Time-delay signature concealed broadband gain-coupled chaotic laser with fiber random grating induced distributed feedback

A broadband chaotic laser with a flat power spectrum extending up to ∼7.53 GHz is achieved by injecting continuous wave laser light into a chaotic diode laser perturbed by fiber random grating induced distributed feedback, which forms a gain-coupled chaotic laser system. More than triple bandwidth enhancement is realized with appropriate frequency detuning between the master and slave lasers. Unlike normal chaotic lasers, the output from such a broadband chaotic laser is free from time-delay signature, which can be potentially applied for practical random number generations and will find useful applications in the fields of information security and computation systems.