Highly parallel pulsed optoelectronic analog-digital converter

Abstract

We characterize the performance of a highly parallel pulsed optoelectronic analog to digital converter. The system is based on a time