JPH0555045B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical switch for switching optical coupling between optical fibers.

(Prior art) Conventionally, optical switches include, for example,
As shown in No. 107201, a right angle prism is provided to face the input/output terminals of these lights for three optical fibers arranged in parallel in the same plane, and this right angle prism is connected to the three optical fibers. It is known that the optical coupling between the optical fibers is switched by moving the optical fibers in a direction orthogonal to the fibers within the same plane.

Alternatively, as shown in FIG. 11, a right angle prism 104 having a rotating shaft 110 coaxially with the central optical fiber 101 among the optical fibers 101, 102, 103 is provided, and this right angle prism 1
The optical coupling between the optical fibers 101 and 102 or 101 and 103 is switched by rotating the optical fiber 04 by 180 degrees in a plane perpendicular to the plane on which the optical fibers 101 to 103 are provided. Are known.

(Problem to be Solved by the Invention) However, in the former case, the right angle prism is linearly reciprocated to perform switching in such a conventional optical switch. The direction of the rectangular prism coincides with the adjustment direction of the right angle prism with respect to the optical axis, so there is a drawback that distortion tends to occur in this adjustment position with use, and it is also susceptible to the influence of gravity due to its mounting orientation. There is a drawback that a difference tends to occur in the switching time between the two.

On the other hand, in the latter case, since the prism is rotated 180 degrees, it takes time to switch, and the switching speed of the switch becomes slow.

A common drawback of both is that since the input/output terminal surface of the optical fiber and the input/output surface of the prism are installed parallel to each other, they are susceptible to the influence of reflected light from both entrance surfaces.

(Means for Solving the Problem) In order to solve the problem, the present invention arranges second and third optical fibers in parallel on the same side in the same plane on both sides of the central first optical fiber, In the optical switch, the coupling of light is switched between the first optical fiber and the second optical fiber or the third optical fiber via a movable reflector, wherein the movable reflectors are arranged orthogonally to each other. It is composed of a first reflector and a second reflector that have a relationship with each other, and the vertical bisector passing through the vertex of this movable reflector is the radius of the arc, and the movable reflector is oscillated in both left and right directions around the center point of the arc. The optical fiber is supported so as to be movable and rotatable, and light is coupled between the first optical fiber and the second optical fiber or the third optical fiber when the swinging is stopped.

(Function) According to this configuration, the switch can be changed by swinging and rotating at a predetermined angle without moving the prism linearly, and the posture can be adjusted by balancing the weight of the movable reflector. Optical coupling is achieved without being influenced by errors, and in a state where the entrance/exit surface of the prism and the entrance/exit surface of the optical fiber are not parallel.

(Example) Examples of the present invention will be described below based on the accompanying drawings.

FIGS. 1 to 3 are diagrams showing the optical switch according to the present invention, FIGS. 4 to 6 are diagrams showing the principle, and FIG.
Figures 1 through 10 are diagrams showing setting conditions.

First, the principle of the optical switch according to this embodiment will be briefly explained based on FIGS. 4 to 6. In FIG. 4, reference numerals 1 to 3 indicate optical fibers arranged in parallel on the same side in the same plane, and fiber collimators 1a to 3a are provided at the input/output terminal portions of the optical fibers. Reference numeral 4 designates a right angle prism which is a movable reflector of the present invention and is provided to face the fiber collimators 1a to 3a. This right angle prism 4 includes an entrance/exit surface 4a, a first reflector 4b, a second reflector 4c,
A perpendicular bisector of the entrance/exit surface 4a passing through the vertex of the rectangular prism 4 constitutes a radius r of a circular arc, and the optical fibers 1 to 3 are arranged side by side on the same plane with a swing rotation radius equal to the radius r. It is provided so that it can swing in both left and right directions around the center point of the circular arc. This swinging rotation angle is approximately α on both the left and right sides of the input/output optical axis A of the central optical fiber 1.
The optical fiber 1 and the second optical fiber 2 are optically coupled, and the first optical fiber 1 and the third optical fiber 3 are connected to each other in a state in which the optical fiber 1 and the second optical fiber 2 are stopped swinging as shown by the broken line. Optically coupled.

