Erbium-ytterbium-doped fiber absorption and fluorescence are exploited to realize an optical bistable device. An all-optical flip-flop with 10-ns transition time, 18.48-nJ set, and 19.82-nJ reset energies, is experimentally demonstrated. The possibility to reach an extinction ratio of more than 8 dB is demonstrated as well
Operating principle for a flip-flop memory cell based on erbium-doped devices is presented. A complete model for memory dynamics is introduced taking into account, at the same time, for memory writing, reading, and erasing. Simple equations are found relating writing, spontaneous and stimulated erasing times to device physical parameters, signals wavelength and power. In principle, for example, increasing writing and erasing energies at the appropriate wavelength it is possible to dramatically reduce transition times. Extinction ratio (ER) is also determined as a function of host medium, and signals properties. An optimization technique is proposed for erasing signal design in order to guarantee maximum ER. Numerical example are provided for Er and Er-Yb doped fibers whose doping ion density is rho = 1.1413middot1024ions/m3, and 2.0 middot1025ions/m3, respectively. Finally, an experimental demonstration giving an Er higher than 5 and 16 dB for the two fibers, respectively, is provided and discussed.