High power flatness and wide spectrum range microwave frequency combs generation based on an actively mode-locked optoelectronic oscillator with intensity feed-forward path

An actively mode-locked optoelectronic oscillator (OEO) with intensity feed-forward path is proposed and experimentally demonstrated to generate microwave frequency combs (MFCs) with high power flatness and wide spectrum range. An intensity feed-forward path with the same time delay as the delay of the main loop is inserted into an actively mode-locked OEO, which optimizes the power flatness and spectrum range of the generated MFCs signal. Experimental results show that comb lines within +/- 10 dB power variations increase from 15 to 78 and power difference decreases from 8.2 dB to 1.5 dB when the intensity feed-forward path is working in the loop. Moreover, the performance of single sideband (SSB) phase noise with different lengths of SMF inserted in the proposed scheme are also investigated.

Automated summary

An actively mode-locked optoelectronic oscillator (OEO) with intensity feed-forward path is proposed and experimentally demonstrated for generating microwave frequency combs (MFCs) with high power flatness and wide spectrum range. The insertion of an intensity feed-forward path with the same time delay as the delay of the main loop in the actively mode-locked OEO optimizes the power flatness and spectrum range of the generated MFCs signal. Experimental results show significant improvements in power variations and power difference when the intensity feed-forward path is included in the loop. Moreover, the performance of the proposed scheme with different lengths of SMF inserted is also investigated in terms of SSB phase noise.