Polarization-resolved intensity noise in erbium-ytterbium codoped fiber lasers

The intensity-noise properties and polarization dynamics of a two-polarization Er:Yb codoped fiber laser are investigated and discussed. For a laser without polarization control, the low-frequency relative intensity noise reaches a minimum of approximately −90 dB/Hz. Polarization-sensitive detection reveals that the low-frequency intensity noise is influenced by a strong resonance associated with anticorrelated intensity fluctuations of the orthogonal linearly polarized modes. The frequency of the resonance varies linearly with laser power and leads to an increase in low-frequency noise of more than 45 dB for the polarized output of the laser.