All optical memory

Dieter Pohl

前田 武志

Y. Liu, M.T. Hill, Daan Lenstra +4 more

An all-optical memory with three states is presented. The optical memory is realized from three-coupled identical nonlinear polarization switches. The state of the optical memory is determined by the wavelength of the memory’s output light. In each state, only one wavelength is dominant. The concept is explained and experimental results are presented that demonstrate that a contrast ratio of over 20 dB and a switching power of around 8 dBm can be obtained. This concept can be extended for an all-optical memory with a large number of states, which is crucial to realize 1×N all-optical packet switches.

Rachel Pei Chin Won

Keishi Habara

Abstract To realize a high‐speed time division optical switching network, optical bistability devices including optical memory are important. In this paper, a bistable laser‐diode memory made of an APD, an LD and an optical feedback circuit is studied from the point of low set power and high speed. To attain a low set power, the effect of spontaneous emission of an LD cannot be neglected. Therefore, the input and output characteristics of an optical memory are studied including the spontaneous emission coefficient. Next, the response speed at a low input power is studied and the relationship between the response speed and the optical memory design parameters is derived. The input‐output characteristics and the response speed are verified with an experimental circuit. Finally, a high‐speed optical memory with a low set power is fabricated. The results of operating experiments of optical memories in an optical switching network are described.