Narrow linewidth operation of an erbium fiber laser containing a chirped Bragg grating etalon

A numerical model is presented which shows that a control signal suitable for preventing longitudinal mode hops can be derived by sensing changes in the polarization state of the light reflected from an intracavity etalon. This is verified experimentally by including a continuous fiber etalon formed from chirped Bragg reflectors in a unidirectional erbium ring fiber laser. Mode hop free operation is observed with resolution limited linewidths of 170 kHz.