All-Optical Phase Memory Circuit Based on Two Coupled Lasers and External Optical Injection

• Published in: IEEE journal of selected topics in quantum electronics Vol. 29; no. 2: Optical Computing; pp. 1 - 11
• Main Authors: Lerber, Tuomo von, Lyubopytov, Vladimir S., Ylinen, Lauri, Lassas, Matti, Kuppers, Franko
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: coupled oscillator systems; Electric fields; Lasers; Optical bistability; Optical buffering; Optical communication; optical computing; Optical coupling; optical injection locking; Optical memory; Optical memory (data storage); Optical polarization; Optical pulses; Optical signal processing; Semiconductor lasers; Signal processing; Wave propagation
• ISSN: 1077-260X; 1558-4542
• DOI: 10.1109/JSTQE.2023.3239167

We propose a volatile static all-optical memory capable of storing phase information of a slowly-varying electric field. The scheme and its realization (a memory circuit) are based on two mutually coupled lasers subject to external optical injection. The proposed circuit has a single optical input for write and hold operations and two opposite-sign outputs for reading the memory. The proposed circuit operates with a single wavelength of light, a single direction of propagation, and without a need to switch the state of polarization. We prove mathematically that the proposed arrangement has equilibrium points that may discreetly quantify and store the phase in a bistable manner. The circuit is studied numerically for solid-state and semiconductor lasers with zero and non-zero linewidth enhancement factors, respectively. Simulations based on a rate equation system confirm the essential findings. Using typical parameters of a semiconductor laser and optimizing for a possibly wide range of operation, the write-read operations were simulated using PRBS-9 at the rate of 1 Gb/s with negligible errors. The proposed circuit will enable integrated memory implementations for future all-optical signal processing and computing systems.