用于光纤光栅解调的波长敏感光纤耦合器

为了拓宽光纤耦合器的使用范围,开发光纤耦合器的新功能,采用熔锥技术制作波长敏感耦合器,该耦合器在分光的同时对波长敏感。通过耦合理论验证实验结果,实验数据与理论值相符合。实验中得到波长灵敏度最大值为17.86%/nm的耦合器。采用拉锥工艺制作波长敏感耦合器工艺简单,耦合比峰值对应波长控制易于实现。该耦合器可用于光纤光栅布拉格波长漂移解调。令待解调光纤光栅布拉格波长与耦合器波长灵敏度最大值对应的波长一致,当波长发生漂移时,耦合器输出耦合比发生变化。自制的波长敏感耦合器实现了对布拉格波长为1566.71 nm光纤光栅波长漂移的解调,波长漂移1.80 nm,耦合比变化20.34%。此种解调方式具有光路简单,易于与光纤匹配的优点,可以应用在大型建筑中光纤光栅的健康监测。

Fiber Coupler Sensitive to Wavelength Used to Demodulate Wavelength Shift of Fiber Bragg Grating

In order to extend the application of the fiber couplers and develop the new function of fiber couplers,by utilizing the fused-taper technology,a fiber coupler sensitive to wavelength is obtained.The couplers can split light beam and simultaneously is sensitive to wavelength.The experimental value agrees with the theoretical value.In experiment,the wavelength sensitivity of the coupler is maximized to be 17.86%/ nm.The coupler sensitive to wavelength is easy to be produced by the fused-taper technology and the peak wavelength of the coupling ratio can be well controlled.The coupler can be used to demodulate wavelength shift of fiber Bragg gratings(FBGs).When the Bragg wavelength of FBG agrees with the maximum sensitivity wavelength,the shift of the Bragg wavelength will influence coupling ratio of the coupler output.FBG with 1566.71 nm Bragg wavelength is demodulated by the self-made coupler.When the shift of wavelength reaches 1.80 nm,the coupling ratio varies about 20.34%. The demodulation system is simple and compatible with fiber device.It can be used in health monitoring for huge buildings.