JPH11202373A - Light switch - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] To provide an optical switch that can be easily connected to an input / output fiber, is easy to handle, and has small loss fluctuation. SOLUTION: A groove-shaped gap provided at an intersection of a first optical waveguide 1 in a first direction and a second optical waveguide 2 in a second direction intersecting each other on a substrate and satisfying a total reflection condition. A matching liquid having a refractive index equal to that of the core portion of the optical waveguide is sealed in the optical waveguide 3, and the matching liquid is moved in the gap 3 to switch an optical path. In the area of the second optical waveguide 2 where an optical signal propagates when the optical path is switched to the second optical waveguide 2, a new third optical waveguide in the first direction is provided in parallel with the optical waveguide 1 in the first direction. 11, a gap 31 that satisfies the condition of total reflection is provided at the intersection of the optical waveguides 2 and 11, and an optical signal propagates between the optical waveguides 2 and 11 through the gap 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical switch used for optical communication and the like.

[0002]

2. Description of the Related Art A conventional optical switch 9 of this type is shown in FIG. 8 (Japanese Patent Application No. 8-231677). As shown in the figure, the first-direction optical waveguide 1 and the second-direction optical waveguide 2 embedded in a cladding layer 4 provided on a base substrate 5, and the The air gap 3 has a smooth side wall provided at an angle that substantially satisfies the condition of total reflection at the intersection, and can be moved inside the air gap 3 by using an enclosing lid 9 in which a detour 8 is formed. In this state, the refractive index matching liquid 6 was sealed.

[0003] Here, the total reflection condition means that, for example, when the signal light propagating through the waveguide reaches an air gap, the signal light is totally reflected and the propagation direction is changed to the optical waveguide 2 side. .

Further, in the optical switch 9, by controlling a heating state of a heater (not shown) provided near the gap 3, the refractive index matching liquid 6 is excluded from the vicinity of the optical waveguide in the gap 3. The optical signal entering from the input port A of the optical waveguide 1 in the first direction is reflected by the side wall of the gap 3 and propagated to the reflection port C of the optical waveguide 2 in the second direction.
By moving the refractive index matching liquid 6 to the vicinity of the optical waveguide in the gap 3, an optical signal is transmitted through the gap 3 and propagates to the transmission port B which is the terminal end of the optical waveguide 1 in the first direction. .

Thereafter, when the gap 3 is in a reflection state (a state in which the refractive index matching liquid is moving from the intersection), the path through which the optical signal propagates is a reflection optical path, and the gap 3 is in a transmission state (the refractive index matching liquid is just The path through which the optical signal propagates when the optical signal is in the state of being located at the intersection is referred to as a transmission optical path. Further, the same components are denoted by the same reference numerals.

[0006]

However, in this type of conventional optical switch 9, the connection points with the input / output ports, ie, optical fibers (not shown), are the input port A, the transmission port B, and the reflection port C. Since there are three directions, there is a drawback that handling of the optical switch 9 is difficult, for example, the connection process of input / output fibers becomes complicated.

In this type of optical switch 9, the loss of the reflected light path (hereinafter, referred to as reflection loss) is increased by the loss due to the reflection of the side wall of the gap, and the loss of the transmitted light path (hereinafter, referred to as transmission loss). ), There is also a problem that loss fluctuation accompanying optical path switching is large.

[0008]

SUMMARY OF THE INVENTION The present invention includes an intersection between a first optical waveguide in a first direction and a second optical waveguide in a second direction that intersect each other on a substrate. The optical waveguide is provided so as to straddle and fill at least a part of a groove-shaped gap having a side wall that substantially satisfies the condition of total reflection between the first optical waveguide and the second optical waveguide. A refractive index matching liquid having the same refractive index as that of the core portion is sealed, and the refractive index matching liquid is moved in the gap, so that the refractive index matching liquid is formed between the first optical waveguide and the second optical waveguide. In the optical switch for switching the optical path between, in the first direction in the region of the second optical waveguide where the optical signal propagates when the optical path is switched from the first optical waveguide to the second optical waveguide. A new first parallel or almost parallel to the optical waveguide The third optical waveguide is provided, and a gap is provided at the intersection of the second optical waveguide and the third optical waveguide, the gap substantially satisfies the condition of total reflection, and the third The first feature is that an optical signal propagates between the second optical waveguide and the third optical waveguide.

