JP2003149566A - Optical switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical switch which can be made small-sized and inexpensive by decreasing the number of movable optical switch elements. SOLUTION: Four input optical fibers IN-1,..., IN-4, and output optical fibers OUT-1,..., OUT-4, are arranged on two mutually orthogonal sides on the top surface of a triangular silicon substrate 11 respectively, fixed optical switch elements 2 are arranged at four lattice points along a 45 deg. oblique side, and movable optical switch elements 3 each having mirror surfaces 3a and 3b as both of its surfaces are arranged at N(N-1)/2 lattice points, wherein N is 4, thereby composing the optical switch 1 of the small number of movable optical switch elements 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical switch for switching input light used in an optical communication system or the like and outputting it.

[0002]

2. Description of the Related Art In an optical communication system or the like, it is necessary to switch the light transmitted by an optical fiber,
An optical switch is used as this switching device. Figure 6
4 schematically shows a 4 × 4 matrix optical switch 50 as an example of a conventional matrix optical switch disclosed in Japanese Patent Laid-Open No. 2000-258705. In the optical switch 50 having the configuration as shown in FIG. 6, 4 × 4
A movable mirror 51 is arranged at each lattice point of the matrix. By moving the movable mirror 51 mechanically, for example, it is possible to switch the optical paths in two directions orthogonal to each other, that is, the row direction and the column direction of the matrix. ing.

In addition, on the extension of each row of the matrix, an input optical fiber column 52 (input optical fiber of each row is IN-1,
, ..., IN-4) are arranged, while the output optical fiber row 53 (the output optical fibers of each row are indicated by OUT-1, ..., OUT-4) is provided on the extension of each row. ) Has been placed.

The fibers forming the input optical fiber row 52 and the output optical fiber row 53 are, for example, spherical fibers and are positioned and fixed in the V grooves 55 provided on the substrate 54 shown in FIG. With such a configuration, the lights respectively emitted from the input optical fiber trains 52 can be made incident on any of the output optical fiber trains 53. Therefore, by switching the movable mirror 51,
A desired optical path can be constructed.

Further, the input optical fiber array 52 is composed of 4
The input optical fibers of the book are sequentially moved away from the positions of IN-1, ..., IN-4, for example, from the position of the first row of the matrix (in Fig. 6, distances Ca, P2, P2, and P2 are increased).
Further, the tips of the four output optical fibers OUT-1, ..., OUT-4 forming the output optical fiber column 53 are sequentially brought closer to, for example, the position side of the fourth row of the matrix (intervals P1, P1 in FIG. 6). , P1 and Cb approach each other),
The optical path lengths of all the optical paths are made equal to each other so that a difference in coupling efficiency due to a difference in optical path length does not occur.

[0006]

However, in the conventional N × N matrix optical switch as shown in FIG. 6, N × N movable mirrors (movable optical switch elements) 51 for switching the optical path are required. There are drawbacks that the number of parts increases, the size also increases, and the manufacturing cost also increases.

(Object of the Invention) The present invention has been made in view of the above points, and is a movable mirror (movable optical switch element).
It is an object of the present invention to provide an optical switch that can be reduced in size and cost by reducing the number of components.

[0008]

The invention of claim 1 is N ×
In an N-matrix optical switch, a movable optical switch element capable of simultaneously switching light beam paths in two directions orthogonal to an n-row m-column lattice point satisfying n> m is arranged, and an n-row m-column lattice satisfying n = m. The optical switch is characterized in that a fixed optical switch element is arranged at each point. By making it possible to simultaneously switch the light beam paths in two directions orthogonal to the movable optical switch element, the light emitted from the input optical fibers located in each row of the matrix can be made incident on any of the output optical fibers. By switching the movable optical switch element, it is possible to realize optical paths of any combination of the input optical fiber and the output optical fiber.

Therefore, according to the present invention, only N (N-1) / 2 movable optical switching elements and fixed optical switching elements are used.
Conventional N × N which requires × N movable optical switch elements
An optical path switching function similar to that of a matrix optical switch can be realized.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 relate to one embodiment of the present invention, FIG. 1 schematically shows the configuration of a 4 × 4 matrix optical switch according to one embodiment of the present invention, and FIG.
4 matrix optical switch and its components are shown more specifically, FIG. 3 shows a modified 4 × 4 matrix optical switch, FIG. 4 shows an N × N matrix optical switch, and FIG. A specific configuration of an N × N matrix optical switch is shown.

