Design of all-optical read-only memory

Abstract

Galois field (GF) algebraic expressions have been found to be promising choices for reversible and quantum implementation of multivalued logic. For the first time to our knowledge, we developed GF(4) adder multivalued (four valued) logic circuits in an all-optical domain. The principle and possibilities of an all-optical GF(4) adder circuit are described. The theoretical model is presented and verified through numerical simulation. The quaternary inverter, successor, clockwise cycle, and counterclockwise cycle gates are proposed with the help of the all-optical GF(4) adder circuit. In this scheme different quaternary logical states are represented by different polarized light. A terahertz optical asymmetric demultiplexer interferometric switch plays an important role in this scheme.

Study on the instantaneous frequency deviation of pulses switched from semiconductor optical amplifier–assisted Sagnac interferometer

“…4 Among the main existing types, the SOA-assisted Sagnac 5 /terahertz optical asymmetric demultiplexer 6 effectively combines fast switching speed up to 100 Gb/ s, low energy requirement, jitter and noise tolerance, intrinsic stability to environmental fluctuations, and the ability to be cascaded with integration potential and overall practicality. Owing to these remarkable properties, it has been possible to successfully exploit the switching behavior of this module under pulsed operation 7 for signal processing exclusively in the optical domain and to demonstrate serial Boolean logic, 8 clock recovery, 9 demultiplexing, 10 binary-to-quaternary encoding/decoding, 11 multivalued logic, 12 data format conversion, 13 regeneration, 14 sampling, 15 header and payload separation, 16 buffering, 17,18 parallel Boolean logic and arithmetic operations, 19 modular arithmetic, 20 binary addition and subtraction, 21 and flip-flop memories. 22 One common characteristic of the aforementioned demonstrations, which has also affected the content of the relevant theoretical works, 5,23-32 is that they have focused on the intensity rather than on the phase transmission function of the switch.…”

“…35,36 Furthermore, provided that it acquires the proper profile and magnitude by controlling the interferometric process while its counterpart introduced in a dispersive medium has the opposite direction, then their combination can compress the pulse on which it was initially imposed. 37 This technique could be exploited when the output from such a switch sets the operational state of another, identical one 11,12,[19][20][21][22]38 or is fed back to itself. 17,18 Under such circumstances, the narrower the gating pulses are, the better is the shape of the window inside which switching is possible 27 and hence the overall performance.…”

“…It should be noted that the main motives for carrying out the theoretical treatment on the SOA-assisted Sagnac switch have been the availability of related state-of-the-art only for this module, 34 the recent intense interest that it has attracted as core building unit in multistage interconnection architectures of enhanced functionality, 11,12,[19][20][21][22] and the authors' desire to preserve the continuity with their earlier relevant work. 4,5,8,17,32,39 Thus, there is not an absolute reason or restriction for this choice, and the method of analysis adopted here can also be followed for its counterpartsnamely, the Mach-Zehnder interferometer ͑MZI͒ 40 and the ultrafast nonlinear interferometer ͑UNI͒.…”