Speaker: Ms. Smaranika Swain EE13D207
Optical communication systems form the back bone of global communication and internet infrastructure due to its high bandwidth capabilities. Increase in spectral efficiency of such systems is possible with the use of advanced modulation formats along with utilization of wavelength, polarization and space division multiplexing. Digital signal processing (DSP) algorithms and their sequence of operation is critical to mitigate the system and channel impairments. In this talk, we first present the experimental results of wavelength division multiplexed optical communication with (a) QPSK modulation through 23 spans (length of 1840 km) of standard single mode fiber, with a per-channel data rate of up to 100 Gbps and an aggregate data rate of 0.8 Tbps (b) QAM modulation through 5 spans (400 km) with an aggregate rate of 1.6 Tbps. We further present the simulations studies on the transmission performance of mode division multiplexed system using a graded index few mode fiber that utilizes LP01 and the degenerate LP11 modes as a means for tripling the spectral efficiency. The corresponding DSP algorithms to recover the effects of linear mode mixing and the influence of laser phase noise in such systems would be presented. Differential mode group delay is a critical impairment in such systems. We experimentally measure the differential mode group delay between the modes of a commercial graded index few mode fiber through linear (Spatially and spectrally resolved imaging and broad band spectrum analysis ) and nonlinear (inter-modal four wave mixing) to be +0.06 ps/m. We conclude by presenting the design of a time division multiplexed (TDM)-SDM receiver architecture that recovers data from all the modes, phase and polarizations coherently with minimal hardware requirement.
All are cordially invited