Multiwavelength Raman-fiber-laser-based long-distance remote sensor for simultaneous measurement of strain and temperature

Abstract

We propose a simple and flexible multiwavelength Raman-fiber-laser-based long-distance remote-sensing scheme for simultaneous measurement of strain and temperature by use of fiber Bragg gratings. By combining two uniform fiber Bragg gratings with a tunable chirped fiber grating, we readily achieve simultaneous two-channel sensing probes with a high extinction ratio of more than approximately 50 dB over a 50-km distance. When strain and temperature are applied, lasing wavelength separation and shift occur, respectively, since the two uniform fiber Bragg gratings have identical material composition and different cladding diameters. This allows simultaneous measurement of strain and temperature for long-distance sensing applications of more than 50 km.

Two-Wavelength Lasers Based on Oversized Rib Polymer Waveguide Bragg Reflectors

“…하나의 레이저 소자에서 여러 개의 파장이 출력 가능한 다 파장 레이저(Multi-wavelength laser)는 WDM 통신 시스템 [1,2] , 테라헤르츠 신호 생성 [3][4][5][6] , 광 센서 [7] 등과 같은 여러 응용분야 에 다양하게 적용되고 있다. 다파장 레이저를 구현하기 위한 방법으로 어븀 첨가 광섬유와 브래그 격자를 이용한 방법 [3,8,9] 이 제안되었으나, 인접한 파장간에 나타나는 이득 경쟁 (gain competition)으로 인해 안정적인 레이저를 구현하기가 어려운 단점이 있다.…”

Long distance fiber Bragg grating strain sensor interrogation using high speed Raman-based Fourier domain mode-locked fiber laser with recycled residual Raman pump

“…Since the proposed strain sensing probe based on the FBG is affected by strain and temperature simultaneously, it is important to discriminate two concurrent sensitivities. By implementing the specially designed FBG-based sensing probes in the proposed sensing scheme [19], we can obtain the temperature-insensitive, long distance strain sensor based on the proposed Raman-based FDML laser with the recycled residual Raman pump.…”

Recent advances in fiber-optic DNA biosensors

“…2) Fibers are immune to electromagnet, lower temperature-dependence and low loss over long distance transmission [7,8,9].…”

“…This review will provide the information about the application and potential of fiber-optic DNA biosensors classified into two categories depending on the fiber with or without labels-label-free fiber-optic DNA biosensors and labeled fiber-optic DNA biosensor in recent years. With the development of nanotechnology, fiber-optic DNA biosensors have got great progresses because fiber-optic can be easily miniatured to the nanometer scale size by chemical etching [4] or tube etching [5] and mechanically pulled with CO 2 laser heating setup [6], they are immune to electromagnet [7], disposability [8] and long-distance transmission [9]. Because of these properties, fiber-optic DNA biosensors have increasingly attracted more attention to research and develop the new fiber-optic DNA biosensors that integrated with the "nano-bio-info" technology so that they can be employed for in vivo or within single cell test [10], especially in the intracellular measurement for real-time or on-line medical diagnosis [11,12].…”