Two-Dimensional Spatio-Temporal Signal Processing for Dispersion Compensation in Time-Stretched ADC

• Published in: Journal of lightwave technology Vol. 25; no. 6; pp. 1580 - 1587
• Main Authors: Tarighat, A., Gupta, S., Sayed, A.H., Jalali, B.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.06.2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Analog-digital conversion; Analog-digital conversion, digital-analog conversion, pcm coding; Analog-to-digital conversion (ADC); Applied sciences; Bandwidth; Converters; Digital; Digitization; Dispersions; Electronics; Exact sciences and technology; Fiber optics; Frequency response; Information, signal and communications theory; Optical distortion; Optical fibers; Optical filters; Optical signal processing; Radio frequency; Signal and communications theory; Signal processing; Signal processing algorithms; Signal to noise ratio; spatio-temporal digital processing; Telecommunications and information theory; time-stretched converters; Ultra wideband technology; Performance evaluation; Power converter; Input signal; Digital processing; Frequency selector; AD converter; Frequency selection; Signal spectrum; Optical characteristic; Frequency response; Transfer function; spatio-temporal digital processing; AD conversion; Digitizing; Two dimensional model; DA converter; Algorithm; Temporal logic; Ultra wide band; Analog-to-digital conversion (ADC); Simulation; Signal processing; Optical dispersion compensation; optical signal processing; Signal to noise and distortion ratio; time-stretched converters
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2007.896758

Time-stretched analog-to-digital converters (ADCs) have offered revolutionary enhancements in the performance of electronic converters by reducing the signal bandwidth prior to digitization. An inherent limitation of the time-stretched ADC is the frequency-selective response of the optical system that reduces the effective number of bits for ultrawideband signals. This paper proposes a solution based on spatio-temporal digital processing. The digital algorithm exploits the optical phase diversity to create a flat RF frequency response, even when the system's transfer function included deep nulls within the signal spectrum. For a 10times time-stretch factor with a 10-GHz input signal, simulations show that the proposed solution increases the overall achievable signal-to-noise-and-distortion ratio to 52 dB in the presence of linear distortions. The proposed filter can be used to mitigate the dispersion penalty in other fiber optic applications as well.