An optical switch 1 according to an embodiment of the present invention shown in FIG. 1 is a schematic example of a 4 × 4 matrix optical switch as a simple concrete example of an N × N matrix optical switch. is there. As shown in FIG. 1, in the optical switch 1 of the present embodiment, the optical switch elements that reflect light are not arranged at all the lattice points of the 4 × 4 matrix, that is, the lattice points along the diagonal of the 4 × 4 matrix, that is, 1 row 1 column,
Fixed fixed optical switching elements 2 are arranged at lattice points of 2 rows, 2 columns, 3 rows, 3 columns, and 4 rows, 4 columns.

Further, the diagonal line of this 4 × 4 matrix is 2
One of the divided grid points, that is, the second row to the fourth row in the first column
Movable movable optical switch elements 3 are respectively arranged at 9 lattice points of the row portion, the third to fourth row portions of the second column, and the fourth row portion of the third column. In FIG. 1, the fixed optical switch element 2 is shown in black so that it can be easily distinguished from the movable optical switch element 3 which is movable.

In addition, on the extension of each row of the 4 × 4 matrix, an input optical fiber column 4 (input optical fiber of each row is IN-
1, ..., IN-4) are arranged, while the output optical fiber row 5 (the output optical fibers of each row are denoted by OUT-1, ..., OUT-4) is provided on the extension of each row. ing)
Are arranged.

Then, the light emitted from the input optical fibers IN-1, ..., IN-4 constituting the input optical fiber array 4 is moved by a fixed optical switch element 2 arranged along a diagonal line by a drive signal. An output optical fiber OUT that forms an output optical fiber row 5 by adjusting the optical path by the movable optical switch element 3 set to the reflection state and the passing state (non-reflection state).
-1, ..., OUT-4 can be selectively made incident. That is, the input optical fiber IN-J (J
= 1, ..., 4), the light emitted from the output optical fiber OUT-K
(K = 1, ..., 4) can be made incident.

A more specific configuration of FIG. 1 is shown in FIG. FIG. 2A shows the optical switch 1 of FIG. 1 more specifically, FIGS. 2B and 2C show the configuration of the movable optical switch 3, and FIG. 2B does not apply a voltage. 2 is a plan view showing the movable optical switch 3 which is set in a reflective state.
(C) shows the movable optical switch 3 which is set to a state where it is not reflected by applying a voltage, as seen from the output optical fiber array 5 side.

As shown in FIG. 2A, two orthogonal sides of the upper surface of a conductive semiconductor silicon substrate 11 in the form of a trapezoid or a triangle (for example, an isosceles triangle) having a hypotenuse of 45 degrees. Each part has a predetermined pitch, for example pitch P
, IN-4 forming the input optical fiber row 4 in the groove formed by the rear end (emission end) of the input optical fiber and the output light forming the output optical fiber row 5 The ends (incident end) of the fibers OUT-1, ..., OUT-4 are positioned and fixed, respectively.

That is, four input optical fibers IN-1,
, IN-4 are positioned and arranged along the direction of the first row, ..., The fourth row, and four output optical fibers OUT-1,
, OUT-4 are positioned and arranged along the direction of the first row, ..., The fourth row.

Further, along the 45-degree oblique side on the upper surface of the semiconductor silicon substrate 11, four lattice points facing each other in the row direction and the column direction are formed by subjecting one surface of the plate-shaped member to aluminum vapor deposition or the like. The fixed optical switch elements 2 each having a mirror surface 2a are positioned and fixed. In addition,
The mirror surface 2a is set at an angle of 45 degrees with respect to the incident light (and 45 degrees with respect to the emitted light), and reflects the incident light in a direction orthogonal to each other.

Also, on the upper surface of the semiconductor silicon substrate 11, lattice points facing the output optical fiber OUT-1 and facing the input optical fibers IN-2, IN-3, IN-4, respectively, the output optical fiber OUT-. 2 of the grid points facing the input optical fibers IN-3 and IN-4, and 6 of the grid points facing the output optical fiber OUT-3 and facing the input optical fiber IN-4.
The movable optical switch elements 3 are respectively drivable at locations (N (N−1) / 2 locations where N is 4).