The driving torque for swinging and rotating the right angle prism 4 is obtained by magnetic force using a permanent magnet and an electromagnet. FIGS. 5 and 6 are diagrams illustrating this principle.

In the figure, 5 is a rotating magnet made of a permanent magnet that rotates the right angle prism 4, while 6 and 7 are stators provided to face this rotating magnet 5, and are magnetized as necessary by a magnetomotive coil to be described later. . The gap between the rotating magnet 5 and the stators 6, 7 is relatively narrow in the stator parts 6a, 7a.
The stator portions 6b and 7b are relatively wide, and therefore the magnetic field between the rotating magnet 5 and the stators 6 and 7 is strongest near the stator portions 6a and 7a. Therefore, when the stators 6 and 7 are not magnetized by the magnetomotive coil, the rotating magnet 5
The N pole 5a and the S pole 5b are the stator parts 6a and 7.
Therefore, when the north pole and the south pole are aligned on the line X'-X' in FIG. 5, the torque of the rotor becomes zero.

The dotted line in FIG. 6 indicates the rotation angle θ of the rotating magnet 5.
This diagram shows the detent torque T that acts on the rotating magnet at this time, and the angle θ when the N and S poles of the rotating magnet 5 coincide on the X'-X' line shown in FIG. 5 is 0.
It is shown as On the other hand, the solid line in FIG. 6 shows the relationship between the driving torque T acting on the rotating magnet 5 and its rotation angle when the stators 6 and 7 are magnetized.
In the range 0° < θ < 90°, the direction of torque is opposite when the stators 6 and 7 are magnetized, and when the stators 6 and 7 are not magnetized, the direction of the torque is counterclockwise; , 7, a clockwise torque is generated on the rotating magnet 5.

In this embodiment, in this embodiment, a first stopper 8 is provided to prevent the rotation angle of the rotating magnet 5 from satisfying θ≦ _θ1 between 0°<θ<90°, as shown by the imaginary line in FIG. Then, a second stopper 9 is provided to prevent the rotation angle from θ≧θ ₂ , and when the stators 6 and 7 are not magnetized, the rotor part 17b has a slight rotational force and moves to the first stopper 8.
On the other hand, when the stator is magnetized, the part 17c of the rotor comes into contact with the second stopper 9 with a slight rotational force and becomes stopped, and the stop position is changed. It is stable.

In this embodiment, the value of θ ₂ −θ ₁ is 20°.

And these optical fiber collimators 1a, 2
The setting conditions of a, 3a, the right angle prism 4, its swing rotation radius r, etc. are such that they satisfy the following equation using the parameters shown in FIG.

l=2・r・sinα−√2・a・tanβ・cosα (1) l=D>0 (2) √2・a・cosα・(1−tanβ)>D+l (3) n・sin(π/ 4-β)>1 (4) Here, α is the rotation angle of the right-angle prism with respect to the optical axis A, the incident angle of light, a is the length of the two sides of the right-angle prism that sandwich the right angle, and l is the adjacent ray. β is the refraction angle of the incident light, n is the refractive index of the prism, and D is the width of the light ray.

Note that equation (4) is an equation that indicates the total internal reflection condition within the prism, and is therefore an unnecessary condition when the present optical switch is configured with a mirror or the like instead of the prism.

Figures 8 to 10 illustrate the relationship between each parameter that satisfies conditional expression (1), and Figure 8 shows the relationship between the swing rotation radius r and the rotation angle α for two types of parameter (a = 10 mm, a = 3 mm), Figure 9 shows the distance l between the optical axes and the rotation angle α
Figure 10 shows the relationship between the optical axis distance l and the rotation radius r using a specific rotation angle r and the prism side length a.
and the length a of the side of the prism, and for reference, a suitable example is illustrated by dotted lines.

Based on the above explanation, the structure of the optical switch based on FIGS. 1 to 3 will be explained. In the figure, 10 is a rotating shaft, and this rotating shaft 10 has bearings 11 at its upper and lower ends.
12 to the upper plate 13 and lower plate 14, respectively, and the contact surface 10a between the upper bearing 11 and the rotating shaft.
A slight gap S is provided between the two. This rotating shaft 10 has spring plates 15 and 1 near the top and bottom, respectively.
6, and a stable operating state is maintained.