Further, the present invention provides a new first-direction optical waveguide in the optical signal propagation portion of the second-direction optical waveguide, and newly provides a question on the second-direction optical waveguide and the new first-direction optical waveguide. In addition to providing a gap, a new second direction optical waveguide is provided in a portion of the first direction optical waveguide beyond the gap in which the refractive index matching liquid is sealed, and another first direction waveguide is provided near the new first direction optical waveguide. Providing an optical waveguide, providing a gap at the intersection of the first direction optical waveguide and the new second direction optical waveguide and at the intersection of another first direction optical waveguide and the new second direction optical waveguide. The second feature. Of course, these new voids have sidewalls that satisfy nearly total internal reflection conditions.

Further, according to the present invention, a new second-direction optical waveguide is provided in a portion of the first-direction optical waveguide beyond a gap filled with the refractive index matching liquid, and the first-direction optical waveguide and the new second-direction optical waveguide are provided. A third feature is that a new gap is provided at the intersection with the optical waveguide.

According to the first aspect of the present invention, a new first-direction optical waveguide is provided in the optical signal propagation portion of the second-direction optical waveguide in parallel with the first-direction optical waveguide. By providing a gap at the intersection of the waveguide and the new first-direction optical waveguide, the optical signal propagating in the reflected light path is reflected by the gap without the refractive index matching liquid in the vicinity of the optical waveguide and is reflected by the first-direction optical waveguide. After the direction is switched to the second direction optical waveguide, the light is reflected again by the gap provided in the second direction optical waveguide and exits from the new first direction optical waveguide. Therefore, since the optical fiber connection point of the optical switch can be limited to the first direction, the optical switch can be easily inserted into the middle of the optical fiber link without taking up a mounting space.

According to the second configuration of the present invention, a new first-direction optical waveguide is provided in the optical signal propagation portion of the second-direction optical waveguide in parallel with the first-direction optical waveguide, and the second-direction optical waveguide is newly connected to the first-direction optical waveguide. A gap is provided at the intersection with the first direction optical waveguide, and a new second direction optical waveguide is formed in a portion of the first direction optical waveguide beyond the gap filled with the refractive index matching liquid, in the new first direction. Providing another first-direction optical waveguide near the optical waveguide,
A gap is provided at the intersection between the first direction optical waveguide and the new second direction optical waveguide and at the intersection between another first direction optical waveguide and the new second direction optical waveguide.

With this configuration, the optical signal propagating in the reflected light path is reflected again by the air gap and exits from the new first-direction optical waveguide. It can be limited to one direction. Further, the optical signal propagating through the transmission optical path includes an air gap at an intersection between the first direction optical waveguide and the new second direction optical waveguide and an intersection between another first direction optical waveguide and the new second direction optical waveguide. Are reflected at two places in the gap, so that the loss can be made substantially the same as the reflected light path without using an attenuator or the like.

From the above, it is possible to limit the connection point of the optical switch to the optical fiber in the first direction, and it is possible to reduce the loss fluctuation due to the switching of the optical path. Further, according to the third configuration of the present invention, a new second-direction optical waveguide is provided in a portion of the first-direction optical waveguide beyond the gap in which the refractive index matching liquid is sealed, and the first-direction optical waveguide is newly added to the first-direction optical waveguide. A gap is provided at the intersection with the second direction optical waveguide. With such a configuration, the optical signal propagating through the transmission optical path is reflected by the gap of the new second-direction optical waveguide and emitted in the same direction as the reflection optical path.

Therefore, the connection point with the optical fiber can be limited to two adjacent sides of the optical switch. Moreover, since the number of times of reflection of the optical signal can be reduced to one in all the optical paths, the loss of the optical switch can be set to a low value. That is, an optical switch with low loss and small loss fluctuation can be realized, and by limiting the connection point with the optical fiber in two directions, the handleability of the optical switch can be improved, and the space for routing the optical fiber even in a board mounted state Can be reduced.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIGS. 1, 2 and 7 show an optical switch 100 according to a first embodiment of the present invention. In this optical switch 100, a new third optical waveguide 11 in the first direction parallel to the optical waveguide 1 in the first direction is provided in the optical signal propagation portion of the optical waveguide 2 in the second direction. A gap 31 is added at the intersection of the waveguide 2 and the new third optical waveguide 11.

