啁啾光纤光栅EDFA增益平坦滤波器的设计与制作

Design and Fabrication of Gain Flattening Filters for EDFA with Chirped Fiber Bragg Gratings

采用啁啾相位掩膜板和程控扫描曝光技术,在经过载氢增敏处理的普通单模光纤上制作出可以用于掺铒光纤放大器(EDFA)增益谱平坦化的啁啾光纤布喇格光栅(CFBG)型增益平坦滤波器(GFF),运用数值解析的方法得到曝光量曲线,并将之分解成曝光频率、曝光功率密度、光斑尺寸和光纤移动速度的曝光函数,按照曝光函数进行程控扫描曝光从而精确控制光栅的反射率。对制作的CFBG进行退火老化处理和温度补偿及保护封装,封装后GFF的温漂系数在-20^+70℃内变化小于1 pm/℃,经平坦后的EDFA增益谱在30 nm带宽范围内,不平坦度<±0.3 dB。根据不同的EDFA的ASE谱,可程控给出不同的曝光函数,以制作具有不同反射谱的CFBG型GFF。

The erbium doped fiber amplifier（EDFA） gain flattening filters were fabricated by writing chirped fiber Bragg gratings on hydrogen loaded standard fiber with chirped phase mask and a properly designed program controlled scanning expose system. The expose dose curve is gotten by numerical analysis and then the expose function is edited with expose frequecy,expose power density,fiber moving speed to preciously eontrl the reflectivity of gratings, the grating is annealed and packaged by using negative temperature coefficient material,and the grating temperature excursion coefficient is lower than 1 pm/℃. The gain variation in an EDFA is within ±0.3 dB over bandwidth of 30 nm. The gain flattening filter based on chirped fiber Bragg gratings can be designed and fabricated according to the different ASE spectrum of EDFA.