JPH09297230A - Waveguide type modified 2x2 optical switch and waveguide type matrix optical switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the increasing of a circuit length caused by wave-guide extension parts of cross waveguides to be generated in a bus-non-dependent type constitution by laying out the waveguide extension part of cross waveguides being generated in-between and the waveguide extension part of cross waveguides in double gate type optical switch elements to be generated in a bus non-independent type in the same waveguide extension part en bloc. SOLUTION: When double gate type optical switch elements are used as a 2×2 optical switch element, cross waveguides 19, 29 of input line optical waveguides and output line optical waveguides in the double gate type optical switch elements are arranged at proximate positions in optical switch elements constituted by being paired. Moreover, when cross waveguides 31a, 32b to be generated in-between switch stages are arranged in the vicinity of the cross waveguides 19, 29 of input line optical waveguides and output line optical waveguides in the optical switch elements and then cross waveguides 19, 29, 31a, 32b of four places are constituted en bloc in one waveguide extension part 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide type optical switch used in the field of optical communication and the like, and in particular, it is resistant to fabrication errors and has an excellent extinction ratio, and has a short optical path length (circuit length).
Waveguide type deformation that can be compactly integrated on a single substrate 2 ×
The present invention relates to a technique effectively applied to a layout configuration of a two-optical switch pair and a waveguide type matrix optical switch using the same.

[0002]

2. Description of the Related Art In recent years, optical fiber, light-receiving elements and light-emitting elements have become more and more popular due to cost reduction and optical communication in communication networks is becoming widespread. Almost all communication lines in relay networks have been replaced by optical fiber communication. There is. Further, the optical communication network is changed from point-to-point optical communication that individually connects nodes to optical communication network of a network structure in which a plurality of nodes including an access network are connected as optical signals without being converted into electric signals. It is time to develop. There is an urgent need to develop various optical components such as optical branching / coupling devices, optical multiplexer / demultiplexers, and optical switches. Among them, optical switches (especially matrix optical switches that can be strictly non-blocking switches) are used as components used for switching optical fiber lines freely according to demand, and for switching to secure detours in the event of line failure. The need is growing.

A bulk type, a waveguide type, etc. have been proposed as an implementation form of the optical switch. The bulk type is composed of movable prisms and lenses as constituent elements, and has the advantage of less wavelength dependence and relatively low loss, but it is not suitable for mass production because the assembly adjustment process is complicated. There is a problem that it is expensive, and it has not spread widely. The waveguide type is based on an optical waveguide on a flat substrate that is manufactured using microfabrication technology using photolithography and various etchings, and is excellent in terms of mass productivity and miniaturization. Is expected as the optical switch of.

[0004] Further, conventionally, attempts have been made to fabricate a matrix optical switch by using optical waveguides of various materials. Among them, a silica optical waveguide fabricated on a silicon substrate is used for heat generation. The thermo-optical matrix optical switch utilizing the optical effect is excellent in stability and compatibility with optical fibers, and is expected as the most promising means for realizing a practical matrix optical switch.

FIG. 9A shows N × N which is the object of the present invention.
It is a structure conceptual diagram of a 4x4 matrix optical switch as an example of a matrix optical switch. This 4 × 4 matrix optical switch has four input line optical waveguides 1a-1d and 2a-
2d, 3a-3d, 4a-4d and four output line optical waveguides 1
b-1c, 2b-2c, 3b-3c, 4b-4c is 4 × 4 =
It has a structure that intersects at 16 points. At this intersection, a 2 × 2 optical switch element S11, which is the minimum unit of the optical switch,
S12, ..., S44 are arranged. Each of these optical switch elements is switched on / off (ON / OFF) to switch from the cross state shown in FIG. 9B to the bar state shown in FIG. 9C. Such a matrix optical switch has a strictly non-blocking configuration, and in order to connect an arbitrary input line optical waveguide and output line optical waveguide, this input line optical waveguide and this output line optical waveguide intersect. You only have to connect one intersection.

FIG. 10 shows an entire conventional thermo-optical 4 × 4 waveguide type matrix optical switch which is manufactured by using a silica single mode waveguide corresponding to the 4 × 4 matrix optical switch of FIG. FIG. FIG. 11 (a) is an enlarged plan view of a double gate type 2 × 2 optical switch element (Japanese Patent Laid-Open No. 6-51354) used for the 2 × 2 switch element at each intersection, and FIG. (C) is C- in FIG. 11 (a)
It is sectional drawing cut | disconnected along the C'line and the DD 'line.

These waveguides are formed on a silicon substrate by a known combination of the flame hydrolysis reaction deposition method and the reactive ion etching technique.

As shown in FIG. 11 (a), the optical switch element includes the input line optical waveguides 11a-11b and the output line optical waveguide 1 which intersect each other at an angle θ where crosstalk can be ignored.
2a-12b plus bypass waveguides 13a-13b 3
It is composed of a book optical waveguide and has two Mach-Zehnder interferometer circuits 18a and 18b.

That is, the input line optical waveguides 11a-11b
And a part of the bypass waveguides 13a-13b are close to each other at two locations, form directional couplers 14a and 15a, constitute a first Mach-Zehnder interferometer circuit, and output the bypass waveguides 13a-13b. Part of the line optical waveguides 12a-12b are close to each other at two locations to form the directional couplers 14b and 15b, and form a second Mach-Zehnder interferometer circuit.

The optical coupling rate of these directional couplers is set to 50% at the signal light wavelength. In these Mach-Zehnder interferometer circuits, the difference in the optical path lengths of the two waveguides connecting the two directional couplers is accurately set to one-half the signal wavelength in the OFF state. At least one of the two waveguides is loaded with a thin film heater for changing the optical path length by utilizing the so-called thermo-optic effect.

In the OFF state (non-energization of the thin film heater), in the first Mach-Zehnder interferometer circuit, the two optical waveguides that connect the two directional couplers are halved of the signal wavelength. Since the optical path lengths are different, if the coupling ratios of the two directional couplers are the same, regardless of the absolute value of the coupling ratios, the input line optical waveguide 11a-1 can be produced by the known interference principle.
The signal light transmitted to 1b is apparently the bypass waveguide 13a-
100% input line optical waveguide 11a without being transmitted to 13b
Since only -11b is propagated, when viewed as a 2 × 2 optical switch element as a whole, the signal light passes through the optical switch element with a 100% cross path.

Even if the first Mach-Zehnder interferometer circuit leaks signal light into the bypass waveguides 13a-13b,
This leakage signal light apparently propagates only through the bypass waveguides 13a-13b in the second Mach-Zehnder interferometer circuit and the same principle as the first Mach-Zehnder interferometer circuit, and then propagates to the output line optical waveguides 12a-12b. Is not transmitted, there is almost no optical crosstalk into the bar path when viewed as a 2 × 2 optical switch element as a whole.

In these two Mach-Zehnder interferometers, the thermo-optical phase shifter provided on the waveguide connecting the two directional couplers is operated (the thin film heater is energized), and the optical path equivalent to the half is obtained. When the length difference is canceled and the state is turned on, the signal light transmitted to the input line optical waveguide 11a in the first Mach-Zehnder interferometer circuit is bypassed by the bypass waveguide 13a-1.
3b, and further to the output line optical waveguide 12b by the second Mach-Zehnder interferometer circuit, the state of the optical switch element can be switched to the bar path.

As described above, the double gate type 2 × 2 optical switch element is a two-stage Mach-Zehnder interferometer circuit 18
Since the optical crosstalk is controlled by the double barrier consisting of a and 18b, it is possible to realize a 2x2 optical switch element with an extremely high extinction ratio, and it is expected from the viewpoint of expanding the range of application of the matrix optical switch to the system. ing.

FIG. 14 is a diagram showing another conventional 2 × 2 waveguide type optical switch, which is an example of the waveguide type 2 × 2 optical switch using only one Mach-Zehnder interferometer circuit. .

On the other hand, in an N × N strictly non-blocking waveguide type optical switch constructed by connecting N ² 2 × 2 waveguide type optical switch elements, the connection as shown in FIG. As a configuration in which the number of switch block stages is smaller than that of a normal matrix optical switch, a connection configuration (path independent type configuration) as shown in FIG. 12 is known (Japanese Patent Publication No. 6-66982). This path-independent configuration is basically the i-th row and j-th column (where i, j
Is an integer, and connects the lower output terminal of the optical switch element of 1 <i <N, j <N) to the upper input terminal of the optical switch element in the (i + 1) th row and the (j + 1) th column, and the upper output terminal of the i-th row.
A matrix optical switch is constructed by connecting to the input terminal below the optical switch element at row 1 and column j + 1.

At first glance, this path-independent type optical switch seems to be completely different in logic configuration from the ordinary matrix type optical switch, but in order to connect an arbitrary input waveguide and an arbitrary output waveguide, The logical structure that can be connected by driving only one 2 × 2 waveguide type optical switch element is the same as a normal matrix optical switch.

It will be described below that this logical configuration is the same as the conventional one. FIG. 13A is a diagram showing a so-called conventional connection configuration in, for example, a 4 × 4 matrix switch. In this connection configuration, an arbitrary input line optical waveguide and an arbitrary output line optical waveguide always have one intersection (for example, 1a-1d and 1c-1b have S11), so strict non-blocking operation is possible, and In order to connect an arbitrary input line optical waveguide and output line optical waveguide, it is sufficient to connect only one intersection where this input line optical waveguide and this output line optical waveguide intersect. That is, if the principle that an arbitrary input line optical waveguide and an arbitrary output line optical waveguide always have one intersection, the logical configuration does not change even if the arrangement of switch elements is changed from the above configuration.

First, the input line optical waveguide is divided into two parts (for example, 1a-1d is divided into 1a-1e and 1f-1d) and arranged as shown in FIG. 13B. And an output line optical waveguide are newly crossed, S12, S13, S14, S23, S24, S34
The switch elements of can be moved to this new intersection. Then, in order to connect the two divided input line waveguides, a cylinder as shown in FIG. 13C is considered, and when the circuits are arranged so that these waveguides are attached to this surface, this division is performed. The input line waveguide can be connected smoothly.

Actually, since the circuit is not manufactured on the cylinder, as shown in FIG. 13D, the circuit on the plane is arranged by two-dimensionally projecting the arrangement on the cylinder onto the plane. To be realized. In this configuration, the waveguides connecting the respective switch elements intersect each other, and although the appearance is completely different from that of FIG. 13A, the arbitrary input line optical waveguide and the arbitrary output line optical waveguide always have one intersection. The principle of possessing has not changed and is the same as before.

Here, although the description has been made specifically for the 4 × 4 matrix switch, by applying the same idea, this configuration can be applied to the N × N matrix switch.
Just like a normal matrix optical switch, you can connect any input waveguide to any output waveguide by using only one 2
It can be easily understood that the logical configuration is such that the waveguide optical switch element of × 2 can be connected by driving.

In the N × N strictly non-blocking waveguide type optical switch, the number of switch stages in which 2 × 2 waveguide type optical switches are combined is 2N− in a normal matrix configuration.
While one stage is required, only N stages are required in the path-independent configuration. Therefore, in the path-independent configuration, the number of switch stages can be reduced to about half as compared with the normal matrix configuration, and thus the circuit length (optical path length) can be expected to be significantly reduced. In addition, reduction in loss can be expected by shortening the circuit length (optical path length).

[0023]

SUMMARY OF THE INVENTION The present inventor has found the following problems as a result of studying the above conventional technology.

In the conventional path-independent type structure, in the waveguide connecting each switch element between the number of switch stages, an intersection between the waveguides, which is not the matrix type structure, is newly generated. Therefore, in order to suppress the loss at this intersection and the crosstalk between the waveguides, it is necessary to intersect these two waveguides at a certain crossing angle. Therefore, it is mainly composed of curved waveguides before and after this intersection. Waveguide expansion part 5
It was necessary to provide 1a, 51b, 51c.

Therefore, even if the number of switch block stages is reduced from the normal matrix type configuration to the path-independent type configuration, a waveguide expanding section that increases the circuit length (optical path length) is required on the contrary. There is a problem that the effect of shortening the circuit length (optical path length) due to the decrease in the number cannot be sufficiently obtained.

An object of the present invention is to use an optical switch element having a constitution capable of obtaining the above-mentioned high extinction ratio for each optical switch element, and to reduce the circuit length (optical path length) significantly. An object of the present invention is to provide a technique capable of providing an optical waveguide layout that suppresses the influence of the increase in the circuit length (optical path length) caused by the waveguide expansion portion of the crossed waveguide that occurs in the path-independent configuration.

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

[0028]

The outline of the representative one of the inventions disclosed in the present application will be briefly described as follows.

(1) A waveguide type modified 2 × 2 optical switch pair consisting of two input line optical waveguides, two output line optical waveguides and two bypass optical waveguides, the input section of which is the first
And a first 1 × 2 optical switch having the input line optical waveguide as the output section and the output section as the first input line optical waveguide and the first bypass optical waveguide, and the input section as the second input line optical waveguide and the output section. A second 1 × 2 optical switch serving as the second input line optical waveguide and a second bypass optical waveguide; and an input section using the first output line optical waveguide and the second bypass optical waveguide as output sections. A first 2 × 1 optical switch that serves as the first output line optical waveguide; an input unit that serves as the second output line optical waveguide and the first bypass optical waveguide; and an output unit that serves as the second output line optical waveguide A second 2 × 1 optical switch as a waveguide,
Input line waveguide crosses the second output line waveguide and the second input line waveguide in this order after forming the first 1 × 2 optical switch, and the second input line waveguide The line waveguide intersects with the first output line waveguide and the first input line waveguide in this order after forming the second 1 × 2 optical switch, and The waveguide is the first 2
Before forming a × 1 optical switch, the second output line waveguide and the second input line waveguide are crossed in this order, and the second output line waveguide is connected to the second 2 × After constructing one optical switch, the first output line waveguide and the first input line waveguide are crossed in this order, and a total of four crossings are the same as those of the first 1 × 2 optical switch. A second 1 × 2 optical switch, the first 2 × 1 optical switch, and the second 2
It is a waveguide type modified 2 × 2 optical switch located near the center of the region surrounded by the × 1 optical switch.

