A novel polarization shift keying label rewriting scheme in 43 Gbit/s all-optical label switching network by synchronous polarization modulation is proposed and experimentally demonstrated. The old label can be changed to a new one by just one single step without a label erasure process, which can simplify the network node structure.

A novel method to generate ultra-wideband (UWB) monocycle pulses based on birefringence time delay in polarisation-maintaining fibre (PMF) is proposed and experimentally demonstrated. Two polarityreverse pulses are generated by polarisation modulation using a single phase modulator. They are delayed in PMF with enough time to generate monocycle pulse.

A novel vestigial-sideband (VSB) payload scheme is proposed for high-speed all-optical label-switching (AOLS) networks. The combination and separation of the VSB payload and the optical label is experimentally demonstrated, and the influences of the power-split ratio, time-delay interference, interferometric noise (IN), and wavelength difference between the payload and the label are analyzed. Simulation and experiment results show that this VSB payload scheme can highly reduce the channel bandwidth and it is easy to realize by using optical filters, so it is a potential technique to be used in optical networks with bit rate of 40 Gb/s.

A novel scheme based on 40Gb/s vestigial sideband modulation for optical payload and label multiplex and separation in all optical label switching (AOLS) networks is firstly proposed and experimentally demonstrated. The payload is combined and separated with wavelength labels by optical filters. The experiment results show that after label separation, the power penalties of payload and label are both very little. The influence of the wavelength difference between label and payload is also discussed. The power penalty of payload can be less than 1dB as long as the wavelength difference is larger than 0.1nm. This scheme highly reduces the channel bandwidth of payload and label and is proposing to be used in future optical Internet.

A novel orthogonal modulation scheme of polarization-shift-keying label over vestigial sideband payload is proposed and experimentally demonstrated over a 43-Gb/s alloptical- label-switching transmission. With this scheme, a high extinction ratio of the label is reached, while a spectral efficiency of 0.8 b/s/Hz is achieved by weakening the imperfection of the high-speed pulse sequence in polarization modulation. Furthermore, this modulation scheme is relatively irrelevant with payload bit rate. The payload and label penalties after 80-km NZDSF fiber transmission and label erasure are 1.5 and 1 dB, respectively. The influence of filter center frequency offset is also investigated. Besides, a label rewriting method is introduced to simplify label processing in intermedia nodes. All these results show that this scheme can be a candidate technique for the next-generation optical network.