AC and DC Gain Tilt of Erbium-Doped Fiber Amplifiers

AC gain tilt and DC gain tilt are defined as the variable gain of an erbium-doped fiber amplifier (EDFA) with input laser wavelength chirp due to modulation, and with different static laser unmodulated wavelengths of no modulation, respectively [1]. This paper proposes a novel experimental setup for measuring AC gain tilt. This paper also clarifies experimentally and theoretically the dependency of the AC gain tilt on the input light modulation frequency from near DC to high frequency. The measured AC gain tilt values at high frequency resemble the measured spontaneous gain tilt values for input wavelengths from 1530 to 1580 nm. The influence of the AC gain tilt effect on AM-SCM video transmission systems is evaluated.