Dual-wavelength mode-locked Er-doped fiber laser in a spectral filter free cavity

We present the experimental investigation of a dual-wavelength passively mode-locked Er-doped fiber laser with strict polarization control. The configuration includes a double-pass amplifier with a Faraday mirror and twisted fiber. We observe that including double-twist fiber cancels circular and linear birefringence and allows obtaining dual-wavelength emission varying the losses in the cavity. In contrast, results including single-twist fiber which only emits single-wavelength due to large circular birefringence.

Automated summary

By using double-twist fiber, dual-wavelength emission can be achieved and both circular and linear birefringence can be cancelled out, while single-twist fiber only allows for single-wavelength emission due to large circular birefringence.