JP2886479B2 - Filter moving optical switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical switch using an optical filter.

[0002]

2. Description of the Related Art A conventional optical switch using an optical filter is shown in FIGS. In the figure, reference numeral 11 denotes an entrance-side connector, 13 denotes an exit-side connector, 15a denotes a movable-side connector for switching an optical path, 15b denotes a fixed-side connector for switching an optical path, 17
Is an optical filter, 19a and 19b are optical fibers for this optical path, 21
Reference numerals a and 21b denote optical fibers for a bypass optical path, and reference numeral 23 denotes a case.

When the movable connector 15a is at the position shown in FIG. 8, the optical fibers 19a and 19b for the optical path are connected, and an optical signal is transmitted directly from the inlet connector 11 to the outlet connector 13. On the other hand, when the moving side connector 15a is at the position shown in FIG. 9, the main optical path optical fiber 19a and the bypass optical path optical fiber 21a are connected, and the main optical path optical fiber 19b and the bypass optical path optical fiber 21b are connected, respectively. The optical signal input from the inlet connector 11 is transmitted to the outlet connector 13 through the optical filter 17. That is, the optical switch switches between the state shown in FIG. 8 in which the optical signal is transmitted as it is and the state shown in FIG. 9 in which only the optical signal passing through the optical filter 17 is transmitted.

[0004]

The conventional optical switch has the following problems. That is, since the optical path switching connector is used, the optical axis is likely to be displaced in this portion, and it is difficult to repeat the low-loss connection and reproduce the same. In addition, since the bypass optical path is provided separately from the optical path and the optical filter is installed in the bypass optical path, a large component storage space is required, and there is a disadvantage that the optical switch becomes large.

[0005]

SUMMARY OF THE INVENTION The present invention provides a filter-movable optical switch which solves the above-mentioned problems, and has a structure comprising an end face of an optical fiber installed with its optical axis aligned. An optical switch for switching an optical signal by inserting and removing a thin plate-shaped optical filter between the movable member and a movable member made of a magnetic material that supports the optical filter, and a guide that guides the movable member in a moving direction of the optical filter. And a stopper made of a magnetic material installed at both ends of the guide, a permanent magnet that magnetizes the movable body so that both ends have the same polarity, and a coil that generates a magnetic field in the moving direction of the movable body.
(Claim 1).

Another configuration of the present invention is an optical switch for switching an optical signal by inserting and removing a thin plate-shaped optical filter between the end faces of optical fibers installed with their optical axes aligned. A permanent magnet that is magnetized in the moving direction of the optical filter, a guide that guides the permanent magnet in the moving direction of the optical filter, a stopper made of a magnetic material installed at both ends of the guide, and a stopper at both ends. A coil magnetized so that the inside has the same polarity is provided (claim 2).

[0007]

The optical switch of the first aspect operates as follows.
For convenience of explanation, the stopper at one end of the movable body is referred to as a first stopper, and the stopper at the other end is referred to as a second stopper. When the optical filter is out of the space between the end faces of the optical fiber, one end of the movable body magnetized by the permanent magnet is attracted to the first stopper. This state is maintained even when no current is flowing through the coil. In this state, a current is applied to the coil to generate a magnetic field in the coil that weakens the magnetic force at one end of the movable body and increases the magnetic force at the other end. Then, the movable body moves to the other end side and sticks to the second stopper. Thus, the optical filter is in a state of being inserted between the end faces of the optical fiber. This state is maintained even when the coil current is cut off, since the movable body is magnetized by the permanent magnet. Next, a current is applied to the coil in the opposite direction to generate a magnetic field in the coil that increases the magnetic force at one end of the movable body and weakens the magnetic force at the other end. Then, the movable body moves to one end side and sucks on the first stopper. As a result, the optical filter is brought into (a state) protruding from between the end faces of the optical fiber. This state is maintained even when the coil current is turned off.

This optical switch switches an optical signal by inserting and removing an optical filter between the end faces of an optical fiber as described above. The state in which the optical filter protrudes from between the end faces of the optical fiber and the state in which the optical filter enters between the end faces of the optical fiber are caused by the movable body magnetized by the permanent magnet being attracted to one of the stoppers.
Self-held.

