All-Optical Clocked Flip-Flops Exploiting SOA-Based SR Latches and Logic Gates

Abstract

Abstract. All-optical flip-flops are key components of photonic digital processing in next generation optical network and computing. In most digital applications, signal synchronization with a reference clock is a basic feature. In this paper, an entire set of all-optical clocked flip-flops, including SR, D, T, and JK types is proposed and demonstrated, each employing a single SR latch and optical logic gates previously introduced in literature. The bi-stable element is based on gain quenching mechanism between SOAs of two coupled fiber ring lasers. Three logic gates are carried out by exploiting four wave mixing (FWM) and cross gain modulation (XGM) nonlinear effects in SOA. Different flip-flop functionalities are obtained by adding one of the logic gates, or a combination of them, to the latch scheme. Performance evaluation in terms of extinction ratio demonstrates the effectiveness of proposed schemes. Speed limitation of flip-flop operation is also investigated and photonic integration is identified as a feasible solution to increase the operation speed beyond GHz.

Design and simulation of all optical shift registers using D flip‐flop

“…The DFF behaves as a basic memory cell. 8 It is called as a delay flip flop because the D input state is taken by Q output. The input that appears at the D input will appear at output Q in the presence of active clock signal which is optical in nature and is generated similar to the input signals.…”

“…The DFF stores the value present on the data line. The DFF behaves as a basic memory cell . It is called as a delay flip flop because the D input state is taken by Q output.…”

All‐optical clocked D flip‐flop memory using a hybrid integrated S‐R latch

“…In previous work [6], a synchronous all‐optical D flip‐flop has been implemented using two coupled fiber ring lasers and additional logic gates exploiting the nonlinear effects of SOAs. The technology behind is not uniform and presents serious speed limitation.…”

Experimental evaluation of all-optical asynchronous and synchronous memories

“…Different technologies have been proposed to provide optical buffering such as the use of, a SOA based MachZenhder interferometer with a feedback loop [3], two coupled identical laser diodes [4], fiber-delay lines [5], two coupled fiber ring lasers [6] or two coupled MZI-SOA [7].…”