That is, in the optical switch 100,
First optical waveguides 1 in a first direction crossing each other on a substrate
A groove-shaped gap 3 is provided at an intersection between the first optical waveguide 2 and the second optical waveguide 2 in the second direction so as to include and cross the intersection. The gap 3 has a side wall that substantially satisfies the condition of total reflection between the first optical waveguide 1 and the second optical waveguide 2,
A refractive index matching liquid having the same refractive index as the core portions of the optical waveguides 1 and 2 is sealed so as to fill at least a part thereof.

Therefore, the optical path between the first optical waveguide 1 and the second optical waveguide 2 can be switched by moving the refractive index matching liquid in the gap 3. Furthermore, in the present embodiment, when the optical path is switched from the first optical waveguide 1 to the second optical waveguide 2, the region of the second optical waveguide 2 where the optical signal propagates is parallel to the optical waveguide 1 in the first direction. Alternatively, the third optical waveguide 11 in a new first direction is almost parallel.
And a gap 31 is provided at the intersection of the second optical waveguide 2 and the third optical waveguide 11, the gap 31 substantially satisfies the condition of total reflection, and the second An optical signal propagates between the optical waveguide 2 and the third optical waveguide 11.

As a result, in this embodiment, the optical switch 10
The connection point with the 0 optical fibers 63 and 64 can be limited to the first direction. For this reason, as shown in FIG.
00 can be easily inserted between the optical fibers 63 and 64 without taking up much mounting space.

Optical switch 101 according to a modification of this embodiment
Is shown in FIG. In the optical switch 101, when the installation direction of the gap provided at the intersection of the new first direction optical waveguide 11 and the second direction optical waveguide 2 is inclined in the opposite direction as the gap 32, the optical signal propagating in the reflected light path Is reflected by the air gap 31 again, and C2 (optical switch 1) of the new first-direction optical waveguide 11
No. 01 (port A side).
Therefore, by using the optical switch 100 or the optical switch 101 properly, it is possible to flexibly cope with various mounting forms.

Embodiment 2 FIGS. 3, 4, 5, and 7 show an optical switch according to a second embodiment of the present invention. FIG.
In the optical switch 102 shown in (1), a new first direction optical waveguide 11 is provided in the optical signal propagation portion of the second direction optical waveguide 2 in parallel with the first direction optical waveguide 1, and the second direction optical waveguide 2 and the new A gap 31 at the intersection with the one-way optical waveguide 11
Is provided.

Further, a new second-direction optical waveguide 21 is provided in a portion of the first-direction optical waveguide 1 beyond the gap 3 in which the refractive index matching liquid 6 is sealed, and is provided in the vicinity of the new first-direction optical waveguide 11. Another first-direction optical waveguide 12 is provided, and an intersection between the first-direction optical waveguide 1 and the new second-direction optical waveguide 21 and another first-direction optical waveguide 12 and a new second-direction optical waveguide 21 are formed. Are provided with gaps 33 and 34, respectively.

As a result, the optical signal transmitted through the gap 3 in a state where the refractive index matching liquid 6 can be seen near the optical waveguide becomes the intersection of the first direction optical waveguide 1 and the new second direction optical waveguide 21. Are reflected at two points, namely, the gap 33 and the gap 34 at the intersection of another first-direction optical waveguide 12 and the new second-direction optical waveguide 21, so that there is no refractive index matching liquid 6 near the optical waveguide. The same reflection loss as when the optical signal is reflected by the gap 3 (optical path in the reflective state) is added to the optical path in the transmissive state.

As described above, the connection point of the optical switch 102 with the optical fiber 62 can be limited in the first direction, and the loss fluctuation accompanying the switching of the optical path can be reduced. That is, in addition to the advantages of the first embodiment,
There is an advantage that loss fluctuation of the optical switch due to optical path switching can be suppressed.

As shown in FIG. 4, in the optical switch 103 (in the figure, the case of N = 2) applicable to the standby system of the N + 1 configuration, the gap 3, in which the refractive index matching liquid is sealed, 3 'is provided, and an optical waveguide 11 and a gap 31 for changing the direction of the exit port of the reflected light path are provided. Further, the optical waveguides 12, 13, 21, 22 and the gaps 33, 3 are so arranged that the respective transmission optical paths do not overlap each other.
4, 36, 27 are provided.