The optical switch according to the second aspect operates as follows. For convenience of explanation, the stopper at one end of the permanent magnet is referred to as a first stopper, and the stopper at the other end is referred to as a second stopper. With the optical filter protruding outside between the end faces of the optical fiber, one end of the permanent magnet is attracted to the first stopper. This state is maintained even when no current is flowing through the coil. In this state, a current is applied to the coil to magnetize the first stopper so as to repel the permanent magnet and the second stopper to attract the permanent magnet. Then, the permanent magnet moves to the other end side and sticks to the second stopper. Thus, the optical filter is in a state of being inserted between the end faces of the optical fiber. This state is maintained even when the current of the coil is turned off, since the permanent magnet is attracted to the second stopper. Next, a current in the opposite direction to that described above is applied to the coil so that the first
The second stopper is magnetized so as to attract the permanent magnet and repel the second stopper. Then, the permanent magnet moves to one end side and sticks to the first stopper. As a result, the optical filter is brought into (a state) protruding from between the end faces of the optical fiber. This state is maintained even when the coil current is turned off.

In this optical switch, the optical filter is put in and out between the end faces of the optical fiber as described above to switch the optical signal. The state in which the optical filter protrudes from between the end faces of the optical fiber and the state in which the optical filter enters between the end faces of the optical fiber are self-held by the permanent magnet being attracted to one of the stoppers.

[0011]

【Example】

[Embodiment 1] FIGS. 1 to 3 show an embodiment of the first aspect of the present invention. In the drawing, reference numerals 25a and 25b denote an optical fiber provided with a gap between the end faces and aligned with the optical axis, and reference numeral 27 denotes a thin plate-shaped optical filter which is put in and taken out between the end faces of the optical fibers 25a and 25b.

The optical filter 27 is supported by a movable body 29 made of a magnetic material (iron bar or the like). The movable body 29 is housed in a cylindrical guide 31 made of a non-magnetic material (such as aluminum).
The optical filter 27 is movable in a direction to enter and exit between the end faces of the optical fibers 25a and 25b. An intermediate portion of the guide 31 is cut out so as not to hinder the movement of the optical filter 27 (see FIG. 1). Stoppers 33a and 33b made of a magnetic material (such as an iron plate) are fixed to both ends of the guide 31.

A permanent magnet is provided outside the intermediate portion of the guide 31.
35 are installed. The permanent magnet 35 is installed with one magnetic pole (N pole in the illustrated example) facing the guide 31. The movable body 29 is magnetized by the permanent magnet 35 so that both ends have the same polarity. In the illustrated example, both ends of the movable body 29 are N poles. A coil 37 for generating a magnetic field in the moving direction of the movable body 29 is wound around the outer periphery of the guide 31.

In the state shown in FIG. 2, the movable body 29 sticks to the first stopper 33a, and the optical filter 27 is attached to the optical fiber 25a.
25b shows a state in which it is out of between the end faces. In this state, an optical signal is directly transmitted from the optical fibers 25a to 25b. In this state, even if no current is flowing through the coil 37, the permanent magnet
Since the movable body 29 magnetized by 35 is attracted to the first stopper 33a, it is held by itself.

Next, in the state shown in FIG. 2, when a current is applied to the coil 37 in the direction of the arrow, a magnetic field is generated in the coil 37, and an S pole appears on the left end of the coil shaft and an N pole appears on the right end. As a result, on the left end side, since the magnetic field of the movable body 29 is the N pole and the magnetic field of the coil 37 is the S pole, they cancel each other out and the magnetic force is weakened. Therefore, the force with which the movable body 29 sticks to the first stopper 33a is reduced. On the other hand, on the right end side, the magnetic field of the movable body 29 is N-pole,
Since the magnetic field of the coil 37 is also N-pole, the magnetic force is strengthened by each other, and the force attracting to the second stopper 33b is increased. The moment the left and right gravitational forces reverse, the movable body 29
Moves rightward, and becomes the state of FIG.

In the state shown in FIG. 3, the movable body 29 sticks to the second stopper 33b, and the optical filter 27 is attached to the optical fiber 25a.
It is in the state between the end faces of 25b. In this state, an optical signal is transmitted from the optical fibers 25a to 25b via the optical filter 27. Optical signals that do not pass through the optical filter 27 are cut here. In this state, even if the current flowing through the coil 37 is stopped, the movable body 29 magnetized by the permanent magnet 35 is attracted to the second stopper 33b, so that the state is maintained.

