Development on astable multivibrators using the combination of linear and non-linear materials as switching elements based on all optial method

Abstract

In this communication we propose a method to implement an all-optical astable multivibrator using the non-linear material based switches and logic gates. The scheme can operate in real time. The delay time can achieve ps(pico-second). The pulse duration can be made very low and may cross the THz easily by selecting proper material and laser source.The roles of switches are essential and obvious in any information processing mechanism. Different all-optical switches are already developed by scientists. Also the all-optical logic gates are developed using the combination of linear and nonlinear optical materials. Several memory devices, such as all optical clocked R-S flipflop, J-K flip flop etc., are developed using this switching mechanism of non-linear material. Here, the authors propose a new proposal to develop an astable multivibrator using NOT (Inversion) logic gate, which are all optical in nature. It is widely established that super fast computation can deal with photon easily [1][2][3] . In this connection different all-optical logic devices are already developed around the world by the last few decades [4][5][6] .Inherent parallelisms of an optical signal over its electronic counterpart can be exploited in several ways. Nonlinear optical devices come in the frontline of such ways of optical information processing. Many high-speed operations have been implemented by the use of optical non-linear material [7][8][9] . We know that many isotropic non-linear materials (such as pure silica glass, CS2 etc.) follow the refractive index relation as where n is the refractive index (r.i) of a non-linear material, n 2 is the non-linear correction term, n 0 is a constant linear r. i term and I is the intensity of light passing through the material. This helps us to understand the basic switching operation using nonlinear material with an optical signal. In Fig.1 we n = n 0 + n 2 I , have shown an optical switch. Here X and Y are the two inputs each with a prefixed intensity I, M is the mirror used to change the path, and B.S is the beam splitter or combiner. When both of the inputs are present, the refracted output will pass through O 1 channel and when any one of them is present, the output will be obtained through O 2 channel. This happens according to the above nonlinear equation and Snells' law. Now we discuss the basic operation of logic NOT gate using the combination of linear and non-linear materials and above switching mechanism.The schematic diagram of NOT logic gate can be understood also by Fig.1. Here X is the input channel and CLS represents the constant light source Y, which both have a specified intensity I 1 . The output channels are O 1 and O 2 . When the input channel X does not have any light signal i.e. at the logic state 0, then light goes through channel O 2 ;and when X is in a logic state 1, i.e. it has light with a specified intensity, then light follows the channel O 1 . To get the output of a NOT logic gate, the observer should be at the position of channel O 2 . Several all optical logic an...

An all-optical architecture of serial to parallel converter by using Kerr type of non-linear material

“…To organize the operation all the input beams should be drawn from a single coherent laser source. As the thickness of the NLM and LM are very small (≈mm), so a metre order of coherent Table 1 Truth table for AND (c) Based on this switching action several all-optical logic devices and gates have been proposed [13][14][15][16][17][18][19]. So, we have not discussed the action of these types of switches for all other logic gates.…”

A method of developing all-optical mono-stable multivibrator system exploiting the Kerr non-linearity of medium

“…Several concepts of optical digital memory devices such as alloptical clocked R-S flip-flop, astable, bi-stable multivibrator have been proposed using the above switching mechanism (i.e. variation of r.i. with I) of non-linear material [11][12][13].…”