Simplified optical correlation-domain reflectometry using polymer fiber

Abstract

We develop a simplified configuration of optical correlation-(or coherence-) domain reflectometry (OCDR) using a polymer optical fiber (POF). The conventional reference light path is removed by using as reference light the Fresnel-reflected light caused at the interface between a silica single-mode fiber and the POF. We demonstrate its basic operation and investigate the dependences of the spatial resolution and signal-to-noise ratio (SNR) on the sweep time of the laser modulation frequency. The optimal sweep time is found to be 30 ms (corresponding to a repetition rate of 33 Hz), at which both the resolution and SNR are maintained at high values.

Compensation of noise floor distortion in long-range simplified optical correlation-domain reflectometry without the use of electrical spectrum analyzer

“…Optical correlation-domain reflectometry (OCDR), compared to the above two, is a younger technique developed on the basis of the synthesis of optical coherence functions (SOCF), 12) which can perform real-time distributed reflectivity measurement by observing the Fresnel reflection signal returned from the reflective surfaces at relatively low cost and has a unique advantage of random accessibility. [12][13][14][15][16][17][18][19][20][21][22][23] In a standard OCDR configuration, to suppress the low-frequency noise disturbance in the optical heterodyne detection, the frequency of the light reflected from the FUT (or the reference light) is shifted by tens of megahertz using an acousto-optic modulator (AOM). 17) To date, several approaches have been developed to simplify the standard OCDR for the reduction in implementation cost.…”

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.…”

Super-simplified optical correlation-domain reflectometry

“…18) Random accessibility has been achieved by another configuration termed as optical correlation-domain reflectometry (OCDR), which operates on the basis of synthesized optical coherence functions (SOCF). [18][19][20][21][22][23][24][25][26][27][28][29][30] SOCF-OCDR has relatively high spatial resolution, and again, it can selectively measure arbitrary points or areas in an FUT at high speed. Its recent applications include light detection and ranging (LiDAR).…”

“…To date, the experimental setup of SOCF-OCDR has been simplified to reduce its size and cost by removing the AOM; 26) a trial to remove the reference path has also been performed. 28,29) In addition to the AOM and the reference path, if all the EDFAs can be removed from the setup, the system will be supersimplified.…”