SU1327698A1 - Method of switching optical channels - Google Patents

Abstract

The invention relates to optical communication technology. The purpose of the invention is to reduce the level of crosstalk between channels. For this, the stable positions of the onT i4ecKHX channels are ensured by the acousto-optic interaction of each optical beam (2) with the corresponding acoustic-wave 4 (5). Switching the optical channels is carried out by acting on the beams with 1.2 acoustic waves 8.9 of a different frequency. Wave propagation direction 8. and 9 forms, with the direction of propagation of the corresponding optical beams Is2, the angle that satisfies the Bragg matching condition, 2 Il. c (o

Description

1. П27698

The invention relates to the technique of optical communication and information processing. N can be used to create acousto-optical switches of type 2x2,

The circuit of the invention is to reduce the level of crosstalk between channels.

2

The angle y, between the directions of waves 4 and 5 is set to

  1 + 0g

Ut - 2

For switching the channels, the beams 1 and 2 in the area of their intersection are affected by two other acoustic systems. To this end, both are stable polo. i (j and mi waves 8 and 9, having the optical signal frequency of the optical channels providing f j equal to. C4et Bragg diffraction v i and + e

of each optical beam with respectively - f -, - sin | --- g- - | . An acoustic wave in an acousto-optic medium, and the switching of the beam is 15. These waves, like waves 4 and 5, are alternately connected in the medium in the plane of the corresponding waves,.

Fig. 1 shows the optical and acoustic distribution scheme.

weighty waves of the proposed method; in fig. 2 - schematically depict a planar KoMMytafopi implementing this method,

The switching of optical channels is carried out as follows: Two beams i. and 2 lights are directed at a selected angle. The angle is passed to the other into the austo-optic medium. In the absence of solid waves, these are after the beams are redistributed and 2. The wave is directed at an angle / g to the direction of propagation of the beam 1, and wave 9 - at an angle to the direction of propagation of the beam 2, where p is the Bragg angle for waves 8 and 9, the angle j between the directions of waves 8 and 9 is set to

  in, -vg

with

The impact of acoustic waves 4 n 5 stop.

These propagate without direction (cooTBetCTBeKHo are directions I and 2). When both current S current 3 is interfered by their intersection of the current light wave 4 and 5, an acoustic interaction of each beam KA with the corresponding acoustic wave, namely the beam I with wave 4, beam-2 with wave-OH 5. At the same time, the sort-on 4 propagates at an angle of 90 o / k to the direction of propagation of the beam i a 5 — at an angle of 90 + + to the direction of propagations of beam A 2, where the Bragg angle is these wills. Distracted part

The beam 1 propagates, along the lines of g 4ig, 2. The device contains 6, and diffracted scattered on the substrate 10. a film of 2 software direction 7. To the direction of the optically transparent crystal, 6 and 7 correspond output channels. The angle between them is equal to b, and depends on the intensity of acoustic waves 4 and 5. (which is set by

50

A high acousto-optic quality, for example, from niobate lithium, In film 1, two flat lenses 12, 13 are made, which are located at a double focal distance, one from another, and at a focal distance F, each from the nearest edge of the film 11, -C With one the end of the film 11 is connected via matching elements 14, the input single-mode fiber optic fibers 15, 16, C opposite the ends of the film 1I are connected through matching

equal to

, 2V. I e-bg I

1.-GG

where V is the propagation velocity

acoustic wave; - length of light in the environment.

2

The angle y between directions 4 and 5 is set to

  1 + 0g

Ut - 2

These waves, like waves 4 and 5, propagate in the medium in the plane

beam propagation and 2. Wave 8 is directed at an angle / g to the direction of beam propagation 1, and wave 9 - at an angle to the direction of beam propagation 2, where p is the Bragg angle for waves 8 and 9, Angle j between wave directions 8 and 9 set ryvnym

  in, -vg

with

The impact of acoustic waves 4 n 5 stop.

as a result of the acoustic interaction, the diffracted part of the beam 1. will propagate in the direction of 7, and the diffracted part of the beam 2 in the direction of 6, thereby achieving a switching of xsamels. Since the output channels 6 H 7 are spatially separated from the direction of propagation of diffused radiation, the influence of the latter on the level of crosstalk between the channels,

A specific example of a device that implements yes: this method is given in

4g, 2. The device contains a film of optically transparent crystal disposed on a substrate, about -.-

In the film 1, two flat lenses 12, 13 are made, located at double focal distance one from the other and at the focal distance F each from the nearest edge of the film 11, with one end of the film 11 are connected via matching elements 14 input single-mode optical fibers 15, 16, C opposite the ends of the film 1I are connected through matching

elements 14 single-mode output LEDs J7, 18, On the surface of the 1I film on one side of the optical axis 00 of the switch there is a pair of interdirectional transducers of surface acoustic waves (SAW) 19 and 20, on the other side - a pair of interdirectional SAW transducers 21 and 22, The transducers 19 and 21 are tuned to the frequency fj, the transducers 20 and 22 to the frequency f. All transducers are oriented so that their acoustic axes intersect at point 3, coinciding with the focus of lenses 12 and 13, while the acoustic axes of transducers 19,

21 intersect at an angle y, the acoustic axes of the transducers 20,

22 - at an angle j- ,, the distance L between the input fibers 5, 16 and

LJ between the output fibers 17, -18 are determined by the selected values of the angles 0,, 0J and the focusing distance F of the lenses 12,13. These distances are calculated using the formulas

L, 2Ftg.

L 2Ftg;

The numerical values of the parameters of the device are as follows: The dimensions of the substrate are 16x2x10 mm. The diameters of single-mode fibers 15,16,17,18 are 5 µm, the width of the optical channels in the interaction region is 300 µm. The value of F is 4 mm (for Lo µm). The distance L is 288 microns, the distance Lj is 138 microns, Molds 19 and 21 are tuned to a frequency of 250 MHz, operate on the second harmonic and have an aperture of 4.5 mm, Transducers 20 and 22 tuned 1y to a frequency of 700 MHz, operate on seventh harmonic and have an aperture of 1.7 mm, the magnitude of the angle is 0, equal to 4.13, the magnitude of the angle QI is 1.97, the magnitude of the angles

 and 3.05 ° and 1.08, respectively. Acoustic wave from

converter 19 propagates at an angle to beam 1 equal to 90 ° + (90.54, the same angle between the wave from converter 21 and beam 2,

698

The angle between the wave from the transducer 20 and the direction of the beam (as well as between the wave from the transducer 22 and the direction of the beam 2) is 90 + / 91.53,

Formula

acquisitions

The method of switching optical channels, including the direction of two beams of optical radiation in an acousto-optical environment at an angle to one another and the WHO

action on both beams in their area

the intersection of one acoustic wave with a frequency propagating in an acousto-optic medium in the plane of propagation of both beams of optical radiation at an angle to the direction of propagation of one of them, satisfying the condition of Bragg synchronism, characterized in that, in order to reduce crosstalk, they additionally affect to both optical beam beams in the region of their intersection by another acoustic wave of the same frequency fj propagating in the acousto-optic medium in the plane of propagation boih optical beams at an angle to the direction of the other beam of optical radiation satisfies - yuschim Bragg matching condition, and for switching optichesk5: x and on

They replace the effects of these acoustic waves on two other acoustic waves of the same frequency f, different from the frequency of the first two acoustic waves, the second two acoustic waves propagating in an acousto-optical medium in the plane of propagation of both optical beams so that the direction of propagation of one of the they are formed by an angle that holds the Bragg matching condition for the frequency f the direction of propagation of one optical beam, and the direction is distributed other wave forms an angle satisfying the condition yuschy brzggovskogo synchronism for the frequency f with the direction of propagation of another optical beam.

Phage.1

P

10 13

fig.g

Compiled by N. Bogdanov Editor T. Loshkareva Tehred I. Popovich Corrector A, Tsko

Order 4665 Circulation Subscription

VSIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, 4/5

Production and printing company, Uzhgorod, st. Project, 4

Claims (1)

canapies A method for switching optical fishing, including the direction of two optical radiation into an acousto-optic medium at an angle to one another and the impact on both beams in the region of their intersection of one acoustic wave with a frequency propagating in an acousto-optic medium in the plane of propagation of both optical beams at an angle to the direction propagation of one of the nicknames satisfying the Bragg synchronism condition, characterized in that, in order to reduce crosstalk, they additionally affect both beams optical radiation in the region of their intersection by another acoustic wave of the same frequency f _f propagating in an acousto-optic medium in the plane of propagation of both optical beams at an angle to the direction of the other optical radiation beam satisfying the Bragg condition, and for switching optical channels, replace the action with the indicated acoustic waves on exposure to two other acoustic waves of the same frequency, different from the frequency of the first two acoustic waves, the second two acoustic waves propagate in an acousto-optic medium in the plane of propagation of both optical beams so that the direction of propagation of one of them forms an angle satisfying the Bragg condition for frequency with the direction of propagation of one optical beam, and the direction of propagation of the other wave forms an angle that satisfies the Bragg condition synchronism for frequency f ₂ with the direction of propagation of another optical beam.