Speaker – Aneesh S (EE15D011)
Guide: Dr. Deepa Venkitesh
With the advent of advanced modulation formats such as polarization-multiplexed QPSKand 16QAM, the receivers completely rely on digital signal processing for compensation of several impairments that include those originating at the source, coherent receiver and inthe channel. Dispersion compensation is one of the most computationally expensiveprocess among them. In addition, advanced modulation formats require a larger opticalsignal to noise ratio for the same transmission distance, as compared to OOK, and hencethe bit-rate distance product is still limited due to nonlinear effects in fiber. In this context, optical phase conjugation (OPC) is attracting renewed interest because of its ability tocompensate dispersion and nonlinear effects simultaneously. In the present scenario,most of the transmission links have started to exploit polarization diversity schemes toincrease the spectral efficiency. Thus polarization-insensitive phase conjugation with largeconversion efficiency is necessary for countering both CD and non-linearity effects.
In this talk, we will explain the generation of phase conjugate at thefront and back facets of semiconductor optical amplifiers (SOAs) based on the Bragg-scattering from the propagating gratings in the SOAs. We will present a counter-propagating cross-polarized degenerate pumping scheme for polarization-insensitiveconjugate generation, simultaneously in both input and output ports of the SOA. Thecorresponding Bragg scattering processes along with the phase matching conditions willbe described and the experimental validation of the detuning performance of thegenerated conjugate in either port also will be presented. We will further talk aboutdemonstration of polarization-insensitive phase conjugate generation of CW signal at bothinput and output ports of the SOA through Bragg scattering FWM. Experimental results onpolarization-insensitive conjugate generation for 10 GBaud NRZ PM-QPSK (40 Gbps)signal, 10 GBaud NRZ PM-16-QAM (80 Gbps) signal, and 20 GBaud PM QPSK with RCpulse shaping, simultaneously in both input and output ports of SOA will also be presentedin the seminar.
All are cordially invited.