80 similar to 200GHz erbium doped fibre laser using a rational harmonic mode-locking technique

Pulse trains with repetition rates as high as 80 similar to 200GHz were obtained at 1.55 mu m, using rational harmonic mode-locking with an erbium doped fiber laser. A fundamental repetition frequency (f(osc)) of 40GHz was first generated by applying a 40GHz modulation frequency to an LN intensity modulator in the fibre cavity, in which the longitudinal mode spacing (Delta f) was 1.5MHz. By rationally detuning the modulation frequency by Delta f/n, the authors succeeded in obtaining a repetitive oscillation of (nf(osc)+Delta f). The maximum frequency was 200 GHz, at which n corresponds to 5.