光纤布拉格光栅制作中心波长控制技术

Control of Central Wavelength in Fiber Bragg Grating Fabrication

为了解决光纤布拉格光栅制作中波长控制的问题,提高已有方案的精度,提出了一种基于相位掩模法刻写布拉格光栅过程中拉力调节和紫外光补偿的光栅刻写波长两步控制法。在光纤两端悬挂砝码调节其所受拉力,使刻写光栅的中心波长略小于目标波长。使用功率均匀的紫外光对光栅整体进行照射,补偿光栅中心波长到目标波长的差距。该方案控制下,光栅中心波长控制误差在±5pm以内,且对原平台改造小,不会破坏刻栅平台稳定性。实验证明1cm长的切趾布拉格光栅反射率可达到30dB以上。相比已有的应力控制方法,该方法具有控制精度高、平台改动小、系统稳定性好的优点。

In order to solve the problem of wavelength control during the fiber Bragg grating fabrication, and to improve the precision of the existing solutions, a method based on the phase mask, including two steps of tension adjustment in the Bragg grating inscription and uniform ultraviolet irradiation, is proposed. The tension is adjusted by hanging weight at both ends of the fiber to make the grating central wavelength slightly smaller than the desired wavelength, then ultraviolet light is irradiated on the grating uniformly along the fiber to compensate the difference between the grating central wavelength and the desired wavelength. The error of grating wavelength is controlled within ±5 pm, and the change of the grating platform is small, which will not destroy the platform stability. Experiment result shows that the reflectivity of 1 cm long apodised Bragg grating reaches more than 30 dB. This method is simpler, more accurate and reliable compared with the existing methods.