Next, when a current is applied to the coil 37 in the direction of the arrow (in the direction opposite to that of FIG. 2) in the state shown in FIG. S pole appears. As a result, on the right end side, the magnetic field of the movable body 29 is N-pole,
Since the magnetic field of the coil 37 is the south pole, they cancel each other out and the magnetic force is weakened. Therefore, the force with which the movable body 29 sticks to the second stopper 33b is reduced. On the other hand, on the left end side, the magnetic field of the movable body 29 is the N pole, and the magnetic field of the coil 37 is also the N pole. Therefore, the magnetic forces are strengthened with each other, and the force attracted to the first stopper 33a is increased. At the moment when the left and right attractive forces are reversed, the movable body 29 moves to the left and enters the state of FIG. This state is maintained even when the current flowing through the coil 37 is stopped.

This optical switch switches the optical signal by putting the optical filter 27 in and out between the end faces of the optical fibers 25a and 25b as described above. Switching can be performed by simply passing a current through the coil 31 for a short time.

In this embodiment, the permanent magnet 35 is installed with the north pole facing the guide 31. However, the permanent magnet 35 may be installed with the south pole facing the guide 31. In that case, the operation of the optical switch is reversed. Further, when a plurality of permanent magnets are attached around the guide with the same pole facing the guide, the self-holding force can be further increased.

In order to prevent reflection at the end face of the optical fiber, a refractive index matching agent such as silicone oil may be inserted between the end faces of the optical fiber. If the area where the optical filter moves, as well as the end face of the optical fiber, is immersed in the refractive index matching agent, the optical filter can be protected from the shock generated when the optical filter moves. In order to prevent reflection at the end face of the optical fiber, one method is to incline the end face of the optical fiber.

[Embodiment 2] FIGS. 4 and 5 show another embodiment of the present invention. This embodiment differs from the first embodiment in that the optical fibers 25a and 25b, the optical filter 27 and the permanent magnet 35 are moved to one end of the guide 31. Other configurations and operations are the same as those of the first embodiment, and thus the same portions are denoted by the same reference numerals and detailed description thereof will be omitted.

[Embodiment 3] FIGS. 6 and 7 show an embodiment of the second aspect of the present invention. In the drawing, reference numerals 25a and 25b denote an optical fiber provided with a gap between the end faces and aligned with the optical axis, and reference numeral 27 denotes a thin plate-shaped optical filter which is put in and taken out between the end faces of the optical fibers 25a and 25b.

The optical filter 27 includes a permanent magnet 39 serving as a movable body.
It is supported by. The permanent magnet 39 is housed in a cylindrical guide 31 made of a non-magnetic material (such as aluminum), and is movable in a direction in which the optical filter 27 enters and exits between the end faces of the optical fibers 25a and 25b. An intermediate portion of the guide 31 is cut out so as not to hinder the movement of the optical filter 27 (see FIG. 1). Magnetic material (iron plate etc.) at both ends of guide 31
The stoppers 33a and 33b are fixed.

The permanent magnet 39 is magnetized so that one end in the moving direction is an N pole and the other end is an S pole. In the illustrated example, the first stopper 33a side is the N pole, and the second stopper 33b
The side is an S pole (the opposite is also possible). A first coil 41 for magnetizing the first stopper 33a is provided on the outer periphery of the first stopper 33a.
a is wound, and a second coil 41b is magnetized around the outer periphery of the first stopper 33b. The first coil 41a and the second coil 41b are formed of one conductor, but have opposite winding directions. Even by applying a current from either for the first stopper 33a and second stopper 33b is inside the same polarity (the outside becomes the polarity of the opposite) are magnetized so.

In the state shown in FIG. 6, the permanent magnet 39 sticks to the first stopper 33a, and the optical filter 27
a, 25b are out of the space between the end faces. In this state, an optical signal is directly transmitted from the optical fibers 25a to 25b. This state is obtained by applying a current in the direction of the arrow to the coils 41a and 41b. That is, when a current in the direction of the arrow is supplied to the coils 41a and 41b, the first stopper 33a and the second stopper
The stopper 33b is magnetized to the S pole on the inside and the N pole on the outside, so that the permanent magnet 39 is attracted to the first stopper 33a. This state is maintained by the magnetic force of the permanent magnet 39 even when the current flowing through the coils 41a and 41b is stopped.

