Noise of long-range optical frequency domain reflectometry after optical source phase noise compensation

We show that the noise of long range optical frequency domain reflectometry (OFDR) after compensating for the phase noise of the optical source results from environmental acoustic perturbation rather than the compensation process. If both the auxiliary and measurement interferometers are insulated against acoustic noise, the phase noise compensation scheme works almost ideally even over a 20-km range, with at least eight-fold concatenation. Although the spatial resolution achieved by phase-noise compensated OFDR (PNC-OFDR) is influenced by the environmental acoustic perturbation, a resolution of ~10 cm was achieved over 20 km in a normal laboratory environment by insulating the auxiliary interferometer. This approach can be used for mid to long range network diagnosis with a narrow spatial resolution, which is unachievable with other technologies.