双芯光纤马赫-曾德尔干涉仪的温度特性

对适用于温度传感的双芯光纤马赫-曾德尔干涉仪进行了研究,并通过将一根单模双芯光纤熔接在两根单模光纤之间,制得了双芯光纤马赫-曾德尔干涉仪型梳状滤波器.用干涉原理分别分析了该器件传输谱的自由空间谱宽与波长、双芯光纤的长度和两纤芯间的有效折射率差的关系,实验检测了它的温度特性.结果显示,随着温度的升高,该器件的传输谱发生红...

Temperature characteristic of in-fiber Mach-Zehnder interferometer using twin-core fiber

A Mach-Zehnder interferometer using a Twin-core Fiber(TCF) was researched for temperature sensing and a comb-filter based on the in-fiber Mach-Zehnder Interferometer (MZI) was fabricated by splicing a section of single mode TCF between two single mode fibers (SMFs). The Free Spectral Range(FSR) of the transmission spectrum for the device versa the wavelength, the length of TCF and the effective index difference between the two cores were analyzed and the temperature characteristic of the device was experimentally tested.The tested results indicate that the transmission spectrum of the device has a red shift and a quadratic curve with the temperature increasing. Under the same temperature difference, the wavelength shifts are different at different wavelengths and the wavelength shift at short wavelength is smaller than that at longer wavelength. The sensitivity of the device is different at different wavelengths, and it is proportional to the temperature at a fixed wavelength. Furthermore,the insertion loss of the device is decreased effectively by tapering the splicing regions between SMFs and TCF.Finally a device with insertion loss about 7 dB was implemented. This device is relatively small, simple, compatible and suitable for fiber optic temperature sensors.