Ring-Laser Optical Flip–Flop Memory With Single Active Element

Abstract

Abstract-We present a novel optical flip-flop configuration that consists of two unidirectional ring lasers with separate cavities but sharing the same active element unidirectionally. We show that in such a configuration light in the lasing cavity can suppress lasing in the other cavity so that this system forms an optical bistable element. Essential for obtaining the bistability is the presence of an additional feedback circuit that is shared by both lasers. We show experimentally that the flip-flop can be optically set and reset, has a contrast ratio of 40 dB and allows low optical power operation. We also present a model based on roundtrip equations. Good agreement between theory and experiments is obtained.

All-optical Flip-flop based on Optical Beating and Bistability in an Injection-locked Fabry-Perot Laser Diode

“…These techniques for the set and reset operations have recently been extended to such uses as architectures for a coupled ring laser, coupled Mach-Zehnder interferometers, and coupled nonlinear polarization switches [5][6][7][8]. In addition, an AOFF using two coupled, single-mode FP-LDs at high rate with high on-off contrast ratio has been reported [9].…”

Proposal of optical flip-flop operation between two phase states with a single SOA and a feedback loop

“…Various device architectures have been studied, which include a single DFB laser [1], coupled two semiconductor optical amplifiers (SOAs) [2], [3], a single SOA in two different wavelengths [4], a single SOA in two oppositely propagating lights [5], a single SOA-MZI with a feedback loop [6], [7]. The authors have also proposed a flip-flop consisting of a single SOA operated in two polarization modes [8].…”

Multistate optical memory based on serially interconnected lasers

“…Many types of optical memories have been explored, which all have in common that optical storage elements with two states can be realized [3]- [7]. The existence of multistable optical logic building blocks is interesting for applications in telecommunication systems, since they have potential to switch multiple packets.…”

“…This concept requires that each laser is connected with all the other lasers in the memory, making the number of interconnections large and the operating power high. The optical memory concept, based on coupled ring lasers presented in [7] allows extension into more states, but its output is oscillating, making the concept hard to apply in more sophisticated systems.…”