(2) A waveguide type matrix optical switch including at least 2M (M is a positive integer) input line optical waveguides and 2M output line optical waveguides, each having one input line optical waveguide. A waveguide type 2 × 2 optical switch comprising an output line optical waveguide and a waveguide type modified 2 × 2 optical switch,
M pieces of the waveguide type modified 2 × 2 optical switches are arranged in parallel to form a (2k−1) th stage (k is an integer of 1 or more and M or less), and the waveguide type 2 × 2 optical switch, ( M-1) number of the waveguide type modified 2 × 2 optical switches, the waveguide type 2 ×
Two optical switches are arranged in parallel in this order to form a 2k-th stage, and a total of 4M optical waveguides of the 2M input-line optical waveguides and the 2M output-line optical waveguides are crossed between the respective stages. It is a waveguide type matrix optical switch that is connected without performing the above.

(3) A waveguide type matrix optical switch including at least (2M-1) (M is a positive integer of 2 or more) input line optical waveguides and (2M-1) output line optical waveguides. And (2M-1) switch stages each including a waveguide type 2 × 2 optical switch consisting of one input line optical waveguide and one output line optical waveguide and the waveguide type modified 2 × 2 optical switch pair. The odd-numbered switch stages are constituted by the waveguide type 2 × 2 optical switch and (M−1) waveguide type modified 2 × 2.
Optical switch pairs are arranged in parallel in this order to configure
The even-numbered switch stages are configured by arranging (M-1) pieces of the waveguide type modified 2 × 2 optical switch pairs and the waveguide type 2 × 2 optical switches in parallel in this order, and between the stages. And the (2M-1) input line optical waveguides and the (2M-)
1) A waveguide type matrix optical switch in which a total of 2 (2M-1) optical waveguides of output line optical waveguides are connected without crossing each other.

(4) A waveguide type matrix optical switch including at least (2M-1) (M is a positive integer of 2 or more) input line optical waveguides and (2M-1) output line optical waveguides. And (2M-1) switch stages each including a waveguide type 2 × 2 optical switch consisting of one input line optical waveguide and one output line optical waveguide and the waveguide type modified 2 × 2 optical switch pair. The odd-numbered switch stages are configured to be (M-1)
This waveguide-type modified 2 × 2 optical switch and the waveguide-type modified 2 × 2 optical switch are arranged in parallel in this order, and an even-numbered switch stage is the waveguide-type 2 × 2 optical switch. The (M-1) waveguide-type modified 2 × 2 optical switch pairs are arranged in parallel in this order, and the (2M-1) input line optical waveguides and the ( 2M
-1) A waveguide type matrix optical switch in which a total of 2 (2M-1) optical waveguides of output line optical waveguides are connected without crossing each other.

(5) In the waveguide type matrix optical switch according to any one of (2) to (4), the waveguide type modified 2 × 2 optical switch is the waveguide according to claim 1. It is a modified optical switch.

(6) In the waveguide type matrix optical switch according to any one of (2) to (5), the waveguide type 2 × 2 optical switch includes one input line optical waveguide and one input line optical waveguide. A 1 × 2 optical switch including an output line optical waveguide and one bypass optical waveguide, the input section being the input line optical waveguide, the output section being the input line optical waveguide and the bypass optical waveguide, and the input section being the output A line optical waveguide, the bypass optical waveguide, and a 2 × 1 optical switch having an output unit as the output line optical waveguide are included, and the input line optical waveguide and the input line optical waveguide are provided between the 1 × 2 optical switch and the 2 × 1 optical switch. It is a waveguide type 2 × 2 optical switch in which output line optical waveguides intersect.

(7) In the waveguide type matrix optical switch of the above (6), in the 1 × 2 optical switch and the 2 × 1 optical switch, two optical waveguides are close to each other at two locations, and two directional characteristics are provided. It is a Mach-Zehnder interferometer circuit that constitutes a coupler and has a switch drive terminal.

(8) In the waveguide type matrix optical switch of (6), the 1 × 2 optical switch and the 2 × 1 optical switch are Y-branch type switches having switch drive terminals.

(9) In the waveguide type matrix optical switch of the above (6), in the 1 × 2 optical switch and the 2 × 1 optical switch, two optical waveguides are close to each other at one place, and a switch drive terminal is provided. It is a directional coupler provided.

That is, the present invention is shown in FIGS.
1 (d) or the 2 × 2 optical switch of FIG. 11 (e) is basically arranged so that the intersections are spatially close to each other.
As a result, for example, the crossing portion can be downsized in the w direction in the figure as compared with, for example, one in which two optical switches in FIG.

The waveguide type optical matrix of the present invention is based on the waveguide type modified 2 × 2 optical switch pair and the 2 × 2 optical switch of FIG. 11 (a), FIG. 11 (d) or FIG. 11 (e). As a constitution, it is arranged like the above-mentioned means (2) to (9).

In the glass optical waveguide using quartz glass or the like which is widely used at present, a thermo-optical phase shifter using a thin film heater is used as a phase shifter, and the crossing angle is 20 degrees or more at the intersection between the waveguides. It is preferable.

In the path-independent structure, the optical switch elements are arranged in a checkerboard pattern in which the optical switch elements in which the arrangement of the input line optical waveguide and the output line optical waveguide is in the positive direction and the optical switch elements in the vertically inverted downward direction are arranged. To be done. Therefore, when the double gate type optical switch element is used as the 2 × 2 optical switch element as in the present invention, the cross waveguide of the input line optical waveguide and the output line optical waveguide in the double gate type optical switch element is The optical switch elements configured as a pair as described above are arranged in close proximity.

Therefore, the cross waveguide of the input line optical waveguide generated between the switch stages on the output end side of the switch element and the cross waveguide of the output line optical waveguide generated between the switch stages on the input end side of the switch element are described above. It can be incorporated into an optical switch element configured as a pair. Further, by arranging the cross waveguide generated between these switch stages in the vicinity of the cross waveguide of the input line optical waveguide and the output line optical waveguide in the optical switch element, these four cross waveguides are integrated. It can be configured with one waveguide expanding section.

As described above, the waveguide development part of the cross waveguides generated between the switch stages which is generated in a path independent type and the waveguide development part of the cross waveguides in the double gate type optical switch element are collectively described. By laying out in the same waveguide expansion part, it is not necessary to newly provide the waveguide expansion part of the crossed waveguide generated between the switch stages, and the effect of reducing the number of stages by half by adopting the path independent type is sufficient. It is possible to drastically reduce the circuit length (optical path length), and it is possible to reduce the insertion loss while using the double gate type optical switch element that can obtain a high extinction ratio.

[0044]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments (examples) of the present invention will be described below in detail with reference to the drawings.

In all the drawings for explaining the embodiments, parts having the same functions are designated by the same reference numerals, and the repeated description thereof will be omitted.

In the following embodiments, a silica single mode optical waveguide formed on a silicon substrate is used as an optical waveguide, and a thermo-optical Mach-Zehnder interferometer circuit type 2 × 2 optical switch is used as an optical switch element. The waveguide type matrix optical switch described above will be described. This is because this combination can provide a waveguide-type matrix optical switch having excellent connectivity with a single-mode optical waveguide and having no polarization dependence. However, the present invention is not limited to the above combination.

(Embodiment 1) FIGS. 1 and 4 show an embodiment of an N × N matrix optical switch according to the present invention (particularly N = 2).
4 × 4 of Embodiment 1 as an example of M, M: positive integer)
It is a figure which shows schematic structure of a matrix optical switch.

1 (a), 1 (b) and 1 (c) show the waveguide type deformation 2 × 2 according to the present invention in which two 2 × 2 optical switch elements used in the first embodiment are arranged in pairs. FIG. 1A is a diagram for explaining an optical switch pair, and FIG. 1A shows the first embodiment.
2 is a plan view in which two 2 × 2 matrix optical switch elements are arranged in pairs, FIG. 1B is a sectional view taken along line AA ′ shown in FIG. Figure 1 (c) is
It is sectional drawing cut | disconnected along the BB 'line shown to (a).

In FIG. 1, 1 is a silicon substrate, 2 is a quartz glass clad layer, and 11a-11b and 21a-21b.
Is a silica-based input line waveguide core, 12a-12b, 22a-2
2b is a silica-based output line waveguide core, 13a-13b, 23
a-23b is a silica-based bypass waveguide core, 14a, 14
b, 15a, 15b, 24a, 24b, 25a, 25b
Is a directional coupler.

16a, 16b, 17a, 17b, 26
a, 26b, 27a and 27b are thin film heaters (phase shifters), 18a and 28a are first Mach-Zehnder interferometer circuits, 18b and 28b are second Mach-Zehnder interferometer circuits, and 19 and 29 are double gate type optical switch elements. , A cross waveguide of the input line optical waveguide and the output line optical waveguide, 31a is a cross waveguide of the input line optical waveguide generated between the switch blocks on the output end side of the switch element, 31b is a switch block on the input end side of the switch element A crossed waveguide of the output line optical waveguides generated between 30 and 30 is a waveguide development portion.

Waveguide type deformation 2 × 2 used in the first embodiment
A 2 × 2 optical switch pair in an optical switch is composed of two input line optical waveguides and two bypass optical waveguides, the input section is a first input line optical waveguide, and the output section is the first input line optical waveguide. And a first bypass optical waveguide which is a first one
A × 2 optical switch, a second 1 × 2 optical switch having an input section as a second input line optical waveguide and an output section as the second input line optical waveguide and a second bypass optical waveguide, and an input section. A first 2 × in which the first output line optical waveguide and the second bypass optical waveguide are used and the output section is the first output line optical waveguide
And a second 2 × 1 optical switch in which the input section is the second output line optical waveguide and the first bypass optical waveguide and the output section is the second output line optical waveguide.

The first input line waveguide is the first input line waveguide.
After constructing a × 2 optical switch, it intersects with the second output line waveguide and the second input line waveguide in this order, and the second input line waveguide is the second 1 × 2 After configuring an optical switch, the optical switch intersects with the first output line waveguide and the first input line waveguide in this order, and the first output line waveguide is the first 2 × 1 optical switch. Before configuring the second output line waveguide and the second input line waveguide in this order, the second output line waveguide includes the second 2 × 1 optical switch. After being configured, the first output line waveguide and the first input line waveguide are crossed in this order, and these four crossings in total are the first 1 × 2 optical switch and the second 1 It is located near the center of the area surrounded by the × 2 optical switch, the first 2 × 1 optical switch, and the second 2 × 1 optical switch.

In addition, in the present Embodiment 1, in the above-mentioned 1 × 2 optical switch and 2 × 1 optical switch, two waveguides, which are switch elements that have a proven track record in silica glass waveguides, are used.
A Mach-Zehnder interferometer having two directional couplers arranged close to each other and having a switch driving element is used.

The waveguide type modified 2 × 2 optical switch pair has a basic structure of a 1 × 2 optical switch and a 2 × 1 optical switch. The Mach-Zehnder interferometer shown in FIG.
It is possible to use the Y-branch optical waveguide shown in (a), the directional coupler shown in FIG.

FIG. 4 is an overall plan layout of the first embodiment, SLU is a region where the waveguide type modified 2 × 2 optical switch pair of FIG. 1 is arranged, and S23 and S41 are shown in FIG.
The conventional double-gate type 2 × 2 optical switch element shown in FIG. 11 is a region arranged in the same direction vertically (meaning “with respect to the direction of FIG. 11”), and S 32 and S 14 are shown in FIG. 11. This is a region in which the conventional double gate type 2 × 2 optical switch elements are arranged upside down (meaning “with respect to the direction of FIG. 11”). 1a-1d, 2a-
2d, 3a-3d, 4a-4d are input line optical waveguides, 1c-
1b, 2c-2b, 3c-3b, 4c-4b are output line optical waveguides, S11, S12, ..., S44 are 2 × 2 optical switch elements, SLU is a waveguide type modified 2 × 2 optical switch pair, #
1, # 2, ..., # 4 are optical switch stages.

In the first embodiment, as shown in FIGS. 1 and 4, a double gate type optical switch element and a path independent structure are combined, and the double gate type optical switch element is arranged in the forward direction. Guided type deformation 2 ×
Two optical switch pairs are configured. That is, 15a, 15b, 15c of the waveguide expansion part generated between the optical switch stages
The crossed waveguides 31a and 31b are incorporated in the waveguide type modified 2 × 2 optical switch pair, and further the same as the waveguide expansion section for constructing the crossed waveguides in each switch element. The point that the waveguide expansion unit 30 is collectively configured is significantly different from the conventional configuration.