At this time, in the optical switch 103, the transmission optical path is changed from the input port A to the gap 3 in the transmission state to the gap 33.
→ Gap 34 → Transmissive port B1 (hereinafter referred to as “transmitted optical path”) and entrance port A ′ → Transmissive gap 3 ′ → Gap 36
→ air gap 37 → transmission port B 1 ′ (hereinafter referred to as transmission light path), and reflection port as incident port A →
Gap 3 in the reflection state → gap 31 → reflection port C3 (hereafter,
There are two paths, namely, a reflection optical path) and an input port A ′ → a gap 3 ′ in a reflection state → a gap 31 → a reflection port C3 ′ (hereinafter, a reflection optical path).

Therefore, even in the optical switch 103 having the N + 1 configuration, the connection point with the optical fiber (not shown) can be limited in the first direction. Further, since the loss occurring at the intersection of the optical waveguides is extremely small, the loss of the transmitted light path and the reflected light path is almost the same, and the loss of the transmitted light path and the reflected light path can be made almost the same. In the following description, the optical switch is limited to a 1 × 1 scale switch. However, as in FIG. 4, by providing an optical waveguide and an air gap so that transmitted optical paths do not overlap with each other, an N + 1 configuration optical switch is provided. A switch can be easily realized.

[Embodiment 2 '] FIG. 5 shows another configuration of the optical switch according to the second embodiment of the present invention. Most of the optical switch 104 employs the same configuration as the optical switch 102 except that a gap 32 provided at the intersection of the new first-direction optical waveguide 11 and the second-direction optical waveguide 2 has another gap. The direction of the gap 35 provided at the intersection of the one-way optical waveguide 12 and the new second-direction optical waveguide 21 is provided with the corresponding gaps 31 and 34 in the optical switch 102.

With such a configuration, the optical signal in the transmitted light path is transmitted from the input port A to the gap 3 in the transmitted state.
Propagation proceeds in the order of the gap 33, the gap 35, and the transmission port B2. Also, the optical signal in the reflected light path is input port A →
The light propagates in the order of the gap 3 in the reflection state, the gap 32, and the reflection port C4.

Accordingly, in the optical switch 104, the connection point with the optical fiber 62 can be concentrated on one side of the optical switch 104. Therefore, the handleability of the optical switch 104 is extremely good, and as shown in FIG. Can be mounted on a substrate or the like. Moreover, there is a merit that the loss fluctuation of the optical switch accompanying the optical path switching can be suppressed.

Third Embodiment FIGS. 6 and 7 show an optical switch according to a third embodiment of the present invention. This optical switch 1
05, the refractive index matching liquid 6 of the first direction optical waveguide 1
A new second-direction optical waveguide 21 is provided in a portion beyond the gap 3 in which is enclosed, and a gap 33 is provided at the intersection of the first-direction optical waveguide 1 and the new second-direction optical waveguide 21.

Thus, in the reflected light path, the optical signal propagates in the order of the input port A → the air gap 3 → the reflection port C5. The optical signal that has passed through the gap 3 in the transmission state is reflected by the gap 33 at the intersection of the first direction optical waveguide 1 and the new second direction optical waveguide 21 and is located on the same side as the reflection port C5. Emitted from B3.

Therefore, the optical fiber 6 of the optical switch 105
Since the connection points with the optical switches 0 and 61 can be limited to two sides adjacent to each other of the optical switch, as shown in FIG.
Even when the optical fiber is mounted on the optical switch 105, the space for the optical fibers 60 and 61 connected to the optical switch 105 can be reduced. Furthermore, since the optical signal is reflected only once in both the transmitted light path and the reflected light path, loss fluctuation due to switching of the light path can be reduced, and the loss in the light path can be reduced.

In FIGS. 1 to 6 and 8, the first direction and the second direction are drawn so as to be orthogonal to each other, but the intersection angle is not limited to 90 degrees.

[0035]

As described above in detail with reference to the embodiments, according to the present invention, the optical fiber connection point of the optical switch can be limited to a certain direction. It can be easily inserted without taking up mounting space. Further, according to the present invention, the connection point of the optical switch with the optical fiber can be limited to a certain direction, and the loss fluctuation accompanying the switching of the optical path can be reduced.

Further, according to the present invention, the connection point with the optical fiber can be limited to two sides adjacent to each other in the optical switch, and the number of times of reflection of the optical signal is 1 in all the optical paths.
Since the number of times can be increased, the loss of the optical switch can be adjusted to a low value. That is, it is possible to realize an optical switch with low loss and small loss fluctuation, and to improve the handleability of the optical switch by limiting the connection points to the optical fiber in two directions, and to manage the optical fiber even in a board mounted state. Can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration example of an optical switch according to a first embodiment of the present invention.

