80~200 GHz erbium doped fibre laser using a rationalharmonic mode-locking technique

Abstract

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