The lattice points on the upper surface of the semiconductor silicon substrate 11 where the movable optical switch elements 3 are arranged are shown in FIG.
As shown in FIGS. 2B and 2C, a recess 13 having, for example, a rectangular shape is formed.

A disk-shaped movable electrode 15 is supported in the recess 13 so as to be vertically movable via an elastic supporting member 14 such as a spring as shown in FIG. 2B.
A double-sided mirror 16 having mirror surfaces 3a and 3b reflecting on both sides is erected and mounted on the above to form the movable optical switch element 3. The mirror surfaces 3a and 3b of the movable optical switch element 3 are set at an angle of 45 degrees with respect to the incident light (and 45 degrees with respect to the emitted light), and in the reflecting state, the incident light is orthogonal to each other. Reflect in the direction.

The movable electrode 15 has a conductive electrode film formed on its upper surface (or lower surface coated with insulation) and the like, and the double-sided mirror 16 is not reflected between the electrode film and the semiconductor silicon substrate 11. A signal line (not shown) for applying a drive signal for setting the reflective state is connected. And
In the state in which the drive signal (specifically, the voltage signal) is not applied, as shown by the chain double-dashed line in FIG.
It is located at a position projecting upward from the concave portion 13 (by the urging force of 4), and in this state, incident light is reflected by the mirror surfaces 3a and 3b on both sides thereof as shown in FIG. 2B.

On the other hand, when a voltage is applied, as shown by the solid line in FIG. 2C, it is attracted by electrostatic force and moves to the bottom surface side of the recess 13 (against the biasing force of the elastic supporting member 14). However, in this state, the incident light passes above it. As described above, in the present embodiment, the double-sided mirror 16 constituting the movable optical switch element 3 is a binary signal by no voltage application / application, and is projected / depressed in the direction perpendicular to the 4 × 4 matrix surface to be on / on the optical path. It can be set to the position retracted from.

In FIG. 1 or FIG. 2A, for example, light emitted from the input optical fibers IN-1, IN-2, IN-3, IN-4 is output optical fibers OUT-3, OUT-4, OU.
It is shown in the case of controlling to switch to T-1 and OUT-2.

For this reason, for example, the two movable optical switch elements 3 in the third row and the first column and the fourth row and the second column are set to the reflective state without applying a voltage, and the remaining four movable optical switch elements 3 are set. An example in which a voltage is applied to the element 3 to set it in a non-reflection state is shown. In FIG. 1, the movable optical switch element 3 in the reflective state is shown by a solid line, and the movable optical switch element 3 in the non-reflective state is shown by a dotted line.

In this case, the light emitted from the input optical fiber IN-4 is in the movable state of the movable optical switch element 3 which is in the reflection state (referred to as the ON state for simplification) at the lattice point in the fourth row and the second column.
And is incident on the output optical fiber OUT-2.
Further, the light emitted from the input optical fiber IN-3 is reflected by the movable optical switch element 3 in the third row and the first column, and enters the output optical fiber OUT-1.

The light emitted from the input optical fiber IN-2 is reflected by the fixed optical switching element 2 in the second row and the second column and after being reflected by the movable optical switching element 3 in the fourth row and the second column, It is reflected by the fixed optical switch element 2 of 4 rows and 4 columns, and enters the output optical fiber OUT-4.

The light emitted from the input optical fiber IN-1 is reflected by the fixed optical switch element 2 in the first row and the first column,
After being reflected by the movable optical switch element 3 in the third row and the first column,
It is reflected by the fixed optical switch element 2 in the third row and third column, and is incident on the output optical fiber OUT-3. In the example above, N
In the × N matrix optical switch 1, N = 4, but N may be any integer (natural number) as long as it is 2 or more.

FIG. 3 shows a modified optical switch 1B. This optical switch 1B has a configuration in which four fixed optical switch elements 2 are replaced with one fixed optical switch element 12 in FIG. 2 (A). This fixed optical switch element 12
Has an elongated mirror surface 12a so as to cover four grid points along the diagonal line from the 1st row and 1st column to the 4th row and 4th column. Others are the same as those of the optical switch 1 of FIG.

