title: All-fiber dynamic gain equalizer based on a twisted long-period grating written by high-frequency CO2 laser pulses.
abstract: A novel dynamic gain equalizer for flattening Er-doped fiber amplifiers based on a twisted long-period fiber grating (LPFG) induced by high-frequency CO(2) laser pulses is reported for the first time to our knowledge. Experimental results show that its transverse-load sensitivity is up to 0.34 dB/(g.mm(-1)), while the twist ratio of the twisted LPFG is approximately 20 rad/m, which is 7 times higher than that of a torsion-free LPFG. In addition, it is found that the strong orientation dependence of the transverse-load sensitivity of the torsion-free LPFG reported previously has been weakened considerably. Therefore such a dynamic gain equalizer based on the unique transverse-load characteristics of the twisted LPFG provides a much larger adjustable range and makes packaging of the gain equalizer much easier. A demonstration has been carried out to flatten an Er-doped fiber amplifier to +/-0.5 dB over a 32 nm bandwidth.
authors.affiliation: Department of Optoelectronic Engineering, Chongqing University, China.
authors.forename: T
authors.initials: T
authors.lastname: Zhu
authors.forename: Y J
authors.initials: YJ
authors.lastname: Rao
authors.forename: J L
authors.initials: JL
authors.lastname: Wang