Spectral sub-band synthesis using multiple independent lasers and receiver DSP for high baud-rate single-carrier Tb/s transmissions

Abstract

In recent years, the ever-emerging internet application has driven the development of optical communication capacities. Other than meeting the current demand, the increment of capacity will enable various applications which could be or could not be imagined, including remote diagnosis and remote surgery. To achieve this goal, effort needed to be made on both transmitter and receiver side. On the transmitter side, most of the proposed spectral slicing transmitters in previous journals included a key component named frequency comb generator, which generates a series of carriers with different frequency by a single monochromatic laser. The generated carriers will then be modulated separately and multiplexed at transmitter output. Owing to the characteristics of frequency comb generator, frequency as well as phase of carriers were locked, thus larger bandwidth signal could be generated at ease. We are proposing a different transmitter architecture, which replaced the monochromatic laser and frequency comb generator with multiple sets of monochromatic lasers, aiming to improve the flexibility achieving single carrier transmission. However, given frequencies and phases of lasers were not locked in the proposed setup, new symbol distortion was found in the research progress and was discussed in this thesis. To overcome distortion brought by the proposed transmitter, we also proposed a digital signal processing (DSP) platform, which consists of modified frequency offset estimation algorithm, conventional CMA, and BPS at the receiver. Simulation result showed a transmission rate of 1 Tb/s could be achieved with PM-16-QAM format and 4 lasers.