Research On Key Techniques Of Optical Packet Switched Networks And Important Subsystem Development

Explosive demand on Internet traffic requires an innovative networking technology. The development of photonic packet switching will become a key in meeting the explosive bandwidth requirements of modern communication networks. Optical packet switching (OPS) technology is emerging as an attractive means to increase the functionality of the network optical layer. Particular advantages of this technology are the transparency of the approach to modulation and coding formats, and the highbandwidth it offers.We summarize the main research works as follows:We analyze the characteristics of SOA based on dividing model. We have analyzedthe different characteristics for short optical pulse amplification in SOA. We also have analyzed the nonlinear effection of SOA.An all-optical non retum-to-zero (NRZ) and return-to-zero (RZ) modulation format converter using single semiconductor optical amplifier (SOA) and an optical band-pass filter (OBPF) is proposed. The format converter consists of single SOA which is act as a nonlinear element to broaden the spectrum of input signal and the OBPF which is used to extract the special spectrum from the broadened spectrum. By adopting the ultra-fast SOA model associated with optical system software, the 10Gb/s NRZ and RZ format conversion is successfully demonstrated with simulation. We also demonstrate the proof of the principle experiment at 10Gb/s by using the test SOA and OBF converter. The converted NRZ is achieved with output extinction ratioof 11.51dB. The BER is 5.5×10^-9 while the power of NRZ is -10dBm and the BER is1.0×10^-9 when the power of RZ is -14dBm. The experimental results are wellcoincidence with simulated results. The proposed scheme is robust and potential for applications in future optical networks.We dicussed the all optical buffer. We propose a hybrid optical buffer structure based on slow light using stimulated Brillouin scattering (SBS). We describe a novel methodology to achieve multi-channel, continuously-tunable and small distorted optical delay line using broadband SBS slow-light. We show that optimizing over the powers and band width of two Gaussian-shaped broad band pumps can decrease the pulse distortion. We demonstrate these concepts by comparing the smallest pulse distortion achievable using two Gaussian-shaped broad band pumps gain line with that achievable using single Gaussian-shaped broad band pumps gain lines. Using multi-frequency pumps can realize multi-channel optical delay line based on SBS slow light. Multi-channel delay line can use in wavelength division multiplexing(WDM) networks.A novel optical packet compression/decompression scheme is proposed allowing for high compression rates. We experimentally demonstrate a novel optical packet compression/decompression scheme. In particular, packets at 10Gb/s were compressed into packets at 40Gb/s. We also experimentally demonstrate that packets at 40Gb/s were decompressed into packet at 10Gb/s. The compression technique allows variable length packets. The decompression technique bases on single semiconductor optical amplifier (SOA) and optical bandpass filters (OBF). The proposed scheme is robust and potential for applications in future optical networks.We experimentally demonstrate that packets at 20Gb/s were decompressed into packet at 10Gb/s based on D-flip-flop in the first time. The decompression scheme is also realized RZ to NRZ format conversion. We also experimentally demonstrate that format conversion from the return-to-zero (RZ) to the non-return-to-zero (NRZ) based on D-flip-flop. We use the 13600DF static D flip-flop (Inphi company) to creat control signal which rise time is 15ps and fall time is 14ps.We demonstrated a 1×2 optical switch using LiNbO3 modulators for optical packet switching. The switch can be used to construct N×N all-optical switches for all-optical packet-switched networks. The all-optical switch has a fast response time and high ON/OFF switching ratio. The behavior of the switching device is investigated with numerical simulations and experimental measurements. We have demonstrated an all-optical packet switching using the LiNbO3 modulator. We experimentally demonstrate the optical packets switch at 40Gb/s and 80Gb/s. Because of the use of LiNbO3 modulators, higher data rates and integration are possible. The switching time of optical packets switching will approach about 29ps. Therefore, the proposed optical switch will be promising to optical packet switch networks. The 1×2 switching cell can form the building block for the construction of 1×N optical routers.In introduction, we introduce the history of optical communications. In conclusion and outlook, we analyse the development uptrend of optical packet switched networks.