Research On All-Optical Pseudo Random Binary Sequence Generation And Repetition Rate Multiplication

Pseudo-random bit sequences (PRBS) is widely applied to optical transmission systems and optical communication networks for the purpose of error rate measurements, encoding/decoding, encryptions/decryptions, the simulation of white noises, spread spectrum modulations for its good performance of the random characteristics. Though several methods of all-optical PRBS generation have been shown recently, there are a number of problems, such as the complex structure, the short PRBS cycle, the relatively low rate in these solutions. A new all-optical PRBS scheme is proposed, by researching the performance of all-optical devices based on TOAD. This scheme can generate long cycle PRBS without traditional linear shit register (LFSR), so the system structure is greatly simplified. On the other hand, Three schemes of PRBS rate multiplication are proposed, for obtaining a higher rate. This research has crucial for the development of optical communication technology.What I have done during the PHD period are as follows:1、A measuring method of semiconductor optical amplifier (SOA) group velocity dispersion with simple experimental is proposed, and its reliability is verified by an experiment under the condition of small signal inputs. I analyzed the dependence of the additional window on the recovery time of SOA in the TOAD loop. For 2.5Gb/s RZ code, experiments demonstrate that the duty ratio can be compressed from 50%(200ps) to 25%(100ps) and even 10%(40ps), and then be exteneded from 25%to 50%.2、A scheme of all-optical frequency doubling based on TOAD is proposed. I simulated twice and three and four times the frequency increases of the clock signal. I achieved wavelength conversion with a pulse width at 100ps based on TOAD.. And I achieved all-optical AND-logic and OR-logic and XOR-logic based on TOAD experimentally.3、A scheme for all-optical PRBS generator is demonstrated with optical logic gate ’XNOR’ and all-optical wavelength converter based on cascaded TOADs with a simple structure for abandoning LFSR. Its feasibility is verified by generation of return-to-zero on-off keying (RZ-OOK) 2^63-1 PRBS at the speed of 1Gb/s with 10% duty radio. The high randomness of ultra-long cycle PRBS is validated by successfully passing the standard benchmark test (Diehard).4、1 proposed three schemes of all-optical repetition rate multiplication for PRBS with the same type:(1) all-optical repetition rate multiplication of PRBS based on cascaded TOADs, whose feasibility is verified by multiplication experiments from 500Mb/s to 4Gb/s for 2^3-1 PRBS and from 1Gb/s to 4Gb/s for 2^7-1 PRBS; (2) all optical repetition rate multiplication of PRBS by employing power coupler and equalizer, whose feasibility has been verified by experiments, which show a multiplication for PRBS at cycle 2^7-1 from 2.5Gb/s to 10Gb/s; (3) all-optical repetition rate multiplication of RZ PRBS using a duty ratio compressor based on TOAD, whose feasibility has been verified by experiments, which show a multiplication for PRBS at cycle 2^7-1 from 2.5Gb/s to 10Gb/s, with a 2dB power penalty compared to the original PRBS.