Fast Acquisition Tunable High-Resolution Photon-Counting OTDR

Abstract

A 15 dB dynamic range and 4.6 cm spatial resolution tunable photon-counting optical time-domain reflectometer (PC-OTDR) is presented along with a Field Programmable Gate Array (FPGA)-based detection management system that allows several regions of the fiber to be interrogated by the same optical pulse, increasing the data acquisition rate when compared to previous solutions. The optical pulse generation is implemented by a tunable figure-8 passive mode-locked laser providing pulses with the desired bandwidth and center wavelength for WDM applications in the C-band. The acquisition rate is limited by the afterpulse effect and dead time of the employed gated avalanche single-photon detectors. The devised acquisition system not only allows for centimeter-resolution monitoring of fiber links as long as 12 km in under 20 minutes but is also readily adapted to any other photon-counting strategy for increased acquisition rate. The system provides a 20-fold decrease in acquisition times when compared with state-of-the-art solutions, allowing affordable times in centimeter-resolution long-distance fiber measurements. Index Terms-Optical fiber monitoring; optical time domain reflectometry; single-photon detection.

Otdr Por Contagem De Fótons De Aquisição Rápida

“…Este projeto tem como base o trabalho anteriormente desenvolvido por Calliari [11]. Utilizou-se o sistema referido a fim de otimizá-lo e torná-lo mais robusto.…”

“…Na figura 13, apresenta-se a medida de uma janela do sistema nesta configuração. No entanto, observou-se que a dinâmica ainda não alcançava a obtida no artigo [11]. Portanto, foi desenvolvido um sistema para amplificar os pulsos ópticos produzidos pelo Mode-Locked.…”

“…Em seguida, tirar novas medidas avaliando o pulso do SOA. Não obstante, é essencial que o sistema alcance uma dinâmica de aproximadamente 17 dB [11], ou seja, seu máximo. Por fim, o sistema ótimo será utilizado para medir diferentes enlaces.…”

High-Resolution Otdr With Embedded Precise Fault Analysis

“…One way to improve the data acquisition rate of PC-OTDRs was demonstrated in [12], where a train of gates was used to trigger the SPAD multiple times; the results show spatial resolution of 6 meters and descent achievable dynamic range within minute monitoring periods. A similar scheme was used in [80] to improve the data acquisition rate of a parallel work introduced in [13,81]; the results show spatial resolution of 4.6 cm and 15 dB dynamic range.…”

“…However, what stands out the most is the mode locking offering the best bandwidth-to-pulse width ratio [25]. Indeed, mode-locked lasers can achieve near transform-limited pulse generation by employing both semiconductor and fiber gain media [80,[89][90][91].…”