title: Real-time characterization of FM-AM modulation in a high-power laser facility using an RF-photonics system and a denoising algorithm.
abstract: FM-AM modulation of high-power lasers significantly affects laser performance. Therefore, precise measurement of the FM-AM modulation depth is necessary. The subsequent FM-AM modulation generated by group velocity dispersion when the laser pulse propagates through a fiber affects the measurement accuracy. In order to eliminate this effect, a waveform-acquisition module is proposed that converts a broad-spectrum pulse of 1053 nm to a narrow-spectrum pulse of 1550 nm, without affecting the waveform. In addition, a signal-processing algorithm based on the orthogonal matching pursuit method is implemented to remove the sampling noise from the waveform. In this way, the signal-to-noise ratio of the measurement can be readily improved. Both theoretical and experimental results indicate that the proposed FM-AM modulation detection system is effective and economical. It can measure the FM-AM modulation depth precisely, and therefore shows considerable promise for future applications in high-power lasers.
authors.forename: Canhong
authors.initials: C
authors.lastname: Huang
authors.forename: Xinghua
authors.initials: X
authors.lastname: Lu
authors.forename: Youen
authors.initials: Y
authors.lastname: Jiang
authors.forename: Xiaochao
authors.initials: X
authors.lastname: Wang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Qiao
authors.forename: Wei
authors.initials: W
authors.lastname: Fan