OSCILLATION MODES OF LASER DIODE PUMPED HYBRID BISTABLE SYSTEM WITH LARGE DELAY AND APPLICATION TO DYNAMIC MEMORY

An electrooptical bistable system with a very large delay was constructed of state-of-the-art optical communication components and the self-oscillation phenomena of the system were investigated from the point of view of application as dynamical memory. Very large numbers of multistable self-oscillation modes were observed, including second order bifurcations of the 265th harmonic. The dynamical memory function was demonstrated by locking second order bifurcated modes to external clock oscillations and performing WRITE and READ of binary data sequences in the waveforms of the bifurcated modes. From the dynamical stability of the oscillations used for memory, and of the mode switching, it was concluded that the nonlinear bifurcation phenomena in this system are applicable for large capacity memory and signal processing. Spurious preferential excitation of particular harmonic modes that occurred in the system was related to the fine structure in the transfer spectrum of the open loop associated with spurious resonances in the electrooptical (E-O) modulator used as nonlinear element. It was demonstrated that missing harmonics could be recovered by pumping with small sinusoidal signals of the corresponding frequencies.