We developed a family of silica-based BDFAs operating over telecom O-band (1260-1360 nm). We demonstrated that 80 meters long single pump single stage amplifier can provide up to 19 dB gain, 20 dBm output power with 5 dB noise figure and 20% power conversion efficiency over 80 nm bandwidth (6-dB). The amplifier gain peak can be flexibly centered over 1305-1325 nm by pump wavelength selection. We designed simple BDFA operating over IEEE standardized part of the O-band (1272-1310 nm) and demonstrated that it can extend 425 Gb/s 400GBASE-LR8 transmission (eight 26.6 Gbaud/s PAM-4 channels) beyond 50 km of G.652 fiber.
This study presents a high-temperature distributed acoustic sensor (HT-DAS) optical fiber that utilizes a single layer of unique specialty coating with elevated thermal stability applied atop a 125 μm single-mode transmission fiber, where the fiber features enhanced Rayleigh backscattering sensitivity combined with long-term robustness and survivability up to 150 °. The developed HT-DAS fiber possesses a similar level of mechanical strength and transmission loss as most industrial specialty and telecommunication optical fibers, but also exhibits remarkable distributed sensing characteristics: enhanced elastic backscattering signal intensity about 12 dB above the base Rayleigh scattering level of non-enhanced fiber. Most importantly, this fiber extends service feasibility to a relatively high temperature regime for 1 year at about 150°C, according to life-time estimation based on thermogravimetric analysis, failure mode analysis, and accelerated aging reliability test.
We demonstrate a 1km long optical fiber with continuous grating enhanced back scattering and attenuation close to standard single mode fiber. Scattering was observed to be more than 10dB above the Rayleigh back scattering of the optical fiber over a 10nm bandwidth between 1542 and 1552nm. The fiber attenuation was estimated to be 0.4dB/km. Our result was enabled through the fabrication of a standard single mode fiber with a UV transparent coating and reel to reel continuous UV grating inscription over more than 1km. We anticipate that enhanced scattering fiber will have impact in many sensor systems that rely on optical back scatter, including distributed acoustic sensing, security applications and structural health monitoring.
We describe the fabrication and performance of a continuously grated twisted multicore fiber sensor array. The grated fiber sensor comprises nearly continuous Bragg gratings along its entire length. The gratings are inscribed over lengths in excess of 10m in fibers with UV transparent coating using a flexible and scalable reel to reel processing system. The arrays are tested using optical frequency domain reflectometry (OFDR). We report on automated analysis routines applied to these OFDR measurements that allow for characterization of 100s of individual grating exposures that make up a continuously grated fiber length. We also report on the spectral loss of the continuously grated fiber, showing that it is suitable for applications with sensors in excess of 100m. Finally, we report on the fiber sensing characteristics by performing measurements of fiber bend using a fiber shape reconstruction algorithm on OFDR traces obtained from four of the fiber cores.