In the path-independent configuration, in each optical switch element, the optical switch element in which the arrangement of the input line optical waveguides 11a-11b and the output line optical waveguides 12a-12b is positive and the optical switch element in the upside-down inverted downward direction is arranged. , Arranged in an alternating checkered pattern. Therefore, when the double gate type optical switch element is used as the 2 × 2 optical switch element, the input line optical waveguides 11a-11b, 21 in the double gate type optical switch element are used.
a-21b and output line optical waveguides 12a-12b, 22a-2
The crossed waveguides 19 and 29 of 2b are arranged at positions close to each other in the waveguide type modified 2 × 2 optical switch pair configured as a pair as described above. Therefore, the input line optical waveguide 11a-1 generated between the switch stages on the output end side of the switch element
Output line optical waveguide 1 generated between the cross waveguide 31a of 1b and 21a-21b and the switch stage on the input end side of the switch element
The crossed waveguides 32b of 2a-12b and 22a-22b can be incorporated into a waveguide-type modified 2 × 2 optical switch pair, and further, in the above-mentioned waveguide-type modified 2 × 2 optical switch pair. Input line optical waveguides 11a-11b, 21a-21b
And the output line optical waveguides 12a-12b, 22a-22b are arranged in the vicinity of the crossed waveguides 19, 29, so that these four crossed waveguides 19, 29, 31a, 32b are collectively expanded into one waveguide. The unit 30 can be used.

As described above, the waveguide expansion parts 51a, 51b, 5 generated between the switch stages which are generated in a path-independent manner.
By constructing the 1c crossed waveguides 31a and 31b in a paired waveguide-type modified 2 × 2 optical switch pair, the crossed waveguides 51a of the crossed waveguides are formed between the switch stages. , 51b and 51c are not required to be newly provided, the effect of halving the block due to the introduction of the path-independent type is sufficiently brought out, and the circuit length can be greatly shortened.

Further, the waveguide development portions of the cross waveguides 31a and 32b generated between the switch stages and the waveguide development portions of the cross waveguides 19 and 29 in the double gate type optical switch element are collectively described. By laying out the waveguides in the same waveguide expansion portion 30, the circuit size including the size in the lateral direction perpendicular to the waveguide direction can be reduced.

As shown in FIGS. 1B and 1C, the 4 × 4 matrix optical switch of Embodiment 1 has a silica-based waveguide 2 on a silicon substrate 1 having a thickness of 1 mm and a diameter of 6 inches. Was manufactured by a combination of a deposition technique of a silica-based glass film utilizing a hydrolysis reaction of a raw material gas such as SiCl ₄ and GeCl ₄ and a reactive ion etching technique, and a thin film heater was manufactured by a vacuum vapor deposition method and a chemical etching.

Silica-based input line waveguide cores 11a-11b,
21a-21b, silica-based output line waveguide core 12a-12
b, 22a-22b are silica-based bypass waveguide cores 13a-
The cross-sectional dimensions of the cores such as 13b and 23a-23b are 6 μm square, and the relative refractive index difference between the core and the clad is 0.75%. The thin film heater has a thickness of 0.1 μm and a width of 4
The length is 0 μm and the length is 3 mm.

The 2 × 2 optical switch element used in the first embodiment is basically composed of a straight waveguide and a curved waveguide having a radius of about 5 mm. Crossed waveguides 31a, 31b, 19,
The crossing angles θ and θ ′ of 29 were around 30 degrees. Two directional couplers 1 forming a Mach-Zehnder interferometer circuit
4a, 14b, 15a, 15b, 24a, 24b, 25
The effective optical path length difference between the two waveguides connecting a and 25b was accurately set to 0.775 μm, which is half the signal light wavelength of 1.55 μm. The actual waveguide length difference on the mask pattern was set to 0.775 μm / 1.45 = 0.534 μm in consideration of the refractive index of silica glass being 1.45.

At this time, the size of the waveguide-type modified 2 × 2 optical switch pair in which two 2 × 2 optical switch elements are combined is W 0.9 mm × L 16.3 mm, and each 2 × 2 optical switch element is Size is W 0.45mm × L1
It became 6.3 mm. When the crossed waveguides between the switch stages are not formed by the same waveguide development part as the crossed waveguides in the switch element, 2 × including the waveguide development part of the crossed waveguides between the switch stages is included. The size of one two-optical switch element was W0.5 mm × L20.1 mm.

Therefore, by adopting the layout structure of the present invention, the circuit length could be shortened by about 20%. The chip size of the entire 4x4 matrix optical switch including the heater driving electrodes is 10x90mm.
Met.

The chip in which this 4 × 4 matrix optical switch is manufactured is cut out by dicing, a heat dissipation plate is provided under the silicon substrate, and a single mode fiber array is connected to the input / output waveguide to form a thin film heater. Was connected to the power supply lead, and a 4 × 4 matrix optical switch module was completed.

The 4 × 4 switch operation was confirmed by appropriately selecting the thin film heater to be supplied with power. The power consumption of each thin film heater required for the switch operation was about 0.45 W. Each optical switch element drives two thin film heaters for operation, and the maximum number of optical switch elements operating at the same time is 4 so total power consumption is 0.45W maximum.
It was about × 2 × 4 = 3.6W.

The extinction ratio of the matrix optical switch as a whole is such that the coupling ratio of the directional coupler is 50% ± 1 due to manufacturing error.
Even with a very large deviation of about 5%, a very excellent value of about 50 dB was obtained. The loss value as a matrix optical switch was 1 to 2 dB including the optical fiber connection loss, and a very low loss value was obtained.

FIG. 5 shows a first embodiment of an N × N matrix optical switch which is the same as the 4 × 4 matrix optical switch and is the object of the present invention (particularly, one example of N = 2M, M: a positive integer).
It is a figure which shows schematic structure of the 6x6 matrix optical switch as another Example.

The introduction of the optical waveguide and the manufacturing method of this embodiment are basically the same as those of the above-mentioned 4 × 4 matrix optical switch, except that the scale N of the matrix optical switch is different. In FIG. 5, SLU is an area in which the waveguide type modified 2 × 2 optical switch pair of FIG. 1 is arranged, and SW1 is a conventional double gate type 2 × 2 optical switch element arranged in the same direction vertically. Area, SW2
Is an area where the conventional double gate type 2 × 2 optical switch elements are arranged upside down.

Also in this embodiment, the circuit size including the size in the lateral direction perpendicular to the waveguide direction can be reduced as in the 4 × 4 matrix optical switch, and the heater driving electrodes and the like are included. The chip size of the entire 4 × 4 matrix optical switch was 12 mm × 120 mm. As for the device characteristics, the total power consumption was about 5.4 W, the extinction ratio was about 50 dB, and the insertion loss value was about 2 dB including the optical fiber connection loss.

(Second Embodiment) FIG. 6 shows N × N according to the present invention.
Another embodiment of the matrix optical switch (particularly N = 2M-1)
FIG. 6 is a diagram showing a schematic configuration of a 5 × 5 matrix optical switch of Embodiment 2 as an example (M: positive integer).

The outline of the optical waveguide and the manufacturing method of the second embodiment are basically the same as those of the 4 × 4 matrix optical switch of the first embodiment. In the first embodiment, the scale N of the matrix optical switch is an even number, but in the second embodiment
The difference is that the scale N of the matrix optical switch is odd.

In FIG. 6, SLU is an area in which the waveguide type modified 2 × 2 optical switch pair of FIG. 1 is arranged,
SW1 is a region in which the conventional double-gate type 2 × 2 optical switch elements are arranged in the same direction up and down, and SW2 is a region in which the conventional double-gate type 2 × 2 optical switch elements are arranged upside down. It is the area where

As described above, in the first embodiment, the switch stage in which only the waveguide modified 2 × 2 optical switch pair is arranged, the waveguide modified 2 × 2 optical switch pair and the conventional double gate type 2 × While the matrix optical switch is configured by two types of switch stages in which two two optical switch elements (a forward direction arrangement and a reverse direction arrangement) are arranged, in the second embodiment, the waveguide deformation 2 × Two optical switch pairs and a switch stage in which one conventional double-gate type 2 × 2 optical switch element (forward direction arrangement) is arranged, and a waveguide modified 2 × 2 optical switch pair and a reverse direction The matrix optical switch is different from that of the first embodiment in the configuration of two types of switch stages, in which one conventional double-gate type 2 × 2 optical switch element (reverse direction arrangement) is arranged.

Also in the second embodiment, the first embodiment
Similarly, the circuit size can be reduced including the size in the lateral direction perpendicular to the waveguide direction, and the chip size of the entire 5 × 5 matrix optical switch including the heater driving electrodes and the like is 11 mm × 105 mm. Met. The device characteristics are total power consumption of about 4.5 W, extinction ratio of about 50 dB, and insertion loss of 2 dB including optical fiber connection loss.
It was about.

(Embodiment 3) FIG. 7A shows an arrangement of the entire configuration of an 8 × 8 matrix optical switch according to Embodiment 3 of the present invention. In FIG. 7A, 70a to 70e are 1
This is a waveguide bundle consisting of six waveguide bundles 70a to 7
Optical switch blocks # 1, # 2, and 8 at 8 points on the way of 0e
..., # 8 is arranged. The characteristic of the 8 × 8 matrix optical switch of the second embodiment shown in FIG. 7A is that it is between the input terminal and the optical switch stage # 1, between the optical switch stages # 2 and # 3,
Between # 4 and # 5, between # 6 and # 7, and optical switch stage #
8 and the output end are connected by waveguide bundles 70b, 70c, 70d each having a bend of 90 to 180 degrees. In other words, the curved waveguide bundle 70
b, 70c, 70d to the curved waveguide bundles 70b, 7
In consideration of suppressing the increase in circuit length due to 0c and 70d, eight optical switch stages # 1, # 2, ...
The feature is that # 8 is arranged on a limited substrate size.

FIGS. 7B and 7C are layout diagrams of 2 × 2 optical switch elements in each of the optical switch stages 1, # 2, ..., # 8. In FIGS. 7B and 7C, the SLU
Is a region where the waveguide type modified 2 × 2 optical switch pair of FIG. 1 is arranged, and SW1 is a conventional double gate type 2 × 2.
The optical switch elements are arranged in the same direction up and down, and SW2 is the area in which the conventional double gate type 2 × 2 optical switch elements are arranged upside down. Figure 7
In (a), optical switch stages # 1, # 3, # 5, # 7.
Are arranged in the optical switch blocks # 2, # 4, # 6, and # 8, and the optical switch stages having the structure shown in FIG. 7C are arranged in the optical switch blocks # 2, # 4, # 6, and # 8. Has been done.

In the arrangement where the input terminal and the output terminal face each other,
The layout of the optical switch stages 1, # 2, ..., # 8 of the third embodiment has the shortest circuit length (29 cm). By the way, when a normal matrix optical switch by the connection as shown in FIG. 11 of the related art is manufactured on a 4-inch silicon substrate by using the double gate type 2 × 2 optical switch element (the circuit layout is the same as that of the fourth embodiment). The circuit length (optical path length) of the layout similar to (1) was about 60 cm. Therefore, the layout of the third embodiment was able to reduce the circuit length to half or less.

The 8 × 8 matrix optical switch of the third embodiment was manufactured on a silicon substrate having a thickness of 1 mm and a diameter of 4 inches. The chip size was 68 mm × 68 mm. Other circuit concepts and circuit / module manufacturing methods are the same as those in the first embodiment.

8 × 8 switch operation was confirmed by appropriately selecting the thin film heater to be supplied with power. The power consumption of each thin film heater required for the switch operation was about 0.45 W. Each optical switch element drives two thin film heaters for operation, and the maximum number of optical switch elements that operate at the same time (ON) is 8. Therefore, the total power consumption is 0.45W × 2 × 8 maximum. = About 7.2W.

The extinction ratio of the matrix optical switch as a whole was about 50 dB, which was a very excellent value. The loss value of the matrix optical switch as a whole was 4 to 5 dB including the optical fiber connection loss, and a very low loss value was obtained. By the way, in the case of the above-mentioned conventional example, the loss value was 7 to 8 dB including the optical fiber connection loss.
In the circuit of Embodiment 2, the loss value is reduced by 40% or more.

In the third embodiment, in order to make the input terminal and the output terminal face each other, between the optical switch stage # 1 and the input terminal,
A curved waveguide bundle is used between the optical switch stage # 8 and the output terminal, but a linear waveguide bundle is used between the optical switch stage # 1 and the input terminal and between the optical switch block # 8 and the output terminal. Of course, it does not matter if the ends are provided on the same chip side.

(Fourth Embodiment) FIG. 8 shows the overall arrangement of an 8 × 8 matrix optical switch as a fourth embodiment of the matrix optical switch of the present invention. The fourth embodiment is basically the same as the third embodiment except that the overall arrangement of the optical switch block is different. The fourth embodiment is characterized in that eight optical switch stages are arranged on a limited substrate size, giving the highest priority to minimizing the chip size by appropriately using a bent waveguide bundle. This is different from the third embodiment.

The 8 × 8 matrix optical switch of Embodiment 4 was manufactured on a silicon substrate having a thickness of 1 mm and a diameter of 4 inches. The chip size was 65 × 55 mm.

8 × 8 switch operation was confirmed by appropriately selecting the thin film heater to be supplied with power. The power consumption of each thin film heater required for the switch operation was about 0.45 W. Each optical switch element drives two thin film heaters for operation, and the maximum number of optical switch elements that operate at the same time is 8 so total power consumption is 0.45W maximum.
It was about × 2 × 8 = 7.2W.