A support base 17 for mounting the right angle prism 4 is fixed to the rotating shaft 10, and a rotating magnet 5 is fixed to the lower surface of the support base 17. This support stand 17 is made of an aluminum plate, and has a support part 17a on the front part on which the right-angled prism 4 is placed, and contact parts 1 on both sides thereof which come into contact with the first and second stoppers 8 and 9.
7b and 17c are further formed with a protruding portion 17d at the rear thereof for maintaining balance. Therefore, the rotating magnet 5 is assembled with the lower surface of the support base 17 as a reference, and its attachment can be easily and accurately performed. Furthermore, since the center of gravity of the entire rotating body can be set approximately on the rotation axis, the magnitude of the inertial force acting at the stop position is constant, and positional errors are minimized.

The stators 6 and 7 arranged so as to face the rotating magnet 5 have a step slightly lower than the rotating magnet 5, and constantly urge the rotating shaft 10 downward to stabilize its rotational operation. . These stators 6 and 7 are magnetized by passing a current through a coil 18, and together with a yoke 19 inserted through this coil, form a magnetic loop.

The stoppers 8 and 9 are comprised of screws that pass through a portion of the upper plate 13, and the restricting position of the support base 17 can be easily adjusted by adjusting the screws.

(Effects of the Invention) As is clear from the above explanation, according to the present invention, the optical coupling between each optical fiber is switched by swinging and rotating the movable reflector, so that the movement of the movable reflector is It is possible to make the adjustment direction different from the adjustment direction with respect to the optical axis, and therefore, it is possible to eliminate the conventional drawback that the adjustment position tends to be twisted due to the influence of inertia caused by the movement of the reflector. Therefore, together with the small rotation angle, the parallelism of the optical axis is easily maintained during operation, making it less susceptible to unstable factors such as thermal expansion and deformation of the parts used, and even heat cycles etc. It can demonstrate stable reliability under various loads.

Furthermore, the swinging and rotational motion of the movable reflector is not affected by gravity depending on its mounting orientation, and there is little difference in switching time between the two. Furthermore, since the movable reflector is oscillated and rotated on an arc to switch the optical path,
The rotation angle can be made small and the response of optical path switching is good.
The switching time can also be shortened. It is also less susceptible to the effects of reflected light. Moreover, the optical axis can be easily adjusted.

In addition, since the optical fibers are installed parallel to each other on the same side, not only can the optical switch itself be made smaller, but it is also easier to process, requires less space for routing the optical fibers, and reduces the overall size of the optical switch. Space saving can be achieved.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an optical switch according to the present invention, FIG. 2 is a front sectional view, and FIG. 3 is a back sectional view.
Fig. 4 is a diagram showing the principle of the present invention, Figs. 5 and 6 are diagrams showing the rotation principle, Figs. 7 to 10 are diagrams showing setting conditions, and Fig. 11 is a diagram showing the prior art. be. In the drawings, 1 is a first optical fiber, 2 is a second optical fiber, 3 is a third optical fiber, 4 is a right angle prism, 5 is a rotating magnet, 6 and 7 are stators,
10 is a rotation axis.

Claims (1)

[Scope of Claims] 1. Second and third optical fibers are arranged in parallel on the same side in the same plane at both ends of the central first optical fiber, and the first optical fiber and the second optical fiber are arranged in parallel on the same side in the same plane. In an optical switch that switches the coupling of light between a fiber or a third optical fiber via a movable reflector, the movable reflector is connected to a first optical fiber having a mutually orthogonal relationship.
It is composed of a reflector and a second reflector, and swings in both left and right directions around the center point of the arc, with the perpendicular bisector of the entrance and exit plane passing through the apex of this movable reflector as the radius of the arc. An optical fiber that is rotatably supported, and that light is coupled between the first optical fiber and the second optical fiber or the third optical fiber when the optical fiber is in a non-swinging state. Switch.