DSP-Enhanced Analog-to-Digital Conversion for High-Speed Data Centers' Optical Connectivities

• Published in: IEEE photonics journal Vol. 7; no. 4; pp. 1 - 13
• Main Authors: Yoffe, Yaron, Sadot, Dan
• Format: Journal Article
• Language: English
• Published: IEEE 01-08-2015
• Subjects: Bandwidth; bit-error-rate; differential-pulse-code-modulatio; Digital signal processing; Encoding; Fiber-optic communications Analog-to-digital conversion; inter-symbol interference; linear equalization; Modulation; Noise; Optical fiber communication; quantization; Quantization (signal); linear equalization; differential pulse code modulation; bit error rate (BER); inter-symbol interference (ISI); Fiber-optic communications analog-to-digital conversion (ADC); quantization
• ISSN: 1943-0655; 1943-0647
• DOI: 10.1109/JPHOT.2015.2458911

As data centers evolve to sustain the economic scale in network traffic, optical interconnections are adapted to support the vast amount of capacity requirements. Among emerging solutions is the incorporation of digital-signal-processing (DSP) functionalities at the receiver to compensate for the optical fiber and optoelectronic components impairments. The bottleneck in such architecture is often implementing a high-resolution and high-speed analog-to-digital-converter (ADC) device, which usually leads to massive power consumption and high costs. In this paper, we propose novel transmission schemes based on low-resolution ADCs, termed DSP-enhanced analog-to-digital conversion. The proposed methods are based on the mathematical principle of predictive quantization, combined with linear equalization theory. Mathematical analysis and performance bounds associated with common channel impairments are derived. Simulation results demonstrate that the DSP-enhanced ADC provides a significant signal-to-noise-ratio (SNR) gain and, subsequently, may enable heavy digital compensation with reduced-resolution ADCs.