The extinction ratio of the matrix optical switch as a whole was about 50 dB, which was a very excellent value. The loss value as a matrix optical switch was 5 to 6 dB including the optical fiber connection loss, and a very low loss value was obtained.

In the first to fourth embodiments of the present invention, the crossing angle in the crossing waveguide is set to 30 degrees. Next, the setting of this crossing angle will be considered.

Although it varies depending on the relative refractive index difference of the optical waveguides used and the core size of the waveguides, in general, if the crossing angle is 20 degrees or more, the crosstalk between the two optical waveguides depends on the straightness of light. It can be ignored for practical purposes. In the case of the crossing angle of 30 degrees adopted in the above embodiment, the crosstalk is −60 dB.
The loss in the cross waveguide is 0.1.
It is as low as dB. Generally, the crosstalk and the loss of the crossed waveguides are improved as the crossing angle approaches 90 degrees. However, when the crossing angle is increased, the occupied area of the waveguide expansion portion before and after the crossing waveguides increases and the size of the optical switch element increases. Therefore, it is desirable to make the determination in consideration of the required performance of the matrix optical switch and the allowable bending radius of the optical waveguide.

In the first to fourth embodiments, the case where the signal light wavelength is 1.55 μm is dealt with, but the layout of the present invention can be applied to other wavelengths such as 1.3 μm wavelength.

Although the matrix optical switches based on silica glass on the silicon substrate are described in the first to fourth embodiments, other materials such as Mach-Zehnder interferometer circuit type optical switch elements can be used. The present invention can also be applied to polymer optical waveguides, ion diffusion waveguides, and lithium niobate optical waveguides provided with an optical phase shifter using the electro-optic effect.

In particular, the polymer optical waveguide has a thermo-optical effect which is about 10 times as large as that of the silica-based waveguide.
It is possible to easily construct a 1 × 2 optical switch or a 2 × 1 optical switch by the Y branch waveguide as shown in (b), (c), and (d). In this case, the waveguide type deformation 2 × 2 of FIG.
As shown in FIG. 2 (a), the switch pair is set to 1 × 2 described above.
It can be configured by an optical switch or a 2 × 1 optical switch.

(A) is a plan view of a waveguide type modified 2 × 2 optical switch pair including a Y-branch optical waveguide, (b) is an enlarged plan view of the Y-branch optical waveguide, and (c) is A shown in (b). -A 'is a sectional view taken along the line, and (d) is a sectional view taken along the line BB' shown in (b). In FIG. 2, 1 is a silicon substrate, 45 is a polymer clad layer, 40 is a Y-branch optical waveguide, 41, 42 and 43 are polymer optical waveguide cores, 4
Reference numerals 4a and 44b are thin film heaters, and 30 is a waveguide development portion.

Further, since the lithium niobate optical waveguide has a large electro-optic effect, it is well known that the directions shown in FIGS. 3 (b), 3 (c) and 3 (d) are obtained. The 1 × 2 optical switch and the 2 × 1 optical switch can be easily configured by the sex coupler. In this case, the waveguide type modified 2 × 2 switch pair of FIG. 1 can be configured by the 1 × 2 optical switch or the 2 × 1 optical switch as shown in FIG.

(A) is a plan view of a waveguide type modified 2 × 2 optical switch pair including a directional coupler, (b) is an enlarged plan view of the directional coupler, and (c) is A shown in (b). -A 'is a sectional view taken along the line, and (d) is a sectional view taken along the line BB' shown in (b). In FIG. 3, 60 is a directional coupler, 61 and 62 are lithium niobate optical waveguide cores, 63a and 63b are voltage applying electrodes, 64 is an insulating film, and 65
Is a lithium niobate substrate plate, and 30 is a waveguide development part.

The inventions made by the present inventor are as follows.
Although specifically described based on the embodiment, the present invention
It is needless to say that the present invention is not limited to the above embodiment, and various changes can be made without departing from the scope of the invention.

[0096]

The effects obtained by typical aspects of the invention disclosed in the present application will be briefly described as follows.

(1) The circuit length (optical path length) can be significantly reduced as compared with the matrix switch having the conventional structure, while using the double-gate type optical switch element capable of obtaining a high extinction ratio, and Therefore, the insertion loss can be reduced.

(2) The light guide type modified 2 × 2 optical switch of the present invention is not only a basic constituent element of the light guide type matrix optical switch, but also used as two continuous light guide type 2 × 2 optical switches. Also in this case, the size can be made smaller than the conventional parallel arrangement of the light guide type 2 × 2 optical switches.

(3) It is extremely effective in putting a matrix optical switch with high extinction ratio and insertion loss into practical use.

[Brief description of drawings]

1A and 1B are an enlarged plan layout view and a cross-sectional view when a waveguide type modified 2 × 2 optical switch according to a first embodiment of the present invention is configured by a Mach-Zehnder interferometer.

2A and 2B are an enlarged plan layout view and a cross-sectional view when the waveguide type modified 2 × 2 optical switch of the first embodiment is configured with a Y-branch optical waveguide.

3A and 3B are an enlarged plan view and a cross-sectional view in the case where the waveguide type modified 2 × 2 optical switch of the first embodiment is configured by a directional coupler.

FIG. 4 is an overall plan layout view of the waveguide type 4 × 4 matrix optical switch of the first embodiment.

FIG. 5 is an overall plan layout view of the waveguide type 6 × 6 matrix optical switch of the first embodiment.

FIG. 6 is an overall plan layout view of a waveguide type 5 × 5 matrix optical switch according to a second embodiment of the present invention.

FIG. 7 is an overall plan layout view of a waveguide type 8 × 8 matrix optical switch according to a third embodiment of the present invention.

FIG. 8 is an overall plan layout view of a waveguide type 8 × 8 matrix optical switch according to a fourth embodiment of the present invention.

FIG. 9 is a conceptual diagram showing the configuration of a 4 × 4 matrix optical switch.

FIG. 10 is an overall plan layout view of a conventional thermo-optical 4 × 4 matrix optical switch.

FIG. 11 is an enlarged plan view of a conventional double-gate type 2 × 2 optical switch element, its cross-sectional view, and a plan view in which two of them are arranged in parallel.

FIG. 12 is an overall plan layout view of a conventional 4 × 4 waveguide type matrix optical switch having a path-independent structure.

FIG. 13 is a conceptual diagram for explaining that the target optical switch of the present invention is a switch having a matrix configuration.

FIG. 14 is a diagram showing a configuration example of a conventional 2 × 2 optical switch.

[Explanation of symbols]

1 ... Silicon substrate, 2 ... Quartz glass clad layer, 11
a-11b, 21a-21b ... Silica-based input line waveguide core,
12a-12b, 22a-22b ... Silica-based output line waveguide core, 13a-13b, 23a-23b ... Silica-based bypass waveguide core, 14a, 14b, 15a, 15b, 24a,
24b, 25a, 25b ... Directional coupler, 16a, 16
b, 17a, 17b, 26a, 26b, 27a, 27b
... thin-film heater (phase shifter), 18a, 28a ... first Mach-Zehnder interferometer circuit, 18b, 28b ... second Mach-Zehnder interferometer circuit, 19, 29 ... Input line optical waveguide in double-gate optical switch element Cross waveguide of output line optical waveguide, 31a ... Cross waveguide of input line optical waveguide generated between switch blocks on the output end side of the switch element, 32
b ... Crossed waveguides of output line optical waveguides generated between the switch blocks on the input end side of the switch element, 30 ... Waveguide expanding portion, 40 ... Y branch optical waveguide, 41, 42, 43 ... Polymer optical waveguide, 44a , 44b ... Thin film heater (phase shifter), 1a-1d, 2a-2d, ..., 3a-3d ... Input line optical waveguide, 1c-1b, 2c-2b, ..., 3c-3b ... Output line optical waveguide, S11, , S44 ... 2 × 2 optical switch element, SLU ... Waveguide type modified 2 × 2 optical switch pair, # 1, # 2, ..., # 8 ... Optical switch stage, 51a,
51b, 51c ... Waveguide expanding portions for forming crossed waveguides between switch stages, SW1, SW2 ... Conventional double gate type optical switch element, 60 ... Directional coupler, 61, 62
... Lithium niobate optical waveguide core, 63a, 63b ...
Voltage applying electrodes, 64 ... Insulating film, 65 ... Lithium niobate substrate, 70a-70e, 71a-71j ... Optical waveguide bundle,
70b, ..., 70d, 71b, ..., 71i ... Curved waveguide bundle.

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[Procedure amendment]

[Submission date] August 6, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

Title: Modified waveguide 2 × 2 optical switch and waveguide matrix optical switch

[Claims]

4. (2M-1) (M is a positive integer of 2 or more)
A waveguide-type matrix optical switch including at least two input line optical waveguides and (2M-1) output line optical waveguides, wherein the waveguide type 2 includes one input line optical waveguide and one output line optical waveguide. × with 2 optical switches and waveguide shape modification 2 × 2 optical <br/> switch (2M-1) is a switch stage of the stage, the odd-numbered switching stage the waveguide 2 × 2 optical switch and (M-1) pieces of the waveguide-type deformation the 2 × 2 optical switch
Is constructed by arranging in parallel the switch in this order, the even-numbered switch stage (M-1) pieces of the waveguide-type deformation the 2 × 2 optical Sui <br/> pitch and the waveguide 2 × 2 optical The switches are arranged in parallel in this order, and a total of 2 (2M-1) input line optical waveguides and (2M-1) output line optical waveguides are provided between the stages. ) A waveguide-type matrix optical switch characterized by connecting two optical waveguides without crossing each other.

5. (2M-1) (M is a positive integer of 2 or more)
A waveguide-type matrix optical switch including at least two input line optical waveguides and (2M-1) output line optical waveguides, wherein the waveguide type 2 includes one input line optical waveguide and one output line optical waveguide. × with 2 optical switches and waveguide shape modification 2 × 2 optical <br/> switch (2M-1) is a switch stage of the stage, the odd-numbered switch stage (M-1) pieces of the electrically The waveguide type modified 2 × 2 optical switch and the waveguide type 2 × 2 optical switch are arranged in parallel in this order, and the even-numbered switch stages are the waveguide type 2 × 2 optical switch and (M-1). It is constructed by arranging a number of said waveguide modification 2 × 2 optical switch in parallel in this order, wherein said the (2M-1) present in the input line waveguide between the respective stages (2M-1) present A total of 2 (2M-1) optical waveguides of the output line optical waveguide are connected without crossing. Waveguide type matrix optical switch to.

Wherein said waveguide-type deformation the 2 × 2 optical switch,
The waveguide-type modified optical switch according to claim 1, wherein the waveguide-type matrix optical switch according to any one of claims 2 to 4.

7. The waveguide type 2 × 2 optical switch is composed of one input line optical waveguide, one output line optical waveguide and one bypass optical waveguide, and an input portion is the input line optical waveguide.
A 1 × 2 optical switch having an output section as the input line optical waveguide and the bypass optical waveguide, and a 2 × 1 optical switch having an input section as the output line optical waveguide and the bypass optical waveguide and an output section as the output line optical waveguide is a switch, the 1 × 2 optical switch and the 2 × 1 waveguide 2 × said output line optical waveguide and the input line waveguide between the optical switch intersect
The waveguide type matrix optical switch according to any one of claims 2 to 5, which is a two-optical switch.

Wherein said 1 × 2 optical switches and the 2 × 1 optical switch, the two optical waveguides in close proximity in two places constitute the two directional couplers, and, with the switch driving terminal The waveguide type matrix optical switch according to claim 6, which is a Mach-Zehnder interferometer circuit.

Wherein said 1 × 2 optical switches and the 2 × 1 optical switch, a waveguide-type matrix optical switch as set forth in claim 6, characterized in that the Y-branch switch having a switch driving terminal.

Wherein said 1 × 2 optical switches and the 2 × 1 optical switch, wherein the two optical waveguides are close at one position, and characterized in that it is a directional coupler having a switch driving terminal Item 6. A waveguide type matrix optical switch according to item 6.

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide type optical switch used in the field of optical communication and the like, and in particular, it is resistant to fabrication errors and has an excellent extinction ratio, and has a short optical path length (circuit length).
Waveguide type deformation that can be compactly integrated on a single substrate 2 ×
Applied to the layout structure of a waveguide type matrix optical switch using 2 optical switch及 Bikore a technique effectively.

[0002]

2. Description of the Related Art In recent years, optical fiber, light-receiving elements and light-emitting elements have become more and more popular due to cost reduction and optical communication in communication networks is becoming widespread. Almost all communication lines in relay networks have been replaced by optical fiber communication. There is. Further, the optical communication network is changed from point-to-point optical communication that individually connects nodes to optical communication network of a network structure in which a plurality of nodes including an access network are connected as optical signals without being converted into electric signals. It is time to develop. There is an urgent need to develop various optical components such as optical branching / coupling devices, optical multiplexer / demultiplexers, and optical switches. Among them, optical switches (especially matrix optical switches that can be strictly non-blocking switches) are used as components used for switching optical fiber lines freely according to demand, and for switching to secure detours in the event of line failure. The need is growing.

A bulk type, a waveguide type, etc. have been proposed as an implementation form of the optical switch. The bulk type is composed of movable prisms and lenses as constituent elements, and has the advantage of less wavelength dependence and relatively low loss, but it is not suitable for mass production because the assembly adjustment process is complicated. There is a problem that it is expensive, and it has not spread widely. The waveguide type is based on an optical waveguide on a flat substrate that is manufactured using microfabrication technology using photolithography and various etchings, and is excellent in terms of mass productivity and miniaturization. Is expected as the optical switch of.

