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Proceedings Paper

Optically-synchronized encoder and multiplexer scheme for interleaved photonics analog-to-digital conversion
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Paper Abstract

Photonics Analog-to-Digital Converters (ADCs) utilize a train of optical pulses to sample an electrical input waveform applied to an electrooptic modulator or a reverse biased photodiode. In the former, the resulting train of amplitude-modulated optical pulses is detected (converter to electrical) and quantized using a conversional electronics ADC- as at present there are no practical, cost-effective optical quantizers available with performance that rival electronic quantizers. In the latter, the electrical samples are directly quantized by the electronics ADC. In both cases however, the sampling rate is limited by the speed with which the electronics ADC can quantize the electrical samples. One way to increase the sampling rate by a factor N is by using the time-interleaved technique which consists of a parallel array of N electrical ADC converters, which have the same sampling rate but different sampling phase. Each operating at a quantization rate of fs/N where fs is the aggregated sampling rate. In a system with no real-time operation, the N channels digital outputs are stored in memory, and then aggregated (multiplexed) to obtain the digital representation of the analog input waveform. Alternatively, for real-time operation systems the reduction of storing time in the multiplexing process is desired to improve the time response of the ADC. The complete elimination of memories come expenses of concurrent timing and synchronization in the aggregation of the digital signal that became critical for a good digital representation of the analog signal waveform. In this paper we propose and demonstrate a novel optically synchronized encoder and multiplexer scheme for interleaved photonics ADCs that utilize the N optical signals used to sample different phases of an analog input signal to synchronize the multiplexing of the resulting N digital output channels in a single digital output port. As a proof of concept, four 320 Megasamples/sec 12-bit of resolution digital signals were multiplexed to form an aggregated 1.28 Gigasamples/sec single digital output signal.

Paper Details

Date Published: 27 March 2008
PDF: 7 pages
Proc. SPIE 6975, Enabling Photonics Technologies for Defense, Security, and Aerospace Applications IV, 69750E (27 March 2008); doi: 10.1117/12.781672
Show Author Affiliations
Carlos Villa, Univ. of Connecticut (United States)
Patrick Kumavor, Univ. of Connecticut (United States)
Eric Donkor, Univ. of Connecticut (United States)


Published in SPIE Proceedings Vol. 6975:
Enabling Photonics Technologies for Defense, Security, and Aerospace Applications IV
Michael J. Hayduk; Peter J. Delfyett; Andrew R. Pirich; Eric J. Donkor, Editor(s)

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