SU1509809A1 - Multistable optical element - Google Patents

Abstract

The invention relates to optoelectronic computing devices and can be used as a logical element with a variety of stable states, an analog-to-digital converter or an optical memory element. The aim of the invention is to increase the speed and simplify the identification of the states of an optical multistable element. The device contains a tunable single-frequency laser, a collimator, a Fizeau multi-beam interferometer and a line of photodetector elements sequentially located on the optical axis. The increase in speed is due to the absence of a feedback circuit in the device, in which delays of the signal being processed are inevitable. Simplification of the identification of states is due to the fact that instead of measuring the level of the output signal, it is sufficient to determine the number of the photodetector element of the ruler, the output of which is a single signal. 1 hp ff, 4 ill.

Description

The invention relates to an optoelectronic computing technology and can be used as a logical element with a variety of stable states, analog-to-digital. an inverter (ADC) or an optical memory element.

The aim of the invention is to increase the speed and simplify the identification of the states of an optical. Multi-stable element.

Figure 1 shows the functionalities on the optical layout of a multistable element; Fig. 3 shows the arrangement of the photodetector array with respect to the interference order; Fig. 3 shows the amplitude dependence and. of the output signal of the multtaoo X.

the amplitude amplitude element and the input signal} in Fig. 4 is a functional optical circuit of the ADC based on a multistable element.

The optical multistable element (figure 1) contains a tunable single-frequency laser sequentially located on the optical axis.

F

00

about f

made in the form of the control element 1 and the single-frequency laser 2 itself, the collimator 3, the Fiao multi-beam interferometer 4 n line of 5 photodetector elements.

 In the private version, the tunable single-frequency laser is made in the form of a semiconductor injection laser with a pump current modulator (Fig. 4).

The device works as follows.

The input signal is fed to the input of the multistable element and, through control element 1, changes the frequency I of the laser 2, in proportion to the amplitude Ug,. The radiation of a single-frequency laser 2 passes a collimator 3 and enters a multipath Fizo 4 interferometer, the output of which forms a system of equidistant interference order whose position along the x axis depends on the frequency (wavelength) of the laser radiation (axis X perpendicular to the edge of the multipath interferometer Fizeau 4 lies in the plane of localization of the interference orders (Figs. 2 and 3). The interference pattern is recorded by a ruler of photodetector elements 5. Depending on the position of the interference pores For example, the i-th photo-direct element will be illuminated along the Y axis (Fig. 2). Accordingly, the output signal at the i-th output of the multistable element will appear.With a change in the amplitude and Q input signal in a certain range of values, the interference order will remain within the apertures of the i-ro photo-receptive element, which corresponds to the i-th stable state of the device.With a change in the amplitude U over the entire range of the linear dependence of the frequency of the laser 2 on the value of Ugy, the interference order passes the apertures of all N mnyh elements. As a result, the dependence of the output signal of the device on the magnitude of the input signal has the form shown in FIG. Each stable state of the device corresponds to the appearance of the output signal at the output of a certain photo receiving element.

The limiting number of states of the Nucons device depends on the sharpness of the interferometer F, in particular N.,

2F.

For the transition from the first state to the last, the wavelength of the single-frequency laser 2 is tuned to the value of l equal to the dispersion of the Fizeau multi-beam interferometer 4

l

  -jr, where 1 is the length of the internferometer. In particular, for a semiconductor injection laser (0.67–0.78 µm), the value is 1–0.01 m and, accordingly, l is 0.3–0.2 A, for which it is necessary to change the pump current by 4 mA.

For the case of an ADC (Fig. 4), the outputs of the multistable element are connected to the corresponding inputs of the memory cell, which makes it possible to compare

defined code for each stable state of the device (see table).

25

State

I

The number in the cell

five

0

five

0

five

The increase in device speed compared to an optical multi-stable element containing a controllable element in the composition of an interferometer that receives a signal from an output photodetector is due to the absence of signal delays, which are inevitable due to the specified feedback output photodetector - control element .

Simplification of identification of device states is caused by the fact that instead of measuring the output signal level values, it is sufficient to determine the number of the photodetector element at the output of which a single output signal appears.

In the case of a particular embodiment of a tunable single-frequency laser in the form of a semiconductor injection laser with a pump current modulator, the switching state of the device state is additionally reduced to a value of the order (with F 20, N 40 and a photodetector element speed of about c).

Claims (1)

1. Optical multistable element containing a controllable light source, a collimator, an interferometer and a photodetector arranged in series on the optical axis, characterized in that, in order to increase speed and simplify the identification of the states of a multistable element, the control light source is made in the VID of a tunable single-frequency laser , the interferometer is made in the form of a multibeam interferometer Fizo and a photodetector - in the form of a line of photodetector elements, located perpendicular to the optical th axis in the plane of localization of the interference orders, between the neighboring of which there are N photodetector elements, where N is the number of states of the multistable element, and the outputs of the line of photodetecting elements form the output of the multistable element. 2, an element according to claim 1, characterized in that the tunable single-frequency laser is made in the form of a semiconductor injection laser with a pump current modulator. Bwd - /and - dsod tt ± 5a t / fcix urn (i) N . / “Ab and, 0ui2 e .J f 5 ,