[0004] Further, conventionally, attempts have been made to fabricate a matrix optical switch by using optical waveguides of various materials. Among them, a silica optical waveguide fabricated on a silicon substrate is used for heat generation. The thermo-optical matrix optical switch utilizing the optical effect is excellent in stability and compatibility with optical fibers, and is expected as the most promising means for realizing a practical matrix optical switch.

FIG. 9A shows N × N which is the object of the present invention.
It is a structure conceptual diagram of a 4x4 matrix optical switch as an example of a matrix optical switch. This 4 × 4 matrix optical switch has four input line optical waveguides 1a-1d and 2a-
2d, 3a-3d, 4a-4d and four output line optical waveguides 1
c-1b, 2c-2b, 3c-3b, 4c-4b is 4 × 4 =
It has a structure that intersects at 16 points. This intersection 2 × 2 optical switch elements S11 ~ as the minimum unit of the optical switch
S44 is arranged. Each of these optical switch elements is switched on / off (ON / OFF) to switch from the cross state shown in FIG. 9B to the bar state shown in FIG. 9C. Such a matrix optical switch has a strictly non-blocking configuration, and in order to connect an arbitrary input line optical waveguide and output line optical waveguide, this input line optical waveguide and this output line optical waveguide intersect. You only have to connect one intersection.

FIG. 10 shows an entire conventional thermo-optical 4 × 4 waveguide type matrix optical switch which is manufactured by using a silica single mode waveguide corresponding to the 4 × 4 matrix optical switch of FIG. FIG. 11 (a) is an enlarged plan view of a 2 × 2 switch elements double gate type 2 × 2 optical switch elements using each intersection difference <br/> point (JP-A-6-51354), 11 (b) and 11 (c) are C of FIG. 11 (a).
FIG. 6 is a cross-sectional view taken along the line C ′ and the line DD ′.

These waveguides are formed on a silicon substrate by a known combination of the flame hydrolysis reaction deposition method and the reactive ion etching technique.

As shown in FIG. 11 (a), the optical switch element includes the input line optical waveguides 11a-11b and the output line optical waveguide 1 which intersect each other at an angle θ where crosstalk can be ignored.
2a-12b plus bypass waveguides 13a-13b 3
It is composed of a book optical waveguide and has two Mach-Zehnder interferometer circuits 18a and 18b.

That is, the input line optical waveguides 11a-11b
And a part of the bypass waveguides 13a-13b are close to each other at two locations, form directional couplers 14a and 15a, constitute a first Mach-Zehnder interferometer circuit, and output the bypass waveguides 13a-13b. Part of the line optical waveguides 12a-12b are close to each other at two locations to form the directional couplers 14b and 15b, and form a second Mach-Zehnder interferometer circuit.

The optical coupling rate of these directional couplers is set to 50% at the signal light wavelength. In these Mach-Zehnder interferometer circuits, the difference in the optical path lengths of the two waveguides connecting the two directional couplers is accurately set to one-half the signal wavelength in the OFF state. At least one of the two waveguides is loaded with a thin film heater for changing the optical path length by utilizing the so-called thermo-optic effect.

In the OFF state (non-energization of the thin film heater), in the first Mach-Zehnder interferometer circuit, the two optical waveguides that connect the two directional couplers are halved of the signal wavelength. Since the optical path lengths are different, if the coupling ratios of the two directional couplers are the same, regardless of the absolute value of the coupling ratios, the input line optical waveguide 11a-1 can be produced by the known interference principle.
The signal light transmitted to 1b is apparently the bypass waveguide 13a-
100% input line optical waveguide 11a without being transmitted to 13b
Since only -11b is propagated, when viewed as a 2 × 2 optical switch element as a whole, the signal light passes through the optical switch element with a 100% cross path.

Even if the first Mach-Zehnder interferometer circuit leaks signal light into the bypass waveguides 13a-13b,
This leakage signal light apparently propagates only through the bypass waveguides 13a-13b in the second Mach-Zehnder interferometer circuit and the same principle as the first Mach-Zehnder interferometer circuit, and then propagates to the output line optical waveguides 12a-12b. Is not transmitted, there is almost no optical crosstalk into the bar path when viewed as a 2 × 2 optical switch element as a whole.

In these two Mach-Zehnder interferometers, the thermo-optical phase shifter provided on the waveguide connecting the two directional couplers is operated (the thin film heater is energized), and the optical path equivalent to the half is obtained. When the length difference is canceled and the state is turned on, the signal light transmitted to the input line optical waveguide 11a in the first Mach-Zehnder interferometer circuit is bypassed by the bypass waveguide 13a-1.
3b, and further to the output line optical waveguide 12b by the second Mach-Zehnder interferometer circuit, the state of the optical switch element can be switched to the bar path.

As described above, the double gate type 2 × 2 optical switch element is a two-stage Mach-Zehnder interferometer circuit 18
Since the optical crosstalk is controlled by the double barrier consisting of a and 18b, it is possible to realize a 2x2 optical switch element with an extremely high extinction ratio, and it is expected from the viewpoint of expanding the range of application of the matrix optical switch to the system. ing.

FIG. 14 is a diagram showing another conventional 2 × 2 waveguide type optical switch, which is an example of the waveguide type 2 × 2 optical switch using only one Mach-Zehnder interferometer circuit. .

On the other hand, in an N × N strictly non-blocking waveguide type optical switch constructed by connecting N ² 2 × 2 waveguide type optical switch elements, the connection as shown in FIG. As a configuration in which the number of switch stages is smaller than that of a normal matrix optical switch, FIG.
There is known a connection configuration (path independent configuration) as shown in (Japanese Patent Publication No. 6-66982). This path-independent type configuration basically has the lower output terminal of the optical switch element of the i-th row and the j-th column (where i and j are integers and 1 <i <N, j <N) A matrix optical switch is configured by connecting the upper input terminal of the optical switch element at i + 1th row and j + 1th column and connecting the upper output terminal to the lower input terminal of the optical switch element at i−1th row and j + 1th column. .

At first glance, this path-independent type optical switch seems to be completely different in logic configuration from the ordinary matrix type optical switch, but in order to connect an arbitrary input waveguide and an arbitrary output waveguide, The logical structure that can be connected by driving only one 2 × 2 waveguide type optical switch element is the same as a normal matrix optical switch.

It will be described below that this logical configuration is the same as the conventional one. FIG. 13A is a diagram showing a so-called conventional connection configuration in, for example, a 4 × 4 matrix switch. In this connection configuration, an arbitrary input line optical waveguide and an arbitrary output line optical waveguide always have one intersection (for example, 1a-1d and 1c-1b have S11), so strict non-blocking operation is possible, and In order to connect an arbitrary input line optical waveguide and output line optical waveguide, it is sufficient to connect only one intersection where this input line optical waveguide and this output line optical waveguide intersect. That is, if the principle that an arbitrary input line optical waveguide and an arbitrary output line optical waveguide always have one intersection, the logical configuration does not change even if the arrangement of switch elements is changed from the above configuration.

First, the input line optical waveguide is divided into two parts (for example, 1a-1d is divided into 1a-1e and 1f-1d) and arranged as shown in FIG. 13B. And an output line optical waveguide are newly crossed, S12, S13, S14, S23, S24, S34
The switch elements of can be moved to this new intersection. Then, in order to connect the two divided input line waveguides, a cylinder as shown in FIG. 13C is considered, and when the circuits are arranged so that these waveguides are attached to this surface, this division is performed. The input line waveguide can be connected smoothly.

Actually, since the circuit is not manufactured on the cylinder, as shown in FIG. 13D, the circuit on the plane is arranged by two-dimensionally projecting the arrangement on the cylinder onto the plane. To be realized. In this configuration, the waveguides connecting the respective switch elements intersect each other, and although the appearance is completely different from that of FIG. 13A, the arbitrary input line optical waveguide and the arbitrary output line optical waveguide always have one intersection. The principle of possessing has not changed and is the same as before.

Here, although the description has been made specifically for the 4 × 4 matrix switch, by applying the same idea, this configuration can be applied to the N × N matrix switch.
Just like a normal matrix optical switch, you can connect any input waveguide to any output waveguide by using only one 2
It can be easily understood that the logical configuration is such that the waveguide optical switch element of × 2 can be connected by driving.

In the N × N strictly non-blocking waveguide type optical switch, the number of switch stages in which 2 × 2 waveguide type optical switches are combined is 2N− in a normal matrix configuration.
While one stage is required, only N stages are required in the path-independent configuration. Therefore, in the path-independent configuration, the number of switch stages can be reduced to about half as compared with the normal matrix configuration, and thus the circuit length (optical path length) can be expected to be significantly reduced. In addition, reduction in loss can be expected by shortening the circuit length (optical path length).

[0023]

SUMMARY OF THE INVENTION The present inventor has found the following problems as a result of studying the above conventional technology.

In the conventional path-independent structure, in the waveguide connecting the switch elements among the number of switch stages , an intersection between the waveguides, which is not the matrix structure, is newly generated. Therefore, in order to suppress the loss at this intersection and the crosstalk between the waveguides, it is necessary to intersect these two waveguides at a certain crossing angle. Therefore, it is mainly composed of curved waveguides before and after this intersection. Waveguide expansion part 5
It was necessary to provide 1a, 51b, 51c.

Therefore, even if the number of switch stages is reduced from the normal matrix type configuration to the path-independent type configuration, the waveguide expanding section which increases the circuit length (optical path length) is required, and therefore the switch is required. There is a problem in that the effect of shortening the circuit length (optical path length) by reducing the number of stages cannot be sufficiently obtained.

An object of the present invention is to use an optical switch element having a constitution capable of obtaining the above-mentioned high extinction ratio for each optical switch element, and to reduce the circuit length (optical path length) significantly. An object of the present invention is to provide a technique capable of providing an optical waveguide layout that suppresses the influence of the increase in the circuit length (optical path length) caused by the waveguide expansion portion of the crossed waveguide that occurs in the path-independent configuration.

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

[0028]

The outline of the representative one of the inventions disclosed in the present application will be briefly described as follows.

[0029] (1) two input lines waveguide, a two output lines optical waveguide and two bypass waveguide waveguide type deformation the 2 × 2 optical switch consisting of an input first A first 1 × 2 optical switch having an input line optical waveguide and an output unit as the first input line optical waveguide and a first bypass optical waveguide, and an input unit as a second input line optical waveguide and an output unit A second 1 × 2 optical switch that serves as a second input line optical waveguide and a second bypass optical waveguide, and a first output line optical waveguide and a second bypass optical waveguide as an input section and the output section as the first section. A second 2 × 1 optical switch as an output line optical waveguide, and an input unit as the second output line optical waveguide and the first bypass optical waveguide, and an output unit as the second output line optical waveguide. Second
The second input line waveguide and the second input line waveguide after the first 1 × 2 optical switch is configured. The second input line waveguide intersects with the waveguide in this order, and after the second input line waveguide constitutes the second 1 × 2 optical switch, it is connected to the first output line waveguide and the first input line waveguide. Crossing in this order, the first output line waveguide and the second output line waveguide and the second output line waveguide are formed before forming the first 2 × 1 optical switch.
Crossing the input line waveguide in this order, and the second output line waveguide before forming the second 2 × 1 optical switch,
The first output line waveguide and the first input line waveguide are crossed in this order, and a total of these four crossings are the first 1 × 2 optical switch and the second 1 × 2 optical switch. And a waveguide type modification 2 × located near the center of a region surrounded by the first 2 × 1 optical switch and the second 2 × 1 optical switch.
It is a two-optical switch.

(2) A waveguide type matrix optical switch including at least 2M (M is a positive integer) input line optical waveguides and 2M output line optical waveguides, each having one input line optical waveguide. A waveguide type 2 × 2 optical switch comprising an output line optical waveguide and a waveguide type modified 2 × 2 optical switch,
M pieces of the waveguide type modified 2 × 2 optical switches are arranged in parallel to form a (2k−1) th stage (k is an integer of 1 or more and M or less), and the waveguide type 2 × 2 optical switch, ( M-1) number of the waveguide type modified 2 × 2 optical switches, the waveguide type 2 ×
Two optical switches are arranged in parallel in this order to form a 2k-th stage, and a total of 4M optical waveguides of the 2M input-line optical waveguides and the 2M output-line optical waveguides are crossed between the respective stages. It is a waveguide type matrix optical switch that is connected without performing the above.

(3) 2M (M is a positive integer) input light beams
Conductor including at least a waveguide and 2M output line optical waveguides
Waveguide-type matrix optical switch with one input each
Waveguide type 2 × 2 light consisting of line optical waveguide and output line optical waveguide
A switch and a waveguide-type modified 2 × 2 optical switch,
M pieces of the waveguide type modified 2 × 2 optical switches are arranged in parallel.
The second k-th stage (k is an integer of 1 or more and M or less), and
Waveguide type 2 × 2 optical switch, (M-1) waveguides
Mold modification 2 × 2 optical switch, said waveguide type 2 × 2 optical switch
Chi are arranged in parallel in this order to form the (2k-1) th stage.
The 2M input line optical waveguides and the
2M output lines Optical waveguides 4M optical waveguides are crossed
Waveguide type matrix characterized by being connected without
It is an optical switch.

