title: Ultrafast optical pulse digitization with unary spectrally encoded cross-phase modulation.
abstract: A method to digitize the intensity of ultrashort laser pulses for high-speed optical signal processing is described. This digitization was based on the spectral broadening of a weak probe (carrier) pulse by a more intense pump (signal) pulse through the nonlinear optical process of cross-phase modulation (XPM). The signal pulse intensity was varied to generate different spectral widths that can be encoded into digital form. Using a 50-ps time-divided multiplexing pulse train with a waveguide splitter, combiner, and an array of fibers with variable lengths, a unary XPM encoding approach is demonstrated. The spectral encoding scheme can be used to achieve a 5-GHz sampling rate at a 16-level accuracy.
authors.forename: P P
authors.initials: PP
authors.lastname: Ho
authors.forename: Q Z
authors.initials: QZ
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.forename: Q D
authors.initials: QD
authors.lastname: Liu
authors.forename: R R
authors.initials: RR
authors.lastname: Alfano