According to FIG. 3, the fixed fixed mirror is 1
Even in this case, an optical path switching function equivalent to that in the case of FIG. 2A can be realized. Although a movable double-sided mirror is used as the movable optical switch element 3 in FIGS. 2 and 3, the same function can be realized by using a bubble type optical switch element.

FIG. 4 shows the configuration of the N × N matrix optical switch 21 of the present invention as a general example. In this N × N matrix optical switch 21, without arranging optical switch elements that reflect at all the lattice points of the N × N matrix, lattice points along the diagonal of the N × N matrix, that is, 1 row, 1 column, 2 rows. Fixed optical switching elements 2 are arranged at lattice points of 2 columns, 3 rows and 3 columns, ..., N rows and N columns.

The diagonal line of this N × N matrix is 2
N (N-1) movable optical switch elements 3 are arranged on the side of one of the divided grid points, that is, the second row to N-th row portion of the first column,
The movable optical switch element 3 is arranged at each lattice point of the third row to the N-th row portion of the second column, ..., And the N-th row portion of the (N−1) th column.

Further, on the extension of each row of the N × N matrix, the input optical fiber column 4 (the input optical fiber of each row is IN-
1, IN-2 ..., IN-N) are arranged, while the output optical fiber row 5 (the output optical fibers of each row are OUT-1, OUT-2, … OU
(Denoted by TN) are arranged.

The input optical fibers IN-1, ..., IN
-The light emitted from -N is fixed optical switch element 2 arranged along a diagonal line, and movable optical switch element 3 is moved by a drive signal to be set to a reflection state and a passing state (non-reflection state).
Is used to adjust the optical path so that the light can be selectively incident on the output optical fibers OUT-1, ..., OUT-N forming the output optical fiber array 5. That is, the light emitted from the input optical fiber IN-J (J = 1, ..., N) can be made incident on the output optical fiber OUT-K (K = 1, ..., N).

In this case, in order to form a desired optical path, the switching state of the movable optical switch element 3 located in each row is determined in the order of the Nth row, the (N-1) th row, ..., The first row. I will do it. The light emitted from the input optical fiber IN-m in the m-th row (m = 1, 2, ..., N) is transmitted to the n-th (n = 1, 2, ...
, N) The method of determining the switching state of the movable optical switch element 3 located in the m-th row so as to be incident on the output optical fiber OUT-n of the column is shown below.

(I) In the case of m> n, the movable optical switch element 3 located at the lattice point of the m-th row and the n-th column is turned on (reflection state). (Ii) When m = n All the movable optical switch elements 3 located in the m-th column are turned off (non-reflection state).

(Iii) When m <n When the mirror in the ON state of the movable optical switch elements 3 located in the n-th row is located in the l-th column, the input of the m-th row is performed. The light emitted from the optical fiber IN-m is
The switching state of the movable optical switch element 3 located in the m-th row may be determined so that the light is incident on the mirror surface 3b of the movable optical switch element 3 located at the lattice point in the n-th row and the l-th column.

For example, when m> l, the movable optical switch element 3 located at the lattice point of the m-th row and the l-th column is turned on. When m = 1, all the movable optical switch elements 3 located in the m-th column are turned off. When m <l, of the movable optical switch elements 3 positioned in the l-th row, the mirror surface 3 of the movable optical switch element 3 that is in the ON state.
The switching state of the movable optical switch element 3 located in the m-th row is determined so that the light emitted from the input optical fiber IN-m in the m-th row is incident on b.

According to the above method, only N (N-1) / 2 movable optical switch elements 3 and the fixed mirror 2 are used, and the conventional N
It can be seen that the same optical path switching as the × N matrix optical switch can be performed.

FIG. 5 shows a specific example of the N × N matrix optical switch 21. When the array pitch of the movable optical switch elements 3 in the row direction and the column direction is P, the input optical fibers IN-1, IN-2, ..., IN-N of the N input optical fiber rows 4 are arranged.
The rear end (outgoing end) is arranged so as to be distant from the first column of the matrix by a distance of the pitch P, and N
Output optical fibers OUT-1 of the book output optical fiber array 5;
The tip (incident end) of OUT-N is the Nth matrix of the matrix.
The rows are arranged so that the distances P are sequentially approached.