FIG. 2 is a plan view showing another configuration example of the optical switch according to the first embodiment of the present invention.

FIG. 3 is a plan view illustrating a configuration example of an optical switch according to a second embodiment of the present invention.

FIG. 4 is a plan view showing a configuration example when a plurality of optical paths are provided in an optical switch according to a second embodiment of the present invention.

FIG. 5 is a plan view showing another configuration example of the optical switch according to the second embodiment of the present invention.

FIG. 6 is a plan view illustrating a configuration example of an optical switch according to a third embodiment of the present invention.

FIG. 7 is a plan view showing a state where the optical switch according to the embodiment of the present invention is mounted on a printed circuit board.

FIG. 8 is a perspective view showing a configuration example of a conventional optical switch.

[Explanation of symbols]

1,1 ′, 11,12,13 Optical waveguide in first direction 2,21,22 Optical waveguide in second direction 3,3 ′ Air gap in which refractive index matching liquid is filled in a movable state 4 Cladding layer Reference Signs List 5 Base substrate 6 Refractive index matching liquid 7 Sealing lid 8 Detour 9 Optical switch 31, 32, 33, 34, 35, 36, 37 Air gap 40 Printed circuit board 50, 51 Package connector 60, 61, 62, 63, 64 Output optical fiber 100, 101, 102, 103, 104, 105 Optical switch

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazumasa Kaneko, 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Yasuhide Nishida 3--19, Nishishinjuku, Shinjuku-ku, Tokyo No. 2 Nippon Telegraph and Telephone Corporation

Claims (3)

[Claims] A first optical waveguide in a first direction and a second optical waveguide in a second direction that intersect with each other on a substrate, the intersection being provided so as to include and cross over the intersection. Refraction having the same refractive index as the core of the optical waveguide so as to fill at least a part of the groove-shaped gap having a side wall that substantially satisfies the condition of total reflection between the first optical waveguide and the second optical waveguide. The refractive index matching liquid is sealed, and the refractive index matching liquid is moved in the gap so that the refractive index matching liquid switches an optical path between the first optical waveguide and the second optical waveguide. In the switch, the optical signal propagates when the optical path is switched from the first optical waveguide to the second optical waveguide. Providing a third optical waveguide in a new first direction, And a gap is provided at the intersection of the second optical waveguide and the third optical waveguide, the gap substantially satisfies the total reflection condition, and the second optical waveguide and the third optical waveguide are provided through the gap. An optical switch, wherein an optical signal propagates between optical waveguides. 2. The optical switch according to claim 1, wherein
When the optical path is switched from the first optical waveguide to the second optical waveguide by the movement of the refractive index matching liquid in the gap, an optical signal is not propagated. A fourth optical waveguide is provided in the direction of, and a fifth optical waveguide in another first direction is provided between the first optical waveguide and the third optical waveguide, and the first optical waveguide and At the intersection of the fourth optical waveguide and the intersection of the fourth optical waveguide and the fifth optical waveguide, the optical signal propagates between the waveguides that satisfy the total reflection condition and intersect each other. An optical switch having a gap. 3. An intersecting portion between a first optical waveguide in a first direction and a second optical waveguide in a second direction intersecting with each other on the substrate is provided so as to include and cross over the intersecting portion. Refraction having the same refractive index as the core of the optical waveguide so as to fill at least a part of the groove-shaped gap having a side wall that substantially satisfies the condition of total reflection between the first optical waveguide and the second optical waveguide. The refractive index matching liquid is sealed, and the refractive index matching liquid is moved in the gap so that the refractive index matching liquid switches an optical path between the first optical waveguide and the second optical waveguide. In the switch, the optical signal propagates when the optical path is not switched from the first optical waveguide to the second optical waveguide.The optical signal propagates in a region of the first optical waveguide parallel or substantially parallel to the optical waveguide in the second direction. Providing a new fourth optical waveguide in the second direction And a gap is provided at the intersection of the first optical waveguide and the fourth optical waveguide, the gap substantially satisfies the condition of total reflection, and the first optical waveguide and the fourth An optical switch, wherein an optical signal propagates between the optical waveguides.