Next, in the state shown in FIG. 6, when a current is applied to the coils 41a and 41b in the direction opposite to the arrow, the first stopper 33a
7, the permanent magnet 39 is attracted to the second stopper 39b, and the state shown in FIG. 7 is obtained.

In the state shown in FIG. 7, the permanent magnet 39 sticks to the second stopper 33b, and the optical filter 27
a and 25b are in the state between the end faces. In this state, an optical signal is transmitted from the optical fibers 25a to 25b via the optical filter 27. Optical signals that do not pass through the optical filter 27 are cut here. This state is maintained by the magnetic force of the permanent magnet 39 even when the current flowing through the coils 41a and 41b is stopped.

Next, in the state shown in FIG. 7, when a current is applied to the coils 41a and 41b in the direction opposite to the arrow, the first stopper 33a
As shown in FIG. 6, the permanent magnet 39 is attracted to the first stopper 39a because the inside is magnetized to the S pole and the outside is magnetized to the N pole. This returns to the state of FIG. 6, and this state is maintained even when the current flowing through the coils 41a and 41b is stopped.

This optical switch switches the optical signal by inserting and removing the optical filter 27 between the end faces of the optical fibers 25a and 25b as described above. Switching can be performed by simply passing a current through the coil 31 for a short time. The means for preventing reflection at the end face of the optical fiber is the same as in the first embodiment.

[0030]

The optical switch of the present invention employs a system in which an optical filter is put in and taken out between the end faces of optical fibers installed with their optical axes aligned, so that a conventional optical path switching connector is not required. There is no deviation of the optical axis.
In addition, since there is no need to provide a bypass optical path and the optical filter is moved by a permanent magnet and a coil, the overall size can be reduced. Furthermore, the state in which the optical filter is out between the end faces of the optical fiber and the state in which it is between the end faces are self-held by the magnetic force of the permanent magnet, so that the operation does not become unstable even during a power failure.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an optical switch according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the optical switch of FIG. 1, showing a state in which an optical filter protrudes between end faces of an optical fiber.

FIG. 3 is a cross-sectional view of the optical switch of FIG. 1, showing a state in which an optical filter is between end faces of an optical fiber.

FIG. 4 is a cross-sectional view of an optical switch according to another embodiment of the present invention, showing a state in which an optical filter protrudes from between end faces of an optical fiber.

5 is a cross-sectional view of the optical switch of FIG. 4, showing a state where an optical filter is between end faces of an optical fiber.

FIG. 6 is a cross-sectional view of the optical switch according to one embodiment of the present invention, showing a state in which the optical filter protrudes from between the end faces of the optical fiber.

7 is a cross-sectional view of the optical switch of FIG. 6, showing a state in which an optical filter is between end faces of an optical fiber.

FIG. 8 is a plan view showing a state in which an optical filter of a conventional optical switch does not enter an optical path.

9 is a plan view showing the optical switch of FIG. 9 in a state where an optical filter is in an optical path.

[Explanation of symbols]

 25a, 25b: optical fiber 27: optical filter 29: movable body 31: guide 33a: first stopper 33b: second stopper 35: permanent magnet 37: coil 39: permanent magnet 41a, 41b: coil

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Nobuo Tomita 1-6-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (58) Fields investigated (Int. Cl. ⁶ , DB name) G02B 26 / 00-26/08

Claims (2)

(57) [Claims] 1. An optical switch for switching an optical signal by inserting and removing a thin plate-shaped optical filter between end faces of optical fibers installed with their optical axes aligned, the optical switch comprising a magnetic material supporting the optical filter. A movable body, a guide for guiding the movable body in the moving direction of the optical filter, a stopper made of a magnetic material installed at both ends of the guide, and a permanent magnet for magnetizing the movable body so that both ends have the same polarity. And a coil for generating a magnetic field in the moving direction of the movable body. 2. An optical switch for switching an optical signal by inserting and removing a thin plate-shaped optical filter between end faces of optical fibers installed with optical axes aligned, said optical filter supporting said optical filter. A permanent magnet magnetized in the moving direction of the optical filter, a guide for guiding the permanent magnet in the moving direction of the optical filter, a stopper made of a magnetic material installed at both ends of the guide, and a stopper at both ends having the same polarity on the inside. 1. A filter-movable optical switch, comprising: a coil that magnetizes the filter.