Super-simplified optical correlation-domain reflectometry

Abstract

Optical correlation-domain reflectometry (OCDR), which is known as one of the fiber-optic techniques for distributed reflectivity sensing, conventionally included an acousto-optic modulator, a reference path, and erbium-doped fiber amplifiers in its setup. In this work, by removing all of these components simultaneously, we develop a super-simplified configuration of OCDR, which consists of a light source and a photodetector only. We experimentally show that this system can still perform distributed reflectivity sensing with a moderate signal-to-noise ratio, which will boost the portability and cost efficiency of the OCDR technology.

Simplified correlation-domain LiDAR without long delay fiber

“…[25][26][27][28] However, the initial demonstration of correlation-domain LiDAR suffered from the utilization of a 300 m long delay fiber, making the system bulky and necessitating additional efforts in miniaturization and integration for future practical applications. [29][30][31][32][33] Note that this issue has been mitigated in fiber-optic sensors but not in LiDAR systems.…”

Observation of Rayleigh scattering by simplified optical correlation-domain reflectometry without frequency shifter

“…As an alternative to OTDR and OFDR, optical correlationdomain reflectometry (OCDR) [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] has been developed on the basis of the synthesis of optical coherence functions. 15) OCDR can be implemented at a relatively low cost and has a unique advantage called random accessibility, i.e.…”

“…26) Other types of simplified configurations without the direct use of a reference path have also been reported. [27][28][29] To further simplify the OCDR system, we have recently developed a new configuration that eliminates the need for an electrical spectrum analyzer (ESA), which builds upon the AOM-free OCDR system and boasts enhanced spatial resolution and operational speed. 30) However, these improvements come at a cost of significant noise for long-range measurements, as has been reported previously.…”

“…Note that the measurement range D and the spatial resolution Dz are given in the same manner as those in standard OCDR by Eqs. (2) and (3):33) c is the light velocity in vacuum, n is the refractive index of the fiber core, and f z is the center frequency of the zero-span function of the ESA. The observation of Rayleigh scattered signals has proven to be challenging in AOM-free OCDR due to the tendency of the weak signal to be buried by low-frequency disturbance.…”