Low-frequency FM-noise-induced lineshape: a theoretical and experimental approach

Advanced signal processing methods for pulsed laser vibrometry

“…The proposed ML estimator can be modified in case the noise characteristics differ from those of our primary model; for instance, if there is laser frequency noise in addition to the speckle noise in m(t), then Q m becomes the element-wise product of Q speckle and Q laser , also given by the autocorrelation function of the laser phase noise, found in [17].…”

“…Finally, we have investigated the modification of the ML estimator for laser phase noise incorporated in the signal model, using the autocorrelation predicted by [17] for a narrow linewidth laser [18]. In that case, we notice that while 6-pulse waveforms still bring general precision improvement over pulse-pairs, ML processing does not provide much smaller velocity error than PPP, except for predominant speckle noise as we have already seen, and moderate decorrelations (optical path difference well below laser coherence length).…”

Optically pumped VECSELs: review of technology and progress

“…The linewidth can also be characterized using self-homodyne and self-heterodyne measurements [269], but these measurements are somewhat impractical for VECSELs due to the long fiber delay lines that are required [270,271]. An alternative approach is to use fiber delay lines that are shorter than the coherence length of the laser, and then determine the linewidth via numerical fitting procedures [271][272][273][274]. However, the accuracy of this approach leaves room for improvement, as also mentioned in [29].…”

Coherent phase modulation detection for self-heterodyne phase noise measurement

“…In coherent optical communications the phase noise of laser sources has been identified as a crucial characteristic that affects the BER performance [5]. This has lead to extensive measurement efforts to determine the phase noise characteristic of lasers for transmitters and local oscillators in these systems [4,[6][7][8].…”