title: FPGA-based phase control of acousto-optic modulator Fourier synthesis system through gradient descent phase-locking algorithm.
abstract: We present a new application of the stochastic parallel gradient descent (SPGD) algorithm to fast active phase control in a Fourier synthesis system. Pulses (4.9 ns) with an 80 MHz repetition rate are generated by feedback from a single phase-sensitive metric. Phase control is applied via fast current modulation of a tapered amplifier using an SPGD algorithm realized on a field-programmable gate array (FPGA). The waveforms are maintained by constant active feedback from the FPGA. We also discuss the extension of this technique to many more semiconductor laser emitters in a diode laser array.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Underwood
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Jones
authors.forename: Juliet T
authors.initials: JT
authors.lastname: Gopinath