Real-time digital signal processing for coherent optical systems

Abstract

Digital signal processing (DSP) is nowadays a key enabling technology in coherent optical transmission systems, triggering an increasing research effort on the development and optimization of DSP subsystems. The first DSP development step is often based on the use of simulation tools and offline processing of experimental data. Complementarily, real-time implementation is a critical implementation step to assess the performance and feasibility of advanced DSP subsystems. In this work, we address both the offline and real-time stages of development, supported by an experimental optical testbed. Real-time demonstration is enabled by an FPGA processing platform and 1.25 Gsample/s analog-to-digital conversion.

High common mode rejection ratio InP 90° optical hybrid in ultra-broadband at 60 nm with deep-rigded waveguide based on × 4 MMI coupler*

“…Owing to the quadrature phase shift keying (QPSK) modulation technique, the real-time coherent optical transmission systems greatly reduce the transmission loss per bit, thereby improving the data transmission efficiency. [1][2][3][4][5][6][7][8][9][10] Besides, the coherent transmission system offers the more choices of the data transmission rates which are selected by software. [11][12][13][14] Therefore, the real-time coherent optical communication technology has been universally recognized as a preferable choice to improve the transmission speed up to 400 Gb/s and more in the industry.…”