Polarization dependent gain in erbium doped-fiber amplifiers

Measurement of polarization hole burning is reported for an erbium doped fiber amplifier. This effect produces a dependence of gain, measured with a weak probe, on the polarization of the saturating signal; the maximum gain occurs for probe polarizations orthogonal to the signal. The pump also contributes to the gain dependence on polarization. Reduction of the degree of polarization of both pump and signal below 10% reduces the polarization dependent gain substantially.<>