(4) A waveguide-type matrix optical switch including at least (2M-1) (M is a positive integer of 2 or more) input line optical waveguides and (2M-1) output line optical waveguides. A waveguide type 2 × 2 optical switch and a waveguide type modification 2 × each consisting of an input line optical waveguide and an output line optical waveguide.
It consists of (2M-1) stage switch stage having a second optical switch, the odd-numbered switch stage and the waveguide 2 × 2 optical switches (M-1) pieces of the waveguide-type deformation 2 × 2 Hikarisu <br/> acme switch arranged in parallel in this order, is constructed, the even-numbered switch stage (M-1) pieces of the waveguide shape modification 2 × 2
It is constituted by the waveguide-type 2 × 2 optical switch and optical switch arranged in parallel in this order, wherein between the respective stages (2M-
1) A waveguide type matrix optical switch in which a total of 2 (2M-1) optical waveguides of the input optical waveguides and the (2M-1) output optical waveguides are connected without crossing each other.

(5) A waveguide-type matrix optical switch including at least (2M−1) (M is a positive integer of 2 or more) input line optical waveguides and (2M−1) output line optical waveguides. A waveguide type 2 × 2 optical switch and a waveguide type modification 2 × each consisting of an input line optical waveguide and an output line optical waveguide.
With 2 light switch is composed of a (2M-1) stage switch stage, the odd-numbered switch stage, (M-1) pieces of the waveguide-type deformation the 2 × 2 optical switch and the waveguide 2 X2 optical switches are arranged in parallel in this order, and the even-numbered switch stages are the waveguide type 2x2 optical switch and (M-
1) is constructed by arranging pieces of the waveguide type deformation the 2 × 2 optical switch in parallel in this order, wherein between the respective stages (2M-
1) A waveguide type matrix optical switch in which a total of 2 (2M-1) optical waveguides of the input optical waveguides and the (2M-1) output optical waveguides are connected without crossing each other.

(6) In the waveguide type matrix optical switch according to any one of (2) to (5) , the waveguide type modified 2 × 2 optical switch is the waveguide according to claim 1. It is a modified optical switch.

(7) In the waveguide type matrix optical switch according to any one of (2) to (6) , the waveguide type 2 × 2 optical switch includes one input line optical waveguide and one input line optical waveguide. A 1 × 2 optical switch including an output line optical waveguide and one bypass optical waveguide, the input section being the input line optical waveguide, the output section being the input line optical waveguide and the bypass optical waveguide, and the input section being the output A line optical waveguide, the bypass optical waveguide, and a 2 × 1 optical switch having an output section as the output line optical waveguide, and the 1 × 2 optical switch and the 2 ×
It is a waveguide type 2 × 2 optical switch in which the input line optical waveguide and the output line optical waveguide intersect each other in one optical switch.

(8) In the waveguide type matrix optical switch of the above (7) , in the 1 × 2 optical switch and the 2 × 1 optical switch, two optical waveguides are close to each other at two places and two directionalities are provided. It is a Mach-Zehnder interferometer circuit that constitutes a coupler and has a switch drive terminal.

(9) In the waveguide type matrix optical switch of (7) , the 1 × 2 optical switch and the 2 × 1 optical switch are Y-branch type switches having switch drive terminals.

(10) In the waveguide type matrix optical switch of (7) , the 1 × 2 optical switch and the 2 × 1 optical switch are used.
An optical switch is a directional coupler in which two optical waveguides are close to each other at one place and a switch drive terminal is provided.

Quartz glass or the like, which is widely used at present, is used.
In a glass optical waveguide, a thin film heater is used as a phase shifter.
Using the thermo-optic phase shifter used, at the intersection between the waveguides
The intersection angle is preferably 20 degrees or more.

That is, the present invention is shown in FIGS.
Based on the 2 × 2 optical switch of 1 (d) or FIG. 11 (e)
The intersections are arranged spatially close to each other.
As a result, the crossing portion is, for example, a light switch shown in FIG.
Compared to the one in which two chi are arranged in parallel (Fig. 11 (f))
Can be miniaturized in the w direction.

The waveguide type optical matrix of the present invention has the above-mentioned structure.
Waveguide-type modified 2 × 2 optical switch and FIGS. 11A and 11B
(D) or 2 × 2 optical switch of FIG. 11 (e) has a basic configuration
As the above means (2) to (10)
It is a thing.

In the path-independent configuration, the optical switch elements are arranged such that the input line optical waveguides and the output line optical waveguides are arranged in a positive direction and the optical switch elements are turned upside down and in a downward check pattern. To be done. Therefore, when the double gate type optical switch element is used as the 2 × 2 optical switch element as in the present invention, the cross waveguide of the input line optical waveguide and the output line optical waveguide in the double gate type optical switch element is The optical switch elements configured as a pair as described above are arranged in close proximity.

Therefore, the cross waveguide of the input line optical waveguide generated between the switch stages on the output end side of the switch element and the cross waveguide of the output line optical waveguide generated between the switch stages on the input end side of the switch element are described above. It can be incorporated into an optical switch element configured as a pair. Further, by arranging the cross waveguide generated between these switch stages in the vicinity of the cross waveguide of the input line optical waveguide and the output line optical waveguide in the optical switch element, these four cross waveguides are integrated. It can be configured with one waveguide expanding section.

As described above, the waveguide development portion of the cross waveguides generated between the switch stages which is generated in a path independent type and the waveguide development portion of the cross waveguides in the double gate type optical switch element are collectively described. By laying out in the same waveguide expansion part, it is not necessary to newly provide the waveguide expansion part of the crossed waveguide generated between the switch stages, and the effect of reducing the number of stages by half by adopting the path independent type is sufficient. It is possible to drastically reduce the circuit length (optical path length), and it is possible to reduce the insertion loss while using the double gate type optical switch element that can obtain a high extinction ratio.

[0045]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments (examples) of the present invention will be described below in detail with reference to the drawings.

In all the drawings for explaining the embodiments, those having the same function are designated by the same reference numerals, and the repeated description thereof will be omitted.

In the following embodiments, a silica single mode optical waveguide formed on a silicon substrate is used as an optical waveguide, and a thermo-optical Mach-Zehnder interferometer circuit type 2 × 2 optical switch is used as an optical switch element. The waveguide type matrix optical switch described above will be described. This is because this combination can provide a waveguide-type matrix optical switch having excellent connectivity with a single-mode optical waveguide and having no polarization dependence. However, the present invention is not limited to the above combination.

(Embodiment 1) FIGS. 1 and 4 show an embodiment of an N × N matrix optical switch according to the present invention (particularly N = 2).
4 × 4 of Embodiment 1 as an example of M, M: positive integer)
It is a figure which shows schematic structure of a matrix optical switch.

1 (a), 1 (b) and 1 (c) show the waveguide type deformation 2 × 2 according to the present invention in which two 2 × 2 optical switch elements used in the first embodiment are arranged in pairs. a diagram for Description <br/> bright light switch, FIG. 1 (a) 2 of the present embodiment 1
A plan view in which two × 2 matrix optical switch elements are arranged in pairs, and FIG. 1B is an A-shown in FIG.
A cross-sectional view taken along the line A ', FIG. 1C is FIG.
4 is a cross-sectional view taken along line BB ′ shown in FIG.

In FIG. 1, 1 is a silicon substrate, 2 is a quartz glass clad layer, and 11a-11b and 21a-21b.
Is a silica-based input line waveguide core, 12a-12b, 22a-2
2b is a silica-based output line waveguide core, 13a-13b, 23
a-23b is a silica-based bypass waveguide core, 14a, 14
b, 15a, 15b, 24a, 24b, 25a, 25b
Is a directional coupler.

16a, 16b, 17a, 17b, 26
a, 26b, 27a and 27b are thin film heaters (phase shifters), 18a and 28a are first Mach-Zehnder interferometer circuits, 18b and 28b are second Mach-Zehnder interferometer circuits, and 19 and 29 are double gate type optical switch elements. cross waveguide input line optical waveguide and the output line optical waveguide of the inner, 31a are cross waveguide input line waveguide that occurs between the switch stage of the output end of the switching element, 3 2 b is the input end side of the switch elements Crossing waveguides of output line optical waveguides generated between switch stages ,
Reference numeral 30 is a waveguide development unit.

Waveguide type deformation 2 × 2 used in the first embodiment
A pair of 2 × 2 optical switches in the optical switch consists of two input line optical waveguides and two bypass optical waveguides,
A first 1 × 2 optical switch having an input section as a first input line optical waveguide and an output section as the first input line optical waveguide and a first bypass optical waveguide; and an input section for a second input line optical waveguide. A second 1 × 2 optical switch having a waveguide as an output section and the second input line optical waveguide and a second bypass optical waveguide, and an input section as the first output line optical waveguide and the second bypass optical waveguide. A first waveguide having a waveguide and an output section serving as the first output line optical waveguide
It comprises a x1 optical switch and a second 2x1 optical switch in which the input part is the second output line optical waveguide and the first bypass optical waveguide and the output part is the second output line optical waveguide.

The first input line waveguide is the first input line waveguide.
After constructing a × 2 optical switch, it intersects with the second output line waveguide and the second input line waveguide in this order, and the second input line waveguide is the second 1 × 2 After configuring an optical switch, the optical switch intersects with the first output line waveguide and the first input line waveguide in this order, and the first output line waveguide is the first 2 × 1 optical switch. Before configuring the second output line waveguide and the second input line waveguide in this order, the second output line waveguide includes the second 2 × 1 optical switch. Before the configuration, the first output line waveguide and the first input line waveguide are crossed in this order, and these four crossings in total are the first 1 × 2 optical switch and the second It is located near the center of a region surrounded by the 1 × 2 optical switch, the first 2 × 1 optical switch, and the second 2 × 1 optical switch.

In addition, in the present Embodiment 1, in the above-mentioned 1 × 2 optical switch and 2 × 1 optical switch, two waveguides, which are switch elements that have proven themselves in silica-based glass waveguides, are used.
A Mach-Zehnder interferometer having two directional couplers arranged close to each other and having a switch driving element is used.

[0055] The waveguide type deformation the 2 × 2 optical switch is 1
The basic configuration is a × 2 optical switch and a 2 × 1 optical switch. The 1 × 2 optical switch and the 2 × 1 optical switch have a Mach-Zehnder interferometer type shown in FIG.
It is possible to use the Y-branch optical waveguide type shown in FIG. 3A, the directional coupler type shown in FIG.

[0056] Figure 4 is a region be overall plan layout of the embodiment 1, SLU is the waveguides shape modification 2 × 2 optical switch of FIG. 1 are distribution <br/> location, S23 and S41 is an area that is located in the 2 × 2 optical switch element vertically same directions of a conventional double gate type shown in FIG. 11 (in relative orientation of FIG. 11 (a)), the S32 and S14 11 The conventional double gate type 2 × 2 optical switch element shown in FIG.
A region arranged with 1 (a) with respect to the direction of). 1a-1d, 2a-2d, 3a-3d, 4a-4d are input line optical waveguides, 1c-1b, 2c-2b, 3c-3b, 4
c-4b is an output line optical waveguide, S11, S12, ..., S4
4 2 × 2 optical switch elements, SLU is waveguides shape modification 2 ×
2 optical switch, # 1 to # 4 is an optical switch stage.

In the first embodiment, as shown in FIGS. 1 and 4, the double gate type optical switch element and the path independent structure are combined, and the double gate type optical switch element is arranged in the forward direction. and an optical switch element arranged upside down with the optical switch element which is paired waveguides shape modification 2
× constitute a second optical switch. That, 51 a of the waveguide deployment portion generated between the optical switch stage, 51 b, 51 c of the cross waveguide 31a, a 3 2 b, incorporating the conductor wave path shape modification 2 × 2 optical <br/> switch In addition, it is largely different from the conventional configuration in that it is collectively configured by the same waveguide expansion unit 30 as the waveguide expansion unit for forming the crossed waveguides in each switch element. different.

In the path-independent configuration, in each optical switch element, the optical switch element in which the arrangement of the input line optical waveguides 11a-11b and the output line optical waveguides 12a-12b is positive and the vertically inverted downward optical switch element is arranged. , Arranged in an alternating checkered pattern. Therefore, when the double gate type optical switch element is used as the 2 × 2 optical switch element, the input line optical waveguides 11a-11b, 21 in the double gate type optical switch element are used.
a-21b and output line optical waveguides 12a-12b, 22a-2
2b of the cross waveguides 19 and 29 is disposed at a position Oite close to waveguides shape modification 2 × 2 optical switch configured by a pair as described above. Therefore, the input line optical waveguides 11a-11 generated between the switch stages on the output end side of the switch element
b, 21a-21b, an output line optical waveguide 12 generated between the cross waveguide 31a and the switch stage on the input end side of the switch element.
The cross waveguide 32b of a-12b and 22a-22b is described above.
Of incorporated into waveguides shape modification 2 × 2 optical switch can be constituted, further, the above-mentioned waveguides shape modification 2 × 2 optical Sui <br/> Tsu input line optical waveguides in Ji 11a- 11b, 21a-21b
And the output line optical waveguides 12a-12b, 22a-22b are arranged in the vicinity of the crossed waveguides 19, 29, so that these four crossed waveguides 19, 29, 31a, 32b are collectively expanded into one waveguide. The unit 30 can be used.

