A perturbative and numerical analysis reveals the conditions for suppressing the interaction between adjacent phase-locked solitons in a soliton optical memory. This may permit the permanent storage of a soliton bit pattern in a diffractive or dispersive ring cavity.
We demonstrate the operation of an all-optical buffer based on temporal cavity solitons stored in a nonlinear passive fiber ring resonator. Unwanted acoustic interactions between neighboring solitons are suppressed by modulating the phase of the external laser driving the cavity. A new locking scheme is presented that allows the buffer to operate with an arbitrarily large number of cavity solitons in the loop. Experimentally, we are able to demonstrate the storage of 4536 bits of data, written all optically into the fiber ring at 10 Gb/s for 1 min.
Optical storage devices are essential elements of future ultra-high bit-rate fiber communications systems in which they will find applications to various vital functions. Pulse pattern storage has been demonstrated in various fiber loop devices [1] that involve pulse control techniques in order to provide timing stability of the bit patterns. Most of these stabilization techniques are based on electrooptic modulation which limits the bit rates to a tenth of Gb/s. Moreover, erasing the data in these storage fiber loops requires switching off the system elect rooptically. Individual bit addressing is therefore impossible, which considerably restricts the functionality of the devices. We investigate here the possibility of developing a new type of all-optical fiber loop storage device. This device consists of a simple nonlinear passive fiber ring resonator synchronously and coherently pumped by a cw mode-locked train of ultrashort pulses. It is well known that this system exhibits rich nonlinear dynamics, in particular, optical bistability which is a feature naturally suited for applications to optical storage. However, erasing the data in an optical bistable element requires to switch off the holding beam and is therefore not practical. Recently, Haelterman et al. [2] have studied the polarization dynamics of nonlinear dispersive ring cavities with cw pump and have shown that these devices exhibit a polarization symmetry breaking characterized by a pitchfork bifurcation. This feature can be applied to the development of a set-reset flip-flop all-optical fiber loop pulsed memory. This work aims at presenting the results of a preliminary investigation of such a storage device.
Recently we have shown that stable soliton-like pulse propagation over ultra-long distances is possible in a nonlinear fiber line in which linear loss is balanced by periodic phase-sensitive (parametric) amplification.1 In such a line the length scale over which pulse evolution occurs is significantly increased beyond a soliton period because of the attenuation of phase variations across the pulse’s profile by the amplifiers. Here we examine the effects of quantum noise in the context of a storage ring for a bit stream of soliton-like pulses. We show that the one’s (soliton pulses) are asymptotically stable and the noise on the zero’s of the bit stream (absence of a soliton) is bounded. Moreover, we present evidence that the soliton-soliton interaction and Raman self-frequency shift are efficiently suppressed by the phase-sensitive amplifiers (PSA’s). The effects of direct timing noise and cubic dispersion in the fiber could also be decreased by using a pulsed pump (gain modulation) for the PSA’s.