SU701323A1 - Planar acousto-optical line of adjustable signal delay - Google Patents

Description

(54) PLANAR ACOUTO-OPTICAL LINE OF ADJUSTABLE SIGNAL DELAY

It contains a dielectric lanar thin-film waveguide of the optic range 1, absorber of bushy wills 2, planar dillectric lenses 3,4, changes in the effective thickness made by the wavelength of the film waveguide, the opposite-side causative agent of the 5 acoustic surface waves, operating in the frequency band of the adiosignal signal processing, a planar photodetector 6, an absorber of acoustic waves 7, a planar scanner 8, which served for angular scanning with an optical beam in the plane of a thin film LNVOD (as an example in the drawing it is depicted as an acousto-optic Bragg deflector with a causative agent of 8 a acoustic waves of a pin-pin type, a generator of 8 b sinusoidal oscillations with a smooth electrically controlled frequency tuning and an absorber 2) surface (as an example in the drawing, it is depicted as a diffraction grating),

The device works as follows.

A video signal S. (t) to be processed is input to the driver 5. It excites a traveling acoustic surface wave, which, in the form of a column with a width determined by the dimensions of the exciter 5, propagates along the thin-film waveguide and is absorbed in the load 7. From a coherent light source (e.g. laser) the optical wave beam is converted into surface optical-wave by a converter 9 And it is fed to the scanner 8, where there occurs a deviation of it by some angle depending on the frequency of the control signal arriving at the interdigital exciter 8 a from the generator 86.

Rejected by the scanner 8, a beam of optical surface waves enters a planar lens 3, the focus of which coincides with the center of intersection of the optical beams coming out of the scanner 8 at equal angles of oscillation. As a result of the arrangement of the lens 3 thus selected, the beams of optical surface waves that have passed through the lens of different frequencies in a controlled oscillator 8 b, further propagate collinearly. From the output of the lens 3, optical surface waves at the Bragg angle is fed to a column of acoustic surface wave excited by the pathogen 5, it diffracts i on it and passes through the lens 4. Behind the lens 4 at a distance

A photodetector 6 is placed equal to its focus. As a result of this mutual arrangement of the lens 4 and the photodetector 6, at any frequency of the control signal of the generator 8b, the diffracted beams of optical surface waves after passage of the lens 4 fall into the photodetector b, where they are recorded as the output signal S ( t + t). The delay time of the video signal C is determined by the place of interaction of the optical and acoustic surface; The further away the beam of optical surface waves is from the exciter 5, the later the input signal S (t) will lead to diffraction of the beam of optical / 5 surface waves and the greater will be the value of C. The limits for adjusting the delay time d T are determined from the following expression. ,

0 t

where L is the linear movement of the beam

optical surface. waves along a column of acoustic waves, depending on the ska frequency response. 8, V is the propagation speed 5 of the surface acoustic wave from the exciter 5.

The proposed device is fully implemented by methods of integrated technology. 0

Claims (2)

1. Gudzenko A, I Acousto-optic interactions in planar optical waveguides and devices on. their basis. Foreign electronics, t 9, 1976, p. 55. 2.Anderson D.B., An Jntegrated Optical Approach to the Fouries Trans0 forura. IEEE JornsiB of. Quantum EBe.ctronics Q E. - 13, No. 4, aprit 1977, p. 268 I (prototype) I.