All-optical Processing Schemes Research Articles

Stimulated Brillouin Scattering in Photonic Integrated Circuits: Novel Applications and Devices

The last few years have seen major progress in harnessing on-chip photon-phonon interactions, leading to a wide range of demonstrations of new functionalities. Utilizing not only the optical response of a nonlinear waveguide-but also acoustic resonances-enables the realization of microwave devices with unprecedented performance, otherwise hard to achieve in all-optical processing schemes or electronically. Here, we overview on-chip stimulated Brillouin scattering (SBS) with special emphasis on microwave sources and microwave signal processing schemes. We review the different material platforms and structures for on-chip SBS, ranging from chalcogenide rib waveguides to hybrid silicon/silicon-nitride structures, high-Q photonic-phononic silica microresonators, and suspended silicon nanowires. We show that the paradigm shift in SBS research-from long length of fibers to chip-scale devices-is now moving toward fully integrated photonic-phononic CMOS chips.

Impact evaluation of the SOA spontaneous emission in ultrafast all-optical processing schemes

In ultrafast all-optical signal processing schemes based on nonlinear effects in SOAs, the impact of the device spontaneous emission noise is not negligible. Therefore a numerical extended model is developed in order to predict SOA noise behaviour. The proposed tool takes into account all the gain recovery dynamics, the current-induced gain saturation, and the gain spectrum dependence on the injected current. The noise spectrum at the output of the device is investigated as a function of the injected current and of the input power, and the numerical results are experimentally validated. The importance of the ASE introduction in the numerical analysis of the SOA-based schemes for ultrafast all-optical processing is demonstrated studying two particular applications. In particular, the effects of high detuning FWM and of XGM are analysed in the presence and absence of ASE noise.

All-optical processing by fiber delay and four-wave mixing of high-bit-rate nonreturn-to-zero signals for timing extraction by optical injection locking

We report an all-optical processing scheme which generates a strong spectral component at the bit rate frequency of a high-speed nonreturn-to-zero data stream. The processed signal can be used for timing extraction by direct optical injection locking. The scheme is based on multiplying the data signal by its delayed replica. A dispersion compensating fiber serves as a delay line and the multiplication is performed by four-wave mixing in a dispersion-shifted fiber. Simulated results and experimental confirmations are demonstrated.