As described above, the waveguide expansion portions 51a, 51b, 51 generated between the switch stages that are path-independent.
c the cross waveguide 31a, 3 2 b of, by configuring incorporated in waveguides shape modification 2 × 2 optical switch configured by a pair waveguide deployment of cross waveguide occurring between the switching stage It is no longer necessary to newly provide the parts 51a, 51b, and 51c, and the effect of halving the block due to the introduction of the path-independent type is sufficiently brought out, and the circuit length can be shortened significantly.

Furthermore, the waveguide development portions of the cross waveguides 31a and 32b generated between the switch stages and the waveguide development portions of the cross waveguides 19 and 29 in the double gate type optical switch element are collectively described. By laying out the waveguides in the same waveguide expansion portion 30, the circuit size including the size in the lateral direction perpendicular to the waveguide direction can be reduced.

As shown in FIGS. 1 (b) and 1 (c), the 4 × 4 matrix optical switch of Embodiment 1 has a silica-based waveguide 2 on a silicon substrate 1 having a thickness of 1 mm and a diameter of 6 inches. Was manufactured by a combination of a deposition technique of a silica-based glass film utilizing a hydrolysis reaction of a raw material gas such as SiCl ₄ and GeCl ₄ and a reactive ion etching technique, and a thin film heater was manufactured by a vacuum vapor deposition method and a chemical etching.

Silica-based input line waveguide cores 11a-11b,
21a-21b, silica-based output line waveguide core 12a-12
b, 22a-22b , silica-based bypass waveguide core 13a-
The cross-sectional dimensions of the cores such as 13b and 23a-23b are 6 μm square, and the relative refractive index difference between the core and the clad is 0.75%. The thin film heater has a thickness of 0.1 μm and a width of 4
The length is 0 μm and the length is 3 mm.

The 2 × 2 optical switch element used in the first embodiment is basically composed of a straight waveguide and a curved waveguide having a radius of about 5 mm. Cross waveguide 31a, 3 2 b, 19,
The crossing angles θ and θ ′ of 29 were around 30 degrees. Two directional couplers 1 forming a Mach-Zehnder interferometer circuit
4a, 14b, 15a, 15b, 24a, 24b, 25
The effective optical path length difference between the two waveguides connecting a and 25b was accurately set to 0.775 μm, which is half the signal light wavelength of 1.55 μm. The actual waveguide length difference on the mask pattern was set to 0.775 μm / 1.45 = 0.534 μm in consideration of the refractive index of silica glass being 1.45.

[0064] 2 × 2 optical switch element combining two waveguides shape modification 2 × 2 optical switch size Ji at this time,
W0.9 mm x L16.3 mm, and the size of one 2 x 2 optical switch element is W 0.45 mm x L16.3.
It became mm. When the crossed waveguides between the switch stages are not formed by the same waveguide development part as the crossed waveguides in the switch element, 2 × including the waveguide development part of the crossed waveguides between the switch stages is included. The size of one two-optical switch element was W0.5 mm × L20.1 mm.

Therefore, by adopting the layout structure of the present invention, the circuit length can be shortened by about 20%. The chip size of the entire 4x4 matrix optical switch including the heater driving electrodes is 10x90mm.
Met.

The chip in which this 4 × 4 matrix optical switch is manufactured is cut out by dicing, a heat dissipation plate is provided below the silicon substrate, and a single mode fiber array is connected to the input / output waveguide to be used as a thin film heater. Was connected to the power supply lead, and a 4 × 4 matrix optical switch module was completed.

The 4 × 4 switch operation was confirmed by appropriately selecting the thin film heater to be supplied with power. The power consumption of each thin film heater required for the switch operation was about 0.45 W. Each optical switch element drives two thin film heaters for operation, and the maximum number of optical switch elements operating at the same time is 4 so total power consumption is 0.45W maximum.
It was about × 2 × 4 = 3.6W.

The extinction ratio of the matrix optical switch as a whole is such that the coupling ratio of the directional coupler is 50% ± 1 due to a manufacturing error.
Even with a very large deviation of about 5%, a very excellent value of about 50 dB was obtained. The loss value as a matrix optical switch was 1 to 2 dB including the optical fiber connection loss, and a very low loss value was obtained.

FIG. 5 shows a first embodiment of an N × N matrix optical switch which is the same as the 4 × 4 matrix optical switch and is the object of the present invention (particularly N = 2M, M: a positive integer).
It is a figure which shows schematic structure of the 6x6 matrix optical switch as another Example.

The introduction of the optical waveguide and the manufacturing method of this embodiment are basically the same as those of the above-mentioned 4 × 4 matrix optical switch, except that the scale N of the matrix optical switch is different. FIG at 5, SLU is an area where the waveguide type deformation the 2 × 2 optical switch of FIG. 1 is disposed, S
W1 is a region in which the conventional double-gate type 2 × 2 optical switch elements are arranged in the same vertical direction, and SW2 is a conventional double-gate type 2 × 2 optical switch element is arranged in the opposite vertical direction. It is the area where

Also in this embodiment, the circuit size including the size in the lateral direction perpendicular to the waveguide direction can be reduced as in the case of the 4 × 4 matrix optical switch, and the heater driving electrodes and the like are included. The chip size of the entire 4 × 4 matrix optical switch was 12 mm × 120 mm. As for the device characteristics, the total power consumption was about 5.4 W, the extinction ratio was about 50 dB, and the insertion loss value was about 2 dB including the optical fiber connection loss.

(Embodiment 2) FIG. 6 shows N × N according to the present invention.
Another embodiment of the matrix optical switch (particularly N = 2M-1)
FIG. 6 is a diagram showing a schematic configuration of a 5 × 5 matrix optical switch of Embodiment 2 as an example (M: positive integer).

The outline of the optical waveguide and the manufacturing method of the second embodiment are basically the same as those of the 4 × 4 matrix optical switch of the first embodiment. In the first embodiment, the scale N of the matrix optical switch is an even number, but in the second embodiment
The difference is that the scale N of the matrix optical switch is odd.

[0074] In FIG. 6, SLU is an area where the waveguide type deformation the 2 × 2 optical switch of FIG. 1 is disposed, SW
Reference numeral 1 denotes a region in which the conventional double-gate type 2 × 2 optical switch elements are arranged in the same vertical direction, and SW2 is a conventional double-gate type 2 × 2 optical switch element arranged in the opposite vertical direction. It is the area where

[0075] Thus, with the embodiment 1, a waveguide-type <br/> modification 2 × 2 optical switch switches stage switch I being injured disposed, the waveguide-type deformation the 2 × 2 optical switches and a conventional 2 While the matrix optical switch is composed of two types of switch stages, in which two double-gate type 2 × 2 optical switch elements (forward direction arrangement and reverse direction arrangement) are arranged, the present embodiment 2 is different. in a switch stage waveguide shape modification 2 × 2 2 × 1 or 2 optical switch element of a conventional double gate type optical switch and forward arrangement (forward arrangement) is located, a waveguide-type deformation 2 × 2 2 × 2 optical switch elements one conventional double gate type optical switch and reverse arrangement (reverse arrangement) is configured a matrix optical switch with two stages of switching stages being arranged that there are different from the first embodiment.

Also in the second embodiment, the first embodiment
Similarly, the circuit size can be reduced including the size in the lateral direction perpendicular to the waveguide direction, and the chip size of the entire 5 × 5 matrix optical switch including the heater driving electrodes and the like is 11 mm × 105 mm. Met. The device characteristics are total power consumption of about 4.5 W, extinction ratio of about 50 dB, and insertion loss of 2 dB including optical fiber connection loss.
It was about.

(Embodiment 3) FIG. 7A shows an arrangement of the entire configuration of an 8 × 8 matrix optical switch according to Embodiment 3 of the present invention. In FIG. 7A, 70a to 70e are 1
This is a waveguide bundle consisting of six waveguide bundles 70a to 7
Optical switch stages # 1 to # 8 are arranged at eight positions on the way of 0e. The feature of the 8 × 8 matrix optical switch of the third embodiment shown in FIG. 7A is that the input terminal and the optical switch stage # 1 are
Between optical switch stages # 2 and # 3, between # 4 and # 5,
The points # 6 and # 7, and the optical switch stage # 8 and the output end are connected by waveguide bundles 70b, 70c and 70d each having a bend of 90 to 180 degrees. In other words, the curved waveguide bundles 70b, 70c, 7
0d ( taking into account that the increase in the circuit length due to the curved waveguide bundles 70b, 70c, 70d is also kept in mind ) , eight optical switch stages # 1 to # 8 are arranged on a limited substrate size. It is characterized by doing.

FIGS. 7B and 7C are layout diagrams of the 2 × 2 optical switch elements in each of the optical switch stages # 1 to # 8. In FIG. 7 (b), (c) , SLU is a region where waveguides shape modification 2 × 2 optical switch of FIG. 1 is disposed, SW1 is the 2 × 2 optical switch of a conventional double gate type SW is an area where elements are arranged in the same direction up and down.
Reference numeral 2 is an area in which the conventional double gate type 2 × 2 optical switch elements are arranged upside down. In FIG. 7A, the optical switch stages # 1, # 3, # 5, and # 7 have the same configuration as in FIG.
The optical switch stages having the configuration shown in (b) are arranged, and the optical switch stages # 2, # 4, # 6, and # 8 have the optical switch stages having the configuration shown in FIG. 7C.

In the arrangement in which the input terminal and the output terminal of the waveguide are opposed to each other, the layout of the optical switch stages # 1 to # 8 of the third embodiment has the shortest circuit length (29 cm). By the way, when a normal matrix optical switch by the connection as shown in FIG. 11 of the related art is manufactured on a 4-inch silicon substrate by using the double gate type 2 × 2 optical switch element (the circuit layout is the same as that of the fourth embodiment). The circuit length (optical path length) of the layout similar to (1) was about 60 cm. Therefore, the layout of the third embodiment was able to reduce the circuit length to half or less.

The 8 × 8 matrix optical switch of the third embodiment was manufactured on a silicon substrate having a thickness of 1 mm and a diameter of 4 inches. The chip size was 68 mm × 68 mm. Other circuit concepts and circuit / module manufacturing methods are the same as those in the first embodiment.

8 × 8 switch operation was confirmed by appropriately selecting the thin film heater to be supplied with power. The power consumption of each thin film heater required for the switch operation was about 0.45 W. Each optical switch element drives two thin film heaters for operation, and the maximum number of optical switch elements that operate at the same time (ON) is 8. Therefore, the total power consumption is 0.45W × 2 × 8 maximum. = About 7.2W.

The extinction ratio of the matrix optical switch as a whole was about 50 dB, which was a very excellent value. The loss value of the matrix optical switch as a whole was 4 to 5 dB including the optical fiber connection loss, and a very low loss value was obtained. By the way, in the case of the above-mentioned conventional example, the loss value was 7 to 8 dB including the optical fiber connection loss.
In the circuit of Embodiment 3 , the loss value is reduced by 40% or more.

In the third embodiment, in order to make the input terminal and the output terminal face each other, between the optical switch stage # 1 and the input terminal,
Although a bent waveguide bundle is used between the optical switch stage # 8 and the output terminal, the optical switch is disposed between the optical switch stage # 1 and the input terminal.
It goes without saying that the input end may be provided on the same chip side by using a linear waveguide bundle between the stage # 8 and the output terminal.

(Fourth Embodiment) FIG. 8 shows the overall arrangement of an 8 × 8 matrix optical switch as a fourth embodiment of the matrix optical switch of the present invention. The fourth embodiment is basically the same as the third embodiment except that the overall arrangement of the optical switch stages is different. The fourth embodiment is characterized in that eight optical switch stages are arranged on a limited substrate size, giving the highest priority to minimizing the chip size by appropriately using a bent waveguide bundle. This is different from the third embodiment.

The 8 × 8 matrix optical switch of the fourth embodiment was manufactured on a silicon substrate having a thickness of 1 mm and a diameter of 4 inches. The chip size was 65 × 55 mm.

The 8 × 8 switch operation was confirmed by appropriately selecting the thin film heater to be supplied with power. The power consumption of each thin film heater required for the switch operation was about 0.45 W. Each optical switch element drives two thin film heaters for operation, and the maximum number of optical switch elements that operate at the same time is 8 so total power consumption is 0.45W maximum.
It was about × 2 × 8 = 7.2W.

The extinction ratio of the matrix optical switch as a whole was about 50 dB, which was a very excellent value. The loss value as a matrix optical switch was 5 to 6 dB including the optical fiber connection loss, and a very low loss value was obtained.

In the first to fourth embodiments of the present invention, the crossing angle in the crossing waveguide is set to 30 degrees. Next, the setting of this crossing angle will be considered.

Although it varies depending on the relative refractive index difference of the optical waveguides used and the core size of the waveguides, generally, if the crossing angle is 20 degrees or more, the crosstalk between the two optical waveguides depends on the straightness of light. It can be ignored for practical purposes. In the case of the crossing angle of 30 degrees adopted in the above embodiment, the crosstalk is −60 dB.
The loss in the cross waveguide is 0.1.
It is as low as dB. Generally, the crosstalk and the loss of the crossed waveguides are improved as the crossing angle approaches 90 degrees. However, when the crossing angle is increased, the occupied area of the waveguide expansion portion before and after the crossing waveguides increases and the size of the optical switch element increases. Therefore, it is desirable to make the determination in consideration of the required performance of the matrix optical switch and the allowable bending radius of the optical waveguide.

