Compact and low-latency scheme for optical steganography using chirped fibre Bragg gratings

A compact and low-latency approach for optical steganography has been experimentally demonstrated using a matched pair of chirped fibre Bragg gratings. A stealth WDM channel is temporally and spectrally hidden underneath a public optical code division multiple access signal. With the use of chirped fibre Bragg gratings, the length of the pulse compressor/decompressor is reduced by a factor of 2000. The power penalty on the public channel is <1 dB when the stealth signal has a power of 10 dB lower than the public channel.