Optical delay dynamics and its applications

Ishikura, Baba, Kuramochi +1 more

Andrea Ivano Melloni, Francesco Morichetti, Filippo Persia +3 more

The possibility of dynamically controlling the speed of light can be extremely useful in all the optical applications where a variable delay is needed, such as bit and frame synchronization and optical storage. To this aim, coupled resonator slow-wave structures (SWSs) represent a promising approach to slow down the propagation of optical signals with as large bandwidths as required by optical communication systems. We show that by suitably setting the rings' resonances, SWSs can act efficiently as tunable delay lines, with the overall time delay being continuously adjustable from zero to a maximum value, typically limited by the effects of loss and dispersion. Every ring of the structure can be used as an optical gate and optical pulses can also be trapped and released by the SWS, so as to realize an optical memory or buffer. A time delay of 300 ps and a slowing ratio of 7.5 over a 3.3 GHz bandwidth are experimentally demonstrated in SWSs realized in silicon oxynitride technology

Jan Peřina

Stephen Lynch, R.A. Alharbey, Hanan Ali Batarfi +1 more

Optical bistability (OB) for a homogeneously broadened two-level atomic system in a ring cavity is investigated within and without the rotating wave approximation (RWA) using nonautonomous Maxwell–Bloch equations subject to a time delay. It is shown that the dynamics both within and without the RWA are susceptible to the introduction of time delays in the differential equations. A range of instability scenarios are found as certain parameters are ramped up and down and these can affect the bistable operation of the physical devices. However, the introduction of a time delay can also result in an important positive application; for the first time, as far as the authors are aware, it is shown that a type of butterfly hysteresis can occur in the fundamental component, which is a relatively strong output signal, and may be desired in optical signal processing.

Sami A. Shakir

修一 村上, Shuichi Murakami