The Fibre Bragg Grating (PMFBG/SMFBG) for 980nm pump laser is written by UV light within the PM980 polarization maintaining fibre (PMF) or SM980 single mode fibre (SMF) core. The PMFBG/SMFBG as pigtail is connected to the 980nm pump laser diode, providing external cavity feedback, which make the pump laser wavelength locked at the center wavelength of PMFBG/SMFBG. Due to the low temperature sensitivity of FBG, the stability of 980nm pump laser wavelength can be greatly improved, and the temperature control of 980nm pump laser is unnecessary. As the PMFBG/SMFBG narrows the bandwidth of the 980nm pump laser output, the ratio of the output power within the erbium ion absorption band can be increased , thereby increasing the efficiency and the stability of the EDFA pump.
FBG for 980nm pump laser is used to lock output wavelength. Due to the low temperature sensitivity of FBG, the stability of output wavelength and the efficiency of 980nm pump laser can be greatly improved.
High–precision control of the reflective wavelength, within ±0.25nm
High-precision control of the reflectivity, within ± 0.5%
Side lobe suppression ratio up to -25dB to -30dB by apodization, better than the industry standard