Accession Number : ADP008149

Title :   Soliton-Dragging Logic Gate with an Erbium-Doped Fiber Amplifier,

Corporate Author : AT AND T BELL LABS HOLMDEL NJ

Personal Author(s) : Islam, M. N. ; Soccolich, C. E. ; Hong, B. J. ; Chen, C. J. ; Simpson, J. R.

Report Date : APR 1992

Pagination or Media Count : 2

Abstract : We place an erbium-doped fiber amplifier (EDFA) in th interaction region between orthogonally polarized control and signal pulses to widen the timing window for a soliton-dragging logic gate (SDLG). In general, the two inputs to an SDLG must overlap within a pulse width to obtain a time shift at the device Output However, by introducing gain during the interaction between the two pulses, we can asymmetrize the walk-off and, thereby, broaden the timing window. To understand the expected timing broadening, we first solve numerically the coupled nonlinear Schrodinger equations. In the simulations we assume a several walk-off length section of moderately birefringent fiber followed by a discrete amplifier and then a longer length of moderately birefringent fiber. The calculated shift of the control pulse AT (with and without the signal) versus initial separation between pulses = (Delta t sub signal t Signal- T sub control) when the same moderately birefringent fiber is used on both sides of the amplifier and the control pulse is along the fast axis. Curves are plotted for a discrete gain of 1.5 placed at 1, 1.5 and 2 walk-off lengths, l sub wo, down the fiber. We find that the timing window can be broadened, although the shape is quite asymmetric. The peak near Delta t=O arises from the interaction between the control and signal pulses at the beginning of the first fiber. A second feature (at delta t <O) arises from collision of the pulses in the amplifier, and its magnitude is proportional to the increase in the signal amplitude (i.e. proportional to the gain minus one).

Descriptors :   *AMPLIFIERS, *LOGIC ELEMENTS, *FIBER OPTICS, *SYMPOSIA, AMPLITUDE, CONTROL, EQUATIONS, ERBIUM, SOLITONS, BIREFRINGENCE, SCHRODINGER EQUATION, OPTICAL PUMPING, POLARIZATION.

Subject Categories : Fiber Optics and Integrated Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE