JPH0675179A - Matrix optical switch - Google Patents

Abstract

PURPOSE:To reduce light loss at an intersection by providing a switching means on a branch waveguide where P- and Q-axis optical waveguides intersect. CONSTITUTION:This switch is comprised in such a way that plural P-axis optical guides Pi made of a glass material such as quartz, etc., and extending in the direction of P-axis, and plural Q-axis optical waveguides Qj made of the similar material and intersecting with those optical waveguides and extending in the direction of Q-axis are provided, and a branching point Jij is set at a position separated from the intersection Cij of each P-axis optical waveguide and Q-axis optical waveguide, and the branch waveguide Bij made of the similar material as that of the branching point at this point is provided, and furthermore, the switching means 1, 2, are provided at the branch point Jij. Since light can advance the branch waveguide Bij by evading the intersection with high loss, it is possible to obtain a matrix optical switch with remarkably low light loss.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a matrix optical switch (optical path switching device).

[0002]

2. Description of the Related Art Conventionally, a matrix optical switch (optical path switching device) is composed of an optical fiber with an optical connector, and an optical line is switched by replacing the optical connector. The matrix optical switch (optical path switching device) according to this method has a large size and a slow switching speed.
Moreover, there is a drawback that automatic switching becomes complicated, and various matrix optical switches (optical path switching devices) have recently been proposed as means for solving this drawback.

According to the principle of switching, these are roughly divided into (1) semiconductor materials utilizing quantum effects, (2) LiNbO ₃ utilizing nonlinear optical characteristics, etc. (3) polarization characteristics of light There are a glass-based waveguide plus liquid crystal or the like used, and (4) a glass-based waveguide plus matching agent or the like that uses reflection and transmission of light. These methods are described in the order of description (1). The quantum effect is small and the waveguide loss of light in the semiconductor is large,
(2) The ratio of change in optical constant to applied voltage is small and the drift of nonlinear optical characteristics is large, and (3) The scattering of light when light is transmitted through the liquid crystal and the polarization-dependent loss are large. Practical application was extremely difficult.

Under these circumstances, at the present time, a device (4) using a glass-based waveguide plus matching agent or the like, which utilizes reflection and transmission of light, has been developed and proposed. A typical matrix optical switch (optical path switching device) using this method will be described below with reference to FIG. In FIG.
A Y-axis optical waveguide Yj of the same material intersects a plurality of X-axis optical waveguides Xi made of a glass-based material such as quartz at a point P at a non-perpendicular angle 2θ, and this point A is set as a light transmission point. A switching means is provided to switch between the setting of the reflection point and the setting of the reflection point.

This switching means comprises a slit 1 having a width d whose boundary surface with the glass-based material of the optical waveguide is orthogonal to the bisector of the intersection angle 2θ, and the glass which is controlled to enter / exit inside the slit 1. When the slit 1 is filled with the matching agent 2 which is optically matched with the system material, the point A becomes a transmission point as shown in FIG.
If the matching agent 2 is removed from the inside of the slit 1 and the inside of the slit 1 becomes air or a vacuum state, P
Light that has passed through the X-axis optical waveguide Xi as a reflection point is reflected by the Y-axis optical waveguide Yj.

[0006]

However, considering from the viewpoint of the transmission characteristics of light waves, when light travels between two intersecting optical waveguides, the light may pass through or intersect at the intersection. As it travels to another optical waveguide, a small amount of light loss is observed each time it passes through one intersection, and as a result, the total amount of this loss becomes considerably large in a multiplex matrix optical switch. There is inconvenience.

[0007]

The present invention has been made to solve the above-mentioned problems, and means for solving the problems are made of a glass material such as quartz and extend in the P-axis direction. A P-axis optical waveguide and a plurality of Q-axis optical waveguides made of the same material and intersecting with each other and extending in the Q-axis direction, and each P-axis optical waveguide deviates from the intersection with the Q-axis optical waveguide. A branch point is set on the P-axis optical waveguide and Q-axis.
This is a matrix optical switch in which a branching waveguide that intersects the axial optical waveguide is provided, and further switching means is provided at the branching point.

Another means of the present invention is a matrix optical switch according to the above matrix optical switch, characterized in that a low refractive index portion is provided at an incident end portion of the branch waveguide from the P-axis optical waveguide. is there.

Still another means of the present invention is characterized in that, in the above-mentioned matrix optical switch, the branching waveguide is connected to the Q-axis optical waveguide by a curved optical waveguide made of the same material. It is a matrix optical switch.

