Research Of Fiber Identification Device Based On The Sagnac

Due to the optical fiber communication can not only provide a no electromagnetic interference, good environment without conflict, but also can satisfy people’s demand for high bandwidth, optical fiber communication has been widely used. Now, the optical cable has gradually replaced the cable as the most important transmission mode of modern communication network. Operators set more and more of the cable in Wells, pipelines, aerial complex environments and so on, in addition, due to urban renewal, line repair, relocation room new situation constantly emerging, how to identify and manage these complicated optical cable lines also become difficult.Traditional cable identification method is time-consuming, laborious and cost much, developed a cheap and easy to realize optical identification device is particularly important. The article is based on the study of this purpose, the paper proposes a nondestructive and inexpensive optical cable identification method. First, the paper introduces the necessity of research on the optical cable identification and research status at home and abroad. Then designed adjustable constant current source used to drive the DFB fiber laser components, constant current adjustable range from0to100mA, which fulfill the work scope of laser (about25mA), and effective protection circuit are designed, then we carry on experimental test.The paper focus on the working principle of fiber identification device and the hardware and software design scheme are analyzed in detail. Fiber identification device, on the basis of the principle of optical interference light source the light after3dB coupler is divided into two beams of equal, spread along the optical fiber ring arrange, respectively, and then back to the coupler interference occurs. If physical disturbance happened somewhere in the optical fiber ring, interference pattern will have corresponding changed, we can use the photoelectric detector to detect. In this paper, the sensing optical fiber in optical path change has carried on the strict theoretical derivation, the two beams under the action of external force produced by the phase change, among them, the phase changes caused by the factors are discussed and analyzed respectively.At the hardware circuit part, we have consider the photoelectric conversion, direct isolation, amplification, modulus conversion, cache, etc. At the AD conversion part we chose AD7864as sampling chip, it has4channels. Four analog channels can choose according to the circumstance. The use of various channels can be done with software programming. Because sampling chip’s sampling rate and the ARM development board processing data rate are different, we need to do sampling with data obtained from sampling, we chose CY7C4255. It is programmable. The core of hardware parts, we chose S3C2440microprocessor, the CPU is16/32ARM920tRISC processor. Through to the system design content rich peripherals structure, S3C2440can greatly save the cost of the whole system, without additional peripheral circuit configuration. Finally, after the processed signal by ARM development board, LCD display and the audio video information module audio information, so as to achieve the intended purpose. Of course, to make the development board to achieve a predetermined functions, also need to design the driver, this paper analyzes the driver and developed driver system under the Linux system. Using this method to develop the fiber identification device, It is economic and convenient, what’s more, it has good practicability and application prospect.