16  Gbps random bit generation using chaos in near-symmetric erbium-doped fiber ring laser

We demonstrate a bias-free random bit generator at 16 Gbps using chaos in a near-symmetric erbium-doped fiber (EDF) ring laser. The laser consists of two EDFs, each pumped at 980 nm, two intracavity filters of central wavelength 1549.30 nm, and two 90:10 output couplers. The presence of chaos at the laser output is demonstrated by computing the largest Lyapunov exponent for different embedding dimensions. The laser outputs are photodetected and subtracted to generate an electrical difference signal, which is then sampled at 2 GSa/s and postprocessed to extract random bits at 16 Gbps. The random bits exhibit very low autocorrelation (∼10^-4) and have successfully passed all National Institute of Standards and Technology statistical tests and Diehard battery of tests.