In the first to fourth embodiments, the case where the signal light wavelength is 1.55 μm is dealt with, but the layout of the present invention can be applied to other wavelengths such as 1.3 μm wavelength.

In the first to fourth embodiments, a matrix optical switch based on silica glass on a silicon substrate has been described. However, other materials such as Mach-Zehnder interferometer circuit type optical switch elements can be used. The present invention can also be applied to polymer optical waveguides, ion diffusion waveguides, and lithium niobate optical waveguides provided with an optical phase shifter using the electro-optic effect.

In particular, the polymer optical waveguide has a thermo-optic effect which is about 10 times as large as that of the silica-based waveguide.
It is possible to easily construct a 1 × 2 optical switch or a 2 × 1 optical switch by the Y branch waveguide as shown in (b), (c), and (d). In this case, waveguides shape modification 2 × in FIG. 1
2 switch can be constituted by the 1 × 2 optical switches and the 2 × 1 optical switch as shown in FIG. 2 (a).

[0093]FIG.(A) is a waveguide including a Y-branch optical waveguide
Mold deformation 2 × 2 light switchChi'sPlan view,FIG.(B) Y branch
An enlarged plan view of the optical waveguide,FIG.(C) isFIG.Shown in (b)
A sectional view taken along the line A-A ',FIG.(D)FIG.
It is sectional drawing cut | disconnected along the B-B 'line shown to (b).
In FIG. 2, 1IsRecon substrate, 45 is polymer
Layer 40, Y-branch optical waveguide, 41, 42, 43
ChildsystemOptical waveguide cores, 44a and 44b are thin film heaters, 30
Is a waveguide development unit.

Further, since the lithium niobate optical waveguide has a large electro-optical effect, the directions shown in FIGS. 3 (b), 3 (c) and 3 (d) are generally known. The 1 × 2 optical switch and the 2 × 1 optical switch can be easily configured by the sex coupler. In this case, the waveguide of FIG.
The road shape modification 2 × 2 switches can be constituted by the 1 × 2 optical switches and the 2 × 1 optical switch as shown in FIG. 3 (a).

[0095] 3 (a) is a plan view of a waveguide-type deformation the 2 × 2 optical switch including a directional coupler, and FIG. 3 (b) is an enlarged plan view of a directional coupler, FIG. 3 (c) A- shown in FIG.
A sectional view taken along the line A ', FIG. 3 (d) is shown in FIG. 3 (b).
4 is a cross-sectional view taken along line BB ′ shown in FIG. 3, 60 is a directional coupler, 61 and 62 lithium niobate-based optical waveguide core, 63a, 63 b are voltage application pressure electrode, 64 denotes an insulating film, 65 is a lithium niobate board, 30
Is a waveguide development unit.

The inventions made by the present inventors are as follows.
Although specifically described based on the embodiment, the present invention
It is needless to say that the present invention is not limited to the above embodiment, and various changes can be made without departing from the scope of the invention.

[0097]

The effects obtained by typical aspects of the invention disclosed in the present application will be briefly described as follows.

(1) The circuit length (optical path length) can be significantly shortened as compared with the matrix switch having the conventional structure, while using the double gate type optical switch element capable of obtaining a high extinction ratio, and Therefore, the insertion loss can be reduced.

(2) The light guide type modified 2 × 2 optical switch of the present invention is not only a basic constituent element of the light guide type matrix optical switch but also used as a double light guide type 2 × 2 optical switch. Also in this case, the size can be made smaller than the conventional parallel arrangement of the light guide type 2 × 2 optical switches.

(3) It is extremely effective in putting a matrix optical switch with a high extinction ratio and insertion loss into practical use.

[Brief description of drawings]

1A and 1B are an enlarged plan layout view and a cross-sectional view when a waveguide type modified 2 × 2 optical switch according to a first embodiment of the present invention is configured by a Mach-Zehnder interferometer.

2A and 2B are an enlarged plan layout view and a cross-sectional view when the waveguide type modified 2 × 2 optical switch of the first embodiment is configured with a Y-branch optical waveguide.

3A and 3B are an enlarged plan view and a cross-sectional view in the case where the waveguide type modified 2 × 2 optical switch of the first embodiment is configured by a directional coupler.

FIG. 4 is an overall plan layout view of the waveguide type 4 × 4 matrix optical switch of the first embodiment.

FIG. 5 is an overall plan layout view of the waveguide type 6 × 6 matrix optical switch of the first embodiment.

FIG. 6 is an overall plan layout view of a waveguide type 5 × 5 matrix optical switch according to a second embodiment of the present invention.

FIG. 7 is an overall plan layout view of a waveguide type 8 × 8 matrix optical switch according to a third embodiment of the present invention.

FIG. 8 is an overall plan layout view of a waveguide type 8 × 8 matrix optical switch according to a fourth embodiment of the present invention.

FIG. 9 is a conceptual diagram showing the configuration of a 4 × 4 matrix optical switch.

FIG. 10 is an overall plan layout view of a conventional thermo-optical 4 × 4 matrix optical switch.

FIG. 11 is an enlarged plan view of a conventional double-gate type 2 × 2 optical switch element, its cross-sectional view, and a plan view in which two of them are arranged in parallel.

FIG. 12 is an overall plan layout view of a conventional 4 × 4 waveguide type matrix optical switch having a path-independent structure.

FIG. 13 is a conceptual diagram for explaining that the target optical switch of the present invention is a switch having a matrix configuration.

FIG. 14 is a diagram showing a configuration example of a conventional 2 × 2 optical switch.

[Explanation of Codes] 1 ... Silicon substrate, 2 ... Quartz glass clad layer, 11
a-11b, 21a-21b ... Silica-based input line waveguide core,
12a-12b, 22a-22b ... Silica-based output line waveguide core, 13a-13b, 23a-23b ... Silica-based bypass waveguide core, 14a, 14b, 15a, 15b, 24a,
24b, 25a, 25b ... Directional coupler, 16a, 16
b, 17a, 17b, 26a, 26b, 27a, 27b
... thin-film heater (phase shifter), 18a, 28a ... first Mach-Zehnder interferometer circuit, 18b, 28b ... second Mach-Zehnder interferometer circuit, 19, 29 ... Input line optical waveguide in double-gate optical switch element Cross waveguide of output line optical waveguide, 31a ... Cross waveguide of input line optical waveguide generated between switch blocks on the output end side of the switch element, 32
b ... Crossed waveguides of output line optical waveguides generated between the switch blocks on the input end side of the switch element, 30 ... Waveguide expanding portion, 40 ... Y branch optical waveguide, 41, 42, 43 ... Polymer optical waveguide core , 44a, 44b ... thin film heater data, 1a-
1d, 2a-2d ~4 a- 4 d ... input line waveguide, 1C -
1b, 2c-2b ~4 c- 4 b ... output line optical waveguide, S11
~ S44 ... 2 × 2 optical switch elements, SLU ... waveguide modification 2 × 2 optical switch, # 1 to # 8 ... optical switch stage, 51
a, 51b, 51c ... Waveguide expanding section for constructing crossed waveguides between switch stages, SW1, SW2 ... Conventional double gate type optical switch element, 60 ... Directional coupler, 61,
62 ... Lithium niobate optical waveguide core, 63a, 63
b ... Voltage applying electrode, 64 ... Insulating film, 65 ... Lithium niobate substrate, 70a-70e, 71a-71j ... Optical waveguide bundle, 70b - 70d, 71b - 71i ... Bending waveguide bundle.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

[Figure 3]

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masayuki Okuno 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (72) Inventor Masahiro Yanagisawa 3-19-3 Nishishinjuku, Shinjuku-ku, Tokyo No. 2 inside Nippon Telegraph and Telephone Corporation (72) Inventor Katsuhide Onose 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation

Claims (9)

[Claims] 1. A waveguide type modified 2 × 2 optical switch pair consisting of two input line optical waveguides, two output line optical waveguides, and two bypass optical waveguides, wherein an input section has a first input. A first 1 × 2 optical switch having a line optical waveguide and an output unit of the first input line optical waveguide and a first bypass optical waveguide, and an input unit of a second input line optical waveguide and an output unit of the first Second input line optical waveguide and a second 1 × 2 optical switch serving as a second bypass optical waveguide; and an input section using the first output line optical waveguide and the second bypass optical waveguide as the output section. A first 2 × 1 optical switch serving as a first output line optical waveguide; an input unit serving as the second output line optical waveguide and the first bypass optical waveguide; and an output unit serving as the second output line optical waveguide. And a second 2 × 1 optical switch, wherein the first input line waveguide is After configuring the 1 × 2 optical switch, the second output line waveguide and the second input line waveguide and intersect in this order, said second input line waveguide,
After configuring the second 1 × 2 optical switch, the first
The output line waveguide and the first input line waveguide in this order, and the first output line waveguide is the first 2 × 1
Before forming the optical switch, the second output line waveguide and the second input line waveguide are crossed in this order, and the second output line waveguide and the second input line waveguide are crossed in this order.
Of the second output line waveguide crosses the first output line waveguide and the first input line waveguide in this order after forming the second 2 × 1 optical switch, and a total of four crossings. Is
The first 1 × 2 optical switch, the second 1 × 2 optical switch, the first 2 × 1 optical switch, and the second 2 × 1
A waveguide-type modified optical 2 × 2 switch, which is located near the center of a region surrounded by optical switches. 2. A waveguide type matrix optical switch including at least 2M (M is a positive integer) input line optical waveguides and 2M output line optical waveguides, one input line optical waveguide and one output line optical waveguide, respectively. A waveguide type 2 × 2 optical switch composed of a line optical waveguide and a waveguide type modified 2 × 2 optical switch are provided, and the M number of the waveguide type modified 2 × 2 optical switches are arranged in parallel (2k− 1) stages (k is an integer of 1 or more and M or less),
The waveguide type 2 × 2 optical switch, (M−1) pieces of the waveguide type modified 2 × 2 optical switch, and the waveguide type 2 × 2 optical switch are arranged in parallel in this order to form a 2k-th stage. And a total of 4M optical waveguides of the 2M input line optical waveguides and the 2M output line optical waveguides are connected between the respective stages without crossing each other, and a waveguide type matrix optical switch. . 3. (2M-1) (M is a positive integer of 2 or more)
A waveguide-type matrix optical switch including at least two input line optical waveguides and (2M-1) output line optical waveguides, wherein the waveguide type 2 includes one input line optical waveguide and one output line optical waveguide. × 2 optical switch and waveguide type modification 2 ×
It is composed of (2M-1) switch stages including two optical switch pairs, and the odd-numbered switch stages are the waveguide type 2 ×.
Two optical switches and (M-1) waveguide type deformation 2 × 2 optical switch pairs are arranged in parallel in this order, and an even-numbered switch stage is (M-1) waveguide type deformations. 2x
Two optical switch pairs and the waveguide type 2 × 2 optical switch are arranged in parallel in this order, and the (2M-1) input line optical waveguides and the (2M-1) are provided between the respective stages. A total of 2 (2M-1) optical waveguides of two output line optical waveguides are connected without crossing each other, and a waveguide type matrix optical switch. 4. (2M-1) (M is a positive integer of 2 or more)
A waveguide-type matrix optical switch including at least two input line optical waveguides and (2M-1) output line optical waveguides, wherein the waveguide type 2 includes one input line optical waveguide and one output line optical waveguide. × 2 optical switch and waveguide type modification 2 ×
It is composed of (2M-1) switch stages including two optical switch pairs, and the odd-numbered switch stages are (M-1) number of the waveguide type modified 2x2 optical switches and the waveguide type 2x. Two
Optical switches are arranged in parallel in this order, and the even-numbered switch stages are the waveguide type 2 × 2 optical switch and (M
-1) The waveguide-type modified 2 × 2 optical switch pairs are arranged in parallel in this order, and the (2M-1) input line optical waveguides and the (2M- 1) A total of 2 (2M-1) optical waveguides of output line optical waveguides are connected without crossing, and a waveguide type matrix optical switch. 5. The waveguide type modified 2 × 2 optical switch comprises:
The waveguide-type modified optical switch according to claim 1, wherein the waveguide-type matrix optical switch according to any one of claims 2 to 4. 6. The waveguide type 2 × 2 optical switch is composed of one input line optical waveguide, one output line optical waveguide and one bypass optical waveguide, and an input portion is the input line optical waveguide.
A 1 × 2 optical switch having an output section as the input line optical waveguide and the bypass optical waveguide, and a 2 × 1 optical switch having an input section as the output line optical waveguide and the bypass optical waveguide and an output section as the output line optical waveguide A waveguide type 2 × 2 optical switch including a switch, wherein the input line optical waveguide and the output line optical waveguide intersect each other between the 1 × 2 optical switch and the 2 × 1 optical switch. The waveguide type matrix optical switch according to any one of claims 2 to 5. 7. The 1 × 2 optical switch and the 2 × 1 optical switch have two optical waveguides that are close to each other at two locations to form two directional couplers and have switch drive terminals. The waveguide type matrix optical switch according to claim 6, which is a Mach-Zehnder interferometer circuit. 8. The waveguide type matrix optical switch according to claim 6, wherein each of the 1 × 2 optical switch and the 2 × 1 optical switch is a Y-branch type switch having a switch driving terminal. 9. The 1 × 2 optical switch and the 2 × 1 optical switch are directional couplers in which two optical waveguides are close to each other at one location and have a switch driving terminal. Item 6. A waveguide type matrix optical switch according to item 6.