Performance limit of a multi-frequency probe based coherent optical time domain reflectometry caused by nonlinear effects

Abstract

The nonlinear effects that limit the performance of the multi-frequency probe (MFP) based coherent optical time domain reflectometry (C-OTDR) are investigated. Based on theoretical analysis and experimental results, compared with conventional C-OTDR, when the probe pulse has power gradient within the pulse width, self-phase modulation (SPM) and cross-phase modulation (XPM) are strengthened in the new C-OTDR scheme. The generation of four-wave mixing (FWM) is dependent on SPM and XPM, and with modulation frequency of phase modulator higher than 40 MHz, the stimulated Brillouin scattering (SBS) threshold can be enhanced by more than 5 dB, which benefits the maximum dynamic range of the MFP C-OTDR.

Detection performance of trigger-controlled Geiger-mode avalanche photodiodes in weak optical signal detection

“…In impulse noise situations, the signal arrives after a high noise pulse, which can be found using optical timedomain reflectometry [3] and partially obscured target laser ranging [4] . In continuous noise situations, the weak signal is obscured by the continuous strong noise, which can be found in faithful swapping experiments [5] and diffuse reflection laser ranging (DRLR) [6] .…”

“…Johnson et al [7] first proposed the multi-trigger GM-APD to improve the detection performance for partially obscured target detection in laser ranging, in which a GM-APD with a short dead time can be triggered multiple times in one gate as long as the dead time is over. Furthermore, Oh et al [3,8] experimentally verified the effectiveness of the multi-trigger GM-APD for partially obscured target detection, compared with the single-trigger GM-APD. However, their investigations were limited to partially obscured target laser ranging.…”

Non-uniform strain measurement along a fiber Bragg grating using optical frequency domain reflectometry

“…The other beam split by coupler C2 reaches the Mach-Zehnder interferometer composed of C2 and C5, as well as a fiber delay line (FD) for realizing nonlinear correction of the light frequency output from the laser [15] . We assume that the arm with the fiber delay line is L m1 long and referred to as the delay channel, whereas the other arm is L m2 long and referred to as the reference channel.…”