The Sensitive Characteristics Of Fused-tapered Single Mode Fiber Coupler

The single-mode optic fiber coupler made by using the technique of fused biconical taper is an essential optical passive element in optical fiber communication, optical sensing and optical testing system, while its usage as optical fiber sensor is rarely reported. Through theoretical analysis and experimental validation, this dissertation researches the response characteristics of fused fiber coupler to the exoteric environment temperature, input light wavelength and the refractive index of exoteric liquid medium etc., which, when calibrated, may be used for sensing corresponding physical elements. The contents of this dissertation are:A. Introducing the coupling mechanism of fused-tapered single mode fiber coupler, which provides the theoretical basis for the research of the characteristics of fused fiber coupler.B. Developing a 3dB coupler, namely the coupling ratio is 50%, with working wavelength of 1550nm, and testing its parameters.C. Researching on the sensitive characteristics of fused fiber coupler to temperature, Deducing theoretical formula and curves by analysis. Packaging fused fiber coupler with enhanced temperature sensitivity, constructing experimental system to validate the theoretical analysis, which proves that, in a certain temperature range, the coupling ratio of fused fiber coupler varies with the outside temperature approximately linearly, while the extra loss strictly linearly.D. Analyzing the response characteristics of the coupling ratio of fused fiber coupler to wavelength of the input light in theory, pointing out that these two elements vary linearly in a certain wavelength range, which is validated in experiments.E. Analyzing the response characteristics of fused fiber coupler to the refractive index of exoteric...