Frequency-Comb Regeneration for Self-Homodyne Superchannels

We propose and demonstrate frequency-comb regeneration using injection locking and a parametric mixer. We theoretically evaluate the effect of the dispersive walk-off between the two unmodulated carriers from which the comb is regenerated. We calculate the maximum number of carriers which can be regenerated as a function of the laser linewidth and transmission distance when considering dispersion-unmanaged links. Experimentally, we demonstrate a 70 line comb generation without major linewidth degradation from two carriers with 15 dB optical signal-to-noise ratio (OSNR). The low OSNR operation is achieved by the use of optical injection locking. We also evaluate the degradation in the comb regeneration when the carriers are temporally decorrelated in order to emulate the effect of dispersive walk-off. When the temporal delay is 1.5 ns, the comb regeneration does not suffer from major degradation but when the delay is 10 ns, only 30 carriers can be regenerated without linewidth degradation, which agrees with our theoretical analysis.