Tunable Broadband Chaotic Signal Synthesis From a WRC-FPLD Subject to Filtered Feedback

The synthesis of wavelength-tunable broadband chaotic signals is experimentally demonstrated by using a weak-resonant-cavity Fabry–Perot laser diode (WRC-FPLD) subject to filtered feedback. To perform the broadband tunability from 1544 to 1556 nm, a tunable optical filter is used for providing filtered feedback to drive the laser into chaos. With adjusting the central wavelength of the filter, about 20 longitudinal modes of the WRC-FPLD can individually realize the chaotic output within the tunable range of the filter. Moreover, by suitably selecting the feedback power, the chaos signal with a flat power spectrum and broad bandwidth up to ~30.0 GHz can be achieved.