JPS59192231A - Optical switch - Google Patents

Abstract

PURPOSE:To simplify the constitution of an optical switch and to switch the optical path nonmechanically by forming an electrode near the center of the side face of a rod-shaped lens along the optical axis of the lens. CONSTITUTION:The optical switch consists of an input-side optical fiber 1, output-side optical fibers 2 and 3, and a rod-shaped lens 4 which connects input and output optical fibers and has an electrode 5 on the side face. The electrode 5 is formed near the center of the side face of the rod-shaped lens along the optical axis of the lens. In a state (a) where power is not supplied to the electrode 5, the light from the fiber 1 is made incident to the fiber 3, and fibers 1 and 3 are in the connection state. When power is supplied to the electrode 5, the temperature near the electrode rises, and therefore, the refractive index is changed by this heating, and the light from the fiber 1 is deflected and is made incident to the fiber 2, and fibers 1 and 2 are in the connection state. Thus, the constitution of the optical switch is simplified, and the optical path is switched nonmechanically.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-mechanical optical switch inserted into an optical fiber line to switch an optical transmission line.

Generally, an optical switch consists of a mechanical type switch that switches the optical path by moving an optical element of an appropriate shape such as an optical fiber, prism, or mirror, and a movable part that switches the optical path using electro-optic effect or magneto-optic effect. It can be broadly classified into non-mechanical type switches that do not have

The former type of optical switch has a switching speed of several milliseconds.
Although it is not as fast as e c, it has low insertion loss and low crosstalk, and has been put to practical use in optical fiber data links, TV image monitoring systems, etc. However, since this type of optical switch has a movable part, there are concerns about long-term switching reliability and strong vibrations, shocks, etc.

On the other hand, since the latter type of switch has no moving parts, it does not have the above concerns, but at present it has large insertion loss and crosstalk, and does not have practical performance.

In addition, in principle, polarization plane circuits, phase interference, coupling between waveguides, etc. are used, so the applicable optical fiber is limited to single mode fibers. The combination of polarizing elements complicates the optical system.

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly reliable optical switch with low insertion loss and a simple optical configuration using a non-mechanical switching type, which can be applied to both single mode fibers and multimode fibers.

To explain the configuration of the present invention, the present invention provides an optical switch inserted into an optical fiber line, which includes an input side (or output side) optical fiber, a plurality of output side (or input side) optical fibers, A rod-shaped lens is inserted between the input-side optical fiber and the output-side optical fiber to couple the two, and an electrode is formed near the center of the side surface of the rod-shaped lens along the optical axis of the lens, This is an optical switch that switches the optical path by energizing this electrode.

The basic structure and embodiments of the present invention will be described below with reference to the drawings.

The basic configuration of the optical switch of the present invention is shown in FIG.

In the figure, the optical switch of the present invention has an input side (or output side) optical fiber 1, output side (or input side) optical fibers 2 and 3, and an electrode 5 on the side surface that connects the input and output optical fibers. It is composed of a rod-shaped lens 4. The electrode 5 is formed near the center of the side surface of the rod-shaped lens along the optical axis of the lens.

The operation of the optical switch of the present invention will be explained with reference to FIG. In FIG. 2, a graded inch lens whose refractive index has an approximately square distribution is used as an example of a rod-shaped lens. First, in a state (a) in which the electrode 5 is not energized, light from the fiber 1 enters the fiber 3, and the fibers 1-3 are in a connected state. Next, as shown in state (b), when the electrode 5 is energized, the temperature rises in the vicinity of the electrode, and due to the heat generation, the refractive index changes to d n / in the depth direction, as shown in FIG. Materials with positive d 'I' (where n is the refractive index and T is the temperature) are shown as solid lines, and d
Since the substance with negative n/dT changes as shown by the broken line, the light from the fiber 1 is deflected and enters the fiber 2, and the fibers 1 and 2 are connected. In Figure 2, dn/dT
The case where is positive is shown.

FIG. 4 shows a case where a biconvex lens is used as the rod-shaped lens. Fibers 1-3 are connected when no current is applied, and fibers 1-2 are connected when energized. In the case of the above-mentioned graded intex lens, a 5EL FOC lens whose material is a glass medium, such as thallium glass ion-exchanged with potassium or sodium, is used, but when using the biconvex lens shown in Fig. 4, any dielectric material is used. Since it can be applied to body materials, if a substance with a large dn/d'L'', such as PLZT%L i N b O3, is used,
Can be driven with low power.

FIG. 5 shows an example of application of the present invention.

This is achieved by forming electrodes 5 and 7 on both sides of the lens 4.
Electrode 5 is energized when connecting fibers 1-2, and electrode 7 is energized when connecting fibers 1-3. If electrodes are formed on both sides of the lens as shown in FIG. 5, the deflection angle required for switching can be halved compared to the configurations shown in FIGS. 1 and 4, and low power driving is possible.

In the embodiment of the present invention, the same configuration as in FIG. 1 is used, a single mode fiber with a core diameter of 10 μm is used as the optical fiber, the output fibers 2 and 3 are separated by 30 μm, and the lens is a selfoc lens (diameter 2 bolts, length g10.5mm
) was used. After optically polishing both sides of the lens with 0.7 scratches to a thickness of 0.6 mvt, electrodes (Ni-C
r material) was formed. When DC60V was applied to this electrode, the light beam was deflected by 0.65° and the output fiber could be switched. Insertion loss is less than 2dB, crosstalk is -40
It was less than dB.

As described above, according to the present invention, electrodes are formed on the rod-shaped lens that connects optical fibers, and the lens itself has a deflecting action, so the structure of the optical switch is simple and non-conventional. It is possible to mechanically switch the optical path, has a bulk type configuration, and can be applied to both single mode and multimode fibers.If a material whose refractive index does not depend on polarization is used as a lens medium, polarization dependence can be avoided. A neutral light switch is obtained. Furthermore, the optical switch of the present invention has low insertion loss and has no moving parts, allowing highly reliable switching.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the basic configuration of the optical switch of the present invention;
Figure 2 shows the operating principle of the optical switch of the present invention.
(a) is a diagram showing the state before energizing the electrode, (b) is a diagram showing the state after energizing, Figure 3 is a diagram showing the change in refractive index in the depth direction due to electrode energization, and Figure 4 is a biconvex lens as a rod-shaped lens. FIG. 5 is a diagram showing an example of application of the present invention. 1.2.3... Optical fiber, 4... Rod-shaped wire/zu, 5, 7... Electrode, 6...
・Biconvex rod-shaped lens. -==--E 0"A""'"8"6 艷 弗 1 figure strong 2 figures bend J loaf rate change figure 4

Claims (4)

[Claims] (1) In an optical switch inserted into an optical fiber line, an input side (or output side) optical fiber, a plurality of output side (or input side) optical fibers, and the input side optical fiber and the output side optical fiber are connected to each other. It consists of a rod-shaped lens that is inserted between the fibers and connects them. An electrode is formed near the center of the side surface of the rod-shaped lens along the optical axis of the lens, and by energizing this electrode, the optical path is changed. A light switch characterized by switching. (2) Claim 1 characterized in that both the input side surface and the output side surface of the rod-shaped lens are flat, and the electrode is arranged only on one side surface of the rod-shaped lens.
Light switch as described in section. (3) The light according to claim 1, wherein both the input side surface and the output side surface of the rod-shaped lens are flat, and electrodes are arranged on both side surfaces of the rod-shaped lens. switch. (4) The optical switch according to claim 1, wherein both the input side surface and the output side surface of the rod-shaped lens form a convex lens.