Applications of superstructured fibre Bragg gratings in all-optical signal processing

Abstract

The possibility of combining pulse shaping technology with various nonlinear optical switching devices can be beneficial in enhancing the overall system functionality. Most works on short-pulse communications utilize either Gaussian or sech2 pulse shapes, which are readily generated through conventional pulse generation techniques. However, important recent advances in various pulse shaping technologies have allowed the properties of well-defined pulse waveforms to be manipulated and transformed into other pulse forms of almost arbitrary complexity. The capability to realize the optimal pulse shape required for the operation of a particular switch can be very advantageous in terms of improving its overall performance. Among the various pulse shaping technologies, the one based on superstructured fibre Bragg gratings (SSFBGs) offers a ready route to the production of in-fibre optical filters with precisely controlled frequency and phase profiles in a single continuous grating structure. SSFBGs have proven to be an extremely powerful tool for advanced photonic applications that require fine and accurate manipulation of the shape of short optical pulses, thanks to the high precision in the implementation of the superstructure phase and amplitude profiles offered by plane-by-plane grating fabrication techniques. Using this linear all-fiberized pulse shaping method, we have demonstrated the reshaping of short pulses of a few picoseconds duration into a broad range of pulse shapes, such as rectangular pulses of different pulse widths (5, 10 and 20ps) [1-3], parabolic [4-5] and saw-tooth pulses [6-7] for various all-optical signal processing applications.The talk will review some application examples of optical processing systems that combine SSFBGs for preconditioning of the incoming signals with highly nonlinear fibre (HNLF)-based switches and discuss their benefits.