Optical Label Switching Technology Based On Pattern Multiplexing

Optical label switching(OLS:optical label switch)is a promising solution for rapidly growing packet based internet traffic and data switching in data center.Most proposed schemes apply orthogonal modulation,which superimpose a non-amplitude modulated label signal onto a Manchester coded or pulse position modulated intensity shift keying(ASK)payload signal.The extinction ratio(ER)has to be reduced for overlaid signal,which reduces the quality of the ASK signal.To avoid the quality degradation of payload signal from low ER,a differential phase shift keying(DPSK)over inverse PPM is proposed in this paper.Due to the high mark ratio of the inverse PPM,the proposed DPSK over inverse PPM modulation achieves a high ER for the ASK signal while induces limited crosstalk to the DPSK signal.Compare with the previously proposed schemes,the test results show the proposed DPSK over inverse 4PPM modulation achieves an optimum ER improvement of at least 6 d B to support an extended of at least 10.5 km.After that,we propose a new modulation format to be applied to optical label switching technology,which applies orthogonal codes to label and payload modulation.Orthogonal codes have been applied to passive optical networks.We chose the simplest pair of orthogonal codes,namely Manchester code and NRZ code,and constructed a new modulation format Manchester code + NRZ modulation.The Manchester coded payload signal the NRZ label signal are combined and then modulated onto an optical carrier by only one ASK modulator.The Manchester coded payload signal and the NRZ label signal are recovered by half-bit-delayed differential and a low-speed ASK receiver,respectively.Better than traditional orthogonal modulation,the proposed Manchester code + NRZ modulation requires no non-amplitude modulation and only one ASK modulator,reducing the equipment cost,modulation loss and operation complexity.The coding is simple and decoding is not required.According to theoretical analysis and simulation test,the induced crosstalk decreases with the bit rate ratio.The tested results verify the feasibility of the OLS based on the proposed Manchester code + NRZ modulation.On this basis,the principle of optical label switching technology based on PAM4-Manchester+NRZ signal was extended in this article and introduced,and its feasibility and specific principles were analyzed.Finally,this paper proposes a new RZ-Manchester signal + Pulse-NRZ orthogonal modulation optical label switching technology,and the coding principle and generation process of RZ-Manchester and Pulse-NRZ codes are introduced,and how to apply to optical label switching is explained.Among the technologies,the feasibility of the optical label switching scheme based on RZ-Manchester and Pulse-NRZ bit multiplexing has been verified through relevant test simulation analysis and comparison and analysis with other orthogonal coded optical label switching technologies.The operation difficulty of payload decoding is reduced,and the receiving performance of the label signal and the payload signal is increased,and only the ASK modulator is needed,and only the amplitude dimension of the signal is used,which greatly increases the scalability of the signal.