[0010]

[Function] When the P-axis optical waveguide is moved to the Q-axis optical waveguide, the branch point that is out of the intersection can pass through the branch waveguide, so that the transmission loss can be reduced even a little at each intersection, and in the case of the matrix optical switch as a whole. As a result, a large decrease in light loss can be measured.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First and second embodiments of the present invention will be described with reference to FIG. The difference between the first and second embodiments is the reference numeral 3.
Only the presence or absence of the elements shown in. In the matrix optical switch of the present invention, a plurality of X-axis optical waveguides P1, P
, Pn (hereinafter, these will be represented by Pi as a representative thereof) and a plurality of Q-axis optical waveguides Q1, Q2, ..., Qn (hereinafter represented by Qj) are provided so as to intersect each other at a point Cij. . That is, for example, P-axis optical waveguides P1 and Q
The notation used in this specification is that the intersection of the axial optical waveguide Q2 is represented by C12.

P off one intersection, for example C12
A branch point J12 is set in the axial optical waveguide P1 and switching means 1 and 2 are provided therein. The switching means is composed of the slit 1 having the width d and the matching agent 2 which is controlled in and out of the slit 1 as described in the related art. In FIG. 1, a tank of matching agent 2 is depicted only at intersection C11, but it should be understood that this is installed for slits 1 at all intersections.

A branch waveguide Bij is provided which intersects the P-axis optical waveguide Pi at an intersection Cij at an angle 2θ. The branch waveguide Bij is made of a similar glass-based material such as a P-axis optical waveguide, and obliquely merges with the Q-axis optical waveguide Qj with a small angle α. The straight line bisecting the angle 2θ formed by the P-axis optical waveguide Pi and the branch waveguide Bij into θ is filled with the matching agent 2 in the boundary surface K1 of the slit 1 with the P-axis optical waveguide Pi, that is, in the slit 1. In this case, the angle θ is perpendicular to the reflection surface, and the angle θ is the entrance / reflection angle that satisfies the condition of total reflection.

In the second embodiment of the present invention, the low refractive index portion 3 is provided at the incident end portion of the branch waveguide Bij from the P-axis optical waveguide Pi. When the refractive index of the low refractive index portion 3 is n2, the refractive index of the core portion of the optical waveguide is n1,
The low refractive index portion 3 has a property of satisfying the relationship of n1> n2 ≧ n3, where n3 is the refractive index of the clad portion.
Thus, the optical loss that is reflected and propagated in the branch waveguide Bij is reduced.

FIG. 2 shows a third embodiment of the present invention. In this embodiment, the angle 2θ formed by the P-axis optical waveguide Pi and the branch waveguide Bij in the first embodiment is an obtuse angle larger than 90 degrees, whereas in this embodiment, the angle 2θ is an acute angle smaller than 90 degrees. Is a feature. Of course, there is no change in that the angle θ is an incident / reflection angle that satisfies the total reflection condition. The branch waveguide Bij is a Q-axis optical waveguide Q.
It is connected to j by an optical waveguide 4 made of the same material as those having a curved shape, and it is attempted to reduce the optical loss at this connection portion.

[0016]

According to the present invention, the branch waveguide for connecting the P-axis optical waveguide and the Q-axis optical waveguide is provided,
Since light can travel through this branch waveguide without passing through the intersection of the P-axis optical waveguide and the Q-axis optical waveguide, the transmission loss of light at each intersection is avoided, and the matrix optical switch with extremely small optical loss and There is an advantage that an optical path switching device can be obtained. Further, in the structure in which the low refractive index portion is provided at the end of the branch waveguide, there is an effect that the loss due to reflection can be further reduced.

[Brief description of drawings]

FIG. 1 is a side sectional view showing first and second embodiments of the present invention.

FIG. 2 is a side sectional view showing a third embodiment of the present invention.

FIG. 3 is a side sectional view showing a conventional matrix optical switch.

[Explanation of symbols]

 P, Pi P-axis optical waveguide Q, Qj Q-axis optical waveguide Bij Branch waveguide Cij Intersection point Jij Branch point 1 Slit 2 Matching agent 3 Low refractive index part 4 Curved optical waveguide

Claims (3)

[Claims] 1. A plurality of P-axis optical waveguides (Pi) made of a glass-based material such as quartz and extending in the P-axis direction and a plurality of Q-axis optical waveguides made of the same material and extending in the Q-axis direction intersecting these. (Qj), and a branch point (Jij) is set at a position deviating from the intersection (Cij) of each P-axis optical waveguide with the Q-axis optical waveguide, and at this point, the branch point is made of the same material as the above material, Matrix light obtained by providing a branch waveguide (Bij) intersecting the P-axis optical waveguide (Pi) and the Q-axis optical waveguide (Qj), and further providing switching means (1, 2) at the branch point (Jij). switch. 2. The matrix optical switch according to claim 1, wherein a low refractive index portion (3) is provided at an incident end portion of the branch waveguide (Bij) from the P-axis optical waveguide (Pi). 3. The matrix according to claim 1, wherein the branch waveguide (Bij) is connected to the Q-axis optical waveguide (Qj) by a curved optical waveguide (4) made of the same material. Optical switch.