Sensitivity enhancement in erbium-doped fiber laser intra-cavity absorption sensor

The sensitivity of an erbium-doped fiber laser intra-cavity loss sensor is investigated theoretically and experimentally. The laser rate equations are modified to analyze the output characteristics of fiber laser under different pump powers and intra-cavity losses. Theoretical analysis shows that high sensitivity can be achieved when pump power is reduced to close to threshold value. The general trends of experimental results agree with the theoretical predictions.