed to form a V-shaped standard groove in cross section having a standard depth, and is patterned to a standard pattern width correspondingly. The section V-shaped groove 14 in the port 4 forms a section V-shaped deep groove that is slightly shallower than the standard depth.
Correspondingly, patterning is performed to a narrow pattern width which is slightly narrower than the standard pattern width. By forming the pattern width for forming the V-shaped groove 14 in cross section large, the depth of the V-shaped groove 14 in cross section to be formed increases in proportion to the pattern width.

As described above, the depth of the V-shaped groove 14 in each port is formed in the relationship of port 2> port 1 port 3> port 4. However, in the embodiment, the depths of the V-shaped groove 14 in the cross section in the port 1 and the port 3 are set to be equal. As a result, the relationship of the heights of the optical fibers positioned and fixed in the V-shaped cross section 14 at each port is as follows: port 2 <port 1 port 3 <port 4.

Referring to FIG. 4, in a steady state in which the movable electrode plate 2 is not attracted downward, the light emitted from the optical fiber 4 of the port 1 is incident on the mirror 31 via the microlens 91 and is horizontally directed. And then enters the mirror 31 to be reflected. Assuming that the mirrors 31 and 32 are formed to be slightly inclined toward the facing optical fiber 4 side, the horizontally reflected light at the mirror 31 is reflected with a slightly downward component and is incident on the mirror 32. And has a slightly downward component and reflects in the horizontal direction,
The light enters the optical fiber 5 of the port 2 through the microlens 92. The light emitted from the optical fiber 4 of the port 1 is
Since the mirrors 31 and 32 have the downward component reflected twice in the horizontal direction, the level of the light when reaching the port 2 is lower than the level when the light exits from the port 1. . In consideration of this decrease in advance, the height of the optical fiber 5 of the port 2 is lowered with reference to the height of the optical fiber 4 of the port 1, and the optical fibers 4 and 5 are positioned and fixed. To set this height, the depth of the V-shaped groove 14 in cross section in the port 1 is set as a reference depth, and the depth of the V-shaped groove 14 in cross section in the port 2 is set deeper than the reference depth. For Port 3 and Port 4,
Similarly, the height of the optical fiber 4 ′ of the port 4 on the light emitting side is set higher than the height of the optical fiber 5 ′ of the port 3 on the light incident side. That is, the depth of the V-shaped cross section groove 14 of the port 4 is formed to be shallower than the standard depth, while the depth of the V-shaped cross section groove 14 of the port 3 is formed to the standard depth.

To summarize the above, when the surface of the mirror facing the optical fiber side is formed to be inclined at an acute angle as viewed from the surface of the movable electrode plate 2, the depth of the V-shaped groove 14 in cross section of the exit side port and By comparison, the depth of the V-shaped groove 14 in the cross section of the incident side port is formed deeper, so that the positioning and fixing is performed in the incident side port compared to the height of the optical fiber in the V-shaped cross section 14 which is positioned and fixed in the outgoing side port. The height of the optical fiber of the V-shaped groove 14 having a cross section is reduced. On the contrary, when the surface of the mirror facing the optical fiber side is formed to be inclined at an obtuse angle as viewed from the surface of the movable electrode plate 2, the depth of the cross section V-shaped groove 14 of the exit side port is compared with the depth of the entrance side. The V-shaped groove 14 in the cross section of the port is formed to have a shallow depth, so that the V-shaped cross section is positioned and fixed in the incident side port as compared with the height of the optical fiber positioned and fixed in the V shape groove 14 in the outgoing side port. The height of the optical fiber in the groove 14 is increased.

Although the above description has been made with reference to the 2 × 2 optical switch as an example, the present invention is based on FIG. 4 and the 1 × 1 light composed of the outgoing side optical fiber 4, the incoming side optical fiber 5 and the mirrors 31 and 32. It can also be applied to a switch, and further has 1 × 2 having a second incident side optical fiber 5 ′.
It can also be applied to an optical switch.

[0023]

As described above, according to the present invention, the cross section V of the entrance side port is compared with the height of the exit side optical fiber positioned and fixed in the cross section V-shaped groove of the exit side port.
By forming a height difference in the height of the incident-side optical fiber that is positioned and fixed in the groove, the mirror formed on the surface of the movable electrode plate has a component in the height direction and is reflected by the incident side. By positioning and fixing the incident side optical fiber at the arrival position of the light arriving at the port, it is possible to make the incident light to the incident side optical fiber proper and reduce the insertion loss of the light by the optical switch in the process of transmitting the light.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an example.

FIG. 2 is a continuation of FIG.

FIG. 3 is a diagram showing a substrate, a movable electrode plate, and a mirror that are integrally formed.

FIG. 4 is a diagram showing an example of a 2 × 2 optical switch.

FIG. 5 is a diagram showing a prior art example of a 2 × 2 optical switch.

FIG. 6 is a diagram illustrating a switching operation of a 2 × 2 optical switch.

FIG. 7 is a diagram illustrating a method of forming a mirror.

[Explanation of symbols]

1 substrate 2 movable electrode plate 21 Flexure 31, 32 Mirror 4 Outgoing side optical fiber 5 Incoming side optical fiber 8 Fixed electrode substrate

Claims (5)

[Claims] 1. A fixed electrode substrate, a substrate, a movable electrode plate attached to and coupled to the substrate via a flexure portion, a mirror formed on the surface of the movable electrode plate, and arranged on the substrate separately along straight lines parallel to each other. In an optical switch that includes an emission side optical fiber and an incidence side optical fiber, a mirror is positioned to face the emission side optical fiber and the incidence side optical fiber, and electrostatically drives a movable electrode plate to control light switching. An optical switch characterized in that the emitting side optical fiber and the incident side optical fiber for receiving the reflected light from the mirror are fixed to the substrate with a height difference. 2. The optical switch according to claim 1, wherein a second incident side optical fiber is arranged so as to face the emission side optical fiber along a straight line on which the emission side optical fiber is arranged. Optical switch to do. 3. A fixed electrode substrate, a substrate, a movable electrode plate attached to and coupled to the substrate via a flexure portion, a mirror formed on the surface of the movable electrode plate, and two straight lines parallel to each other. Equipped with an outgoing side optical fiber arranged and an incoming side optical fiber arranged facing the outgoing side optical fiber, the mirror is positioned between the outgoing side optical fiber and the incoming side optical fiber so as to face the optical fibers. ,
In an optical switch that electrostatically drives the movable electrode plate to control light switching, the light is characterized in that the emitting side optical fiber and the incident side optical fiber that receives the reflected light from the mirror are fixed to the substrate with a height difference. switch. 4. The optical switch according to any one of claims 1 to 3, wherein a V-shaped groove in cross section is formed separately on the substrate along straight lines parallel to each other, and The entrance side optical fiber is positioned and fixed, and the depth of the cross section V-shaped groove for positioning and fixing the exit side optical fiber and the cross section V-shaped groove for positioning and fixing the incidence side optical fiber for receiving the reflected light from the mirror are set to be different. An optical switch characterized by being attached. 5. The optical switch according to any one of claims 1 to 4, wherein the mirror is formed by exposing and developing a photosensitive synthetic resin and coating the surface of the structure with a metal. An optical switch characterized by that.