The distance between the rear end of the input optical fiber IN-1 in the first row and the movable optical switch element 3 in the first column is C1, and the distance is Nth.
When the distance between the output optical fiber OUT-N of the column and the movable optical switch element 3 of the Nth column is C2, each input optical fiber IN
Optical path length LN from -J to each output optical fiber OUT-K
Are all represented by LN = 2 (N-1) P + C1 + C2.

That is, all the optical path lengths from the respective input fibers IN-J to the respective output optical fibers OUT-K are the same. Therefore, the input optical fiber IN-J
Also, even if a front spherical fiber is used as the output optical fiber OUT-K, a difference in coupling efficiency due to a difference in optical path length does not occur, so that it is possible to realize good connection performance with little variation in light amount.

Therefore, the present embodiment has the following effects. According to the N × N matrix optical switch of the present embodiment, compared with the conventional optical switch, the number of movable optical switch elements can be reduced and the same optical path switching can be performed. Therefore, it is possible to provide a small and inexpensive N × N matrix optical switch with a small number of movable optical switch elements. Further, by arranging the movable double-sided mirror so that the incident angle of the incident light beam is 45 °, the function of the movable optical switch can be realized.

[Additional Notes] 1. The fixed optical switch element according to claim 1, wherein the fixed optical switch element is one fixed mirror having a mirror surface on one surface arranged so as to cover lattice points of n rows and m columns satisfying the condition of n = m. 2. In claim 1, the N input optical fibers and the N output optical fibers are arranged such that the optical path lengths from the arbitrary input optical fibers to the arbitrary output optical fibers become equal.

[0045]

As described above, according to the present invention, N
N input optical fibers located on the extension of each row of the N matrix, N output optical fibers located on the extension of each column of the matrix, and arranged at each lattice point of the matrix. In an optical switch equipped with an optical switch element for switching optical paths in two directions orthogonal to each other, a movable optical switch element capable of simultaneously switching optical paths in two directions orthogonal to lattice points of n rows and m columns satisfying n> m is arranged. , N =
Since fixed optical switch elements are arranged at lattice points of n rows and m columns that satisfy m, the number of movable optical switch elements can be significantly reduced, and a compact and low-cost optical switch can be provided. .

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a 4 × 4 matrix optical switch according to an embodiment of the present invention.

FIG. 2 is a diagram more specifically showing a 4 × 4 matrix optical switch and its constituent elements.

FIG. 3 is a diagram showing a configuration of a 4 × 4 matrix optical switch of a modified example.

FIG. 4 is a diagram showing a configuration of an N × N matrix optical switch.

FIG. 5 is a diagram showing a more specific configuration of an N × N matrix optical switch.

FIG. 6 is a diagram showing a configuration of a 4 × 4 matrix optical switch in a conventional example.

[Explanation of symbols]

1 ... Optical switch 2 ... Fixed optical switch element 2a ... Mirror surface 3 ... Movable optical switch element 3a, 3b ... Mirror surface 4 ... Input optical fiber array 5 Output optical fiber array 11 ... Silicon substrate 12 ... 13 ... Recess 14 ... Elastic support member 15 ... Movable electrode 16 ... Double-sided mirror IN-1 to IN-4 ... Input optical fiber OUT-1 to OUT-4 ... Output optical fiber

Claims (3)

[Claims] 1. N input optical fibers located on an extension of each row of an N × N matrix, N output optical fibers located on an extension of each column of the matrix, and each of the matrices. In an optical switch equipped with an optical switch element arranged at a lattice point to switch optical paths in two directions orthogonal to each other, a movable light path in two directions orthogonal to a lattice point of n rows and m columns satisfying n> m can be simultaneously switched. An optical switch characterized in that an optical switch element is arranged, and a fixed optical switch element is arranged at a lattice point of n rows and m columns satisfying n = m. 2. A fixed mirror constituting a fixed optical switch element linearly arranged on one side of a polygonal substrate and a movable double-sided mirror constituting the movable optical switch element arranged in a matrix on the polygonal substrate, The optical switch according to claim 1, wherein the optical switch is arranged so that an incident angle of an incident light beam from the input optical fiber is 45 °. 3. The movable optical switch element is applied with a voltage /
2. The optical switch according to claim 1, wherein the optical switch is projected and retracted in a direction perpendicular to the plane of the N.times.N matrix by no application.