Arbitrary Time-Limited Optical Pulse Processors Based on Transmission Bragg Gratings

We propose a new, general approach to implement an arbitrary linear optical pulse processing operation, generally requiring a nonminimum phase spectral response, using a minimum-phase optical filter. This approach is valid for implementing any desired operation, as long as it can be limited over a prescribed time window, such as for arbitrary short pulse processors or reshapers. The proposed concept is particularly interesting for the design of optical pulse processors based on fiber/waveguide Bragg gratings (BGs) operating in transmission, enabling us to overcome the processing bandwidth limitations of their reflective counterparts. In particular, processing speeds in the THz range can be achieved using readily feasible grating apodization and chirp profiles. The approach is numerically demonstrated through the design of a relevant nonminimum-phase linear pulse processor, a real-time photonic Hilbert transformer, with an unprecedented 1.5-THz bandwidth, based on a feasible linearly chirped fiber BG structure.