JPS6039630A - High-speed optical switch - Google Patents

Abstract

PURPOSE:To perform high-speed optical switching with small insertion loss and a low driving voltage by reducing the interval between then electrodes provided to a PLZT. CONSTITUTION:Incident light from a lens 4 to a polarization separator 5 is separated into an S and a P wave, which enter PLZTs 6 and 7. While a voltage is applied to neither PLZT6 nor 7, they enter a photodetector 15 through a lens 9, connector 11, and optical fiber 13. When the voltage is applied, electrooptic effect converts the P wave into an S wave and the S wave into a P wave by rotating their planes of polarization by 90 deg.. Consequently, the S wave light passed through PLZT6 and P wave light passed through PLZT7 are both outputted to a polarization multiplexer 8, lens 10, connector 12, and optical fiber 14 and sent to a detector 16. Thus, the light is switched to the detectors 15 and 16 according to whether the voltage signal is applied to thin electrodes to PLZTs 6 and 7. Then, the intervals of the thin electrodes 61 and 62, and 71 and 72 are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a high-speed optical switch using PLZT. More specifically, the present invention uses a groove-shaped electrode as the electrode structure of PLZT, and also uses polarized light as an optical system.
This paper is about nine high-speed optical switches using separation and synthesis.

<Description of Prior Art> As a conventional optical switch, a mechanical type that switches an optical path by mechanically moving an optical system such as an optical fiber or a prism has been put into practical use. This type of mechanical light switch is
Although it is easy to reduce the crosstalk to -50 dB or less, it has the disadvantage that it takes a long time to switch FCl2 and is susceptible to vibration and shock.

Furthermore, when configuring a system using these optical switches, it is desirable that the system not include any moving parts, as this improves reliability. For this reason, various non-mechanical optical switches have also been proposed. Examples of non-mechanical optical switches include those using the magneto-optic effect (e.g. "Optical communication switch using magneto-optic effect" Asama, Shirasaki 1 Japan Society of Applied Magnetics Vol. 16°N□, 5 (1982) PP265~
269), those using liquid crystals (for example, bar Elec
strictly controlled optic
al 5w1tch format fi
ber applications J R, B, W
Agner, and J-Cheng, Appl.
0ptics, Vol i9. No. 17 (19
80) PP2921-2925), those using LiNbO3 optical waveguides (“Integrated 0pt
ical 5w1tch Matrix for Si
ngle-ModeFiber Networks J
M, Kondo etal, IEEE, J.
Qvan.

Else, Vol, QB-18 (1982) PP
1759-1765) etc.

However, those using the magneto-optical effect and those using liquid crystal both have very small insertion losses of 1.4 to 0.40, but have the disadvantage of slow switching speed. Furthermore, although the switch speed using the LiNbO3 optical waveguide is extremely fast, the insertion loss is as large as 6 dB, and the fabrication is difficult and expensive.

<Objective of the Present Invention> The present invention has been made in view of these drawbacks in the prior art, and aims to realize an optical switch with high switching speed and low insertion loss.

<Summary of the present invention> The device according to the present invention inputs input light into a polarization separator composed of a beam splitter and a total reflection prism, and uses a PLZT
Light switching is performed by a voltage signal applied to a groove-shaped electrode provided in the wafer.

<Explanation of Examples> FIG. 1 is a configuration diagram showing an example of an apparatus according to the present invention.

In the figure, 1 is a light source such as a Fi laser or LED, 2 is a light source that guides the light from the light source 1, 7 is an optical fiber, and 3 is an optical fiber 2.
A fiber optic connector that connects to The part SW surrounded by a solid line is an optical switch part, and the inside thereof is, for example, 40
The temperature is maintained at ~50°C. In the optical switch section SW, 4 is a lens that condenses the input light passing through the optical fiber connector 5, 5 is a polarization separator configured by combining a beam splitter 51 and a total reflection prism 52, and ζ. Input light enters through the lens 4. 6 and 7 are PLZTs installed so as to be irradiated with the 8 waves and the P waves output from the polarization separator 5, respectively, and these K are provided with groove-shaped electrodes 61.62 and 71.72. 65 and 75 are round drive terminals that provide switching signals to each groove electrode.

Reference numeral 8 denotes a polarization combiner constructed by combining a beam splitter 81 and a total reflection prism 82, through which each O output light is guided to the optical fiber 13, 14 and ψ1.

15.16 is the output controlled by the switch section SW! the light,
It is a photodetector that receives light through optical fibers 13 and 14.

is used, and the surface has a depth of 3001m @70
Groove-shaped electrodes 61 and 62 are provided to form grooves 63 with a diameter of approximately pm, and to face each other at and ζ. The length of these groove-shaped electrodes 61 and 62 is 200 to 300 yen,
The distance between the electrodes 61 and 62 is also about 200 to 300 V, which is designed to reduce the capacitance between the electrodes, increase the switching speed, and control the control voltage to about 80 to 100 V. The optical system is adjusted so that the beam waist of the S wave (or P wave) from the polarization separator 8 irradiated here passes near the middle between the electrodes 61 and 62 (hatched area). Note that each electrode 61
On the PLZT surface between
6 K and S waves enter PLZT 7, respectively.

, 9 and PLZT6 (7) are groove-shaped electrodes 61.62
Between! No electro-optic effect occurs unless pressure is applied. Therefore, in this state, both the P wave that has passed through the PLZT 6 and the S wave that has passed through the PLZT 7 pass through the lens 9 and the optical fiber connector 11, are output to the optical fiber 13@, and are sent to the photodetector 15. It will be done. PLZT6 (7
) When a voltage is applied between the groove-shaped electrodes 61 and 62, an electro-optic effect occurs, and the plane of polarization of the P wave passing through it turns into an S wave, and the S wave turns into a P wave, respectively, by 90 degrees. As a result,
The light that passes through the PLZT 6 and becomes an S wave, and the light that passes through the PLZT 7 and becomes a P wave, both enter the polarization combiner 8, pass through the lens 10 and the optical fiber connector 12, and are output to the optical fiber 14 side. and sent to the photodetector 16.

According to the device configured in this way, each PLZT 61
By applying or not applying a voltage signal to the groove-shaped electrode 7, input light can be switched to the photodetectors 15 and 16 at high speed.

The nine beams guided by the plurality of optical fibers 21, 22...2n are turned into parallel beams by the SELFOC lens 40, and after passing through the polarization separator 5, are transmitted between the corresponding electrodes of the PLZT 6. pass. As shown in the plan view of FIG. 4, this -PLZT 6 has a plurality of grooves 63 arranged at a predetermined pitch, and groove-shaped electrodes 61 are provided in these grooves 63. A voltage can be selectively applied between each groove-shaped electrode via a lead wire (not shown).

The light exiting the PLZT 6 passes through a polarization combiner 8 and is connected to optical fibers 141, 142...14 corresponding to the selected portion.
guided by n.

<Effects of the present invention> As explained above, according to the apparatus according to the present invention, the PL
By reducing the spacing between the groove-shaped electrodes provided on the ZT, light can be switched at high speed with low insertion loss and low drive voltage. Incidentally, according to an optical switch using PLZT having the dimensions shown in FIG. 2, the driving voltage is 80~
At 100 V, switch speed 115 (IMHz
), a configuration explanatory diagram showing an actual optical switch with an insertion loss of 14 dB, a configuration cross-sectional diagram showing another example of the device of the present invention as the third cause,
FIG. 4 is a plan view of PLZT used in the device shown in FIG. 5.

5...Polarization separator, 6,7...P zone T% 41.62°
“1 groove electrode, 8...polarized light synthesizer.

Claims (1)

[Claims] (1) A polarization separator consisting of a beam in which the input light is incident, a total reflection prism, and groove-shaped electrodes arranged opposite to each other, and the polarization separator separates the input light between the two groove-shaped electrodes. PLZT is irradiated with P waves and S waves respectively.
, is composed of a beam splitter and a total reflection prism, and the P
1. A high-speed optical switch comprising a polarization combiner into which light that has passed through an LZT is incident, and wherein the above switching is performed by a voltage signal applied between the groove-shaped electrodes arranged to face each other.