Transmission edge filters for power equalization of EDFA's

We propose and demonstrate the use of transmission edge filters based on ap odized linearly chirped fiber Bragg gratings for providing power equalizati on among different wavelength channels in an erbium-doped fiber amplifier m odule. The filters we fabricated provide a dynamic range of approximate to 13 dB, an amplitude variation of +/-0.5 dB from an ideal linear edge, and n egligible group delay in transmission. Using the grating filters, we demons trate power equalization, with no observed variation in signal levels after compensation, for three WDM signals having >6-dB difference in power level s before amplification. Our technique can also be extended to provide activ e power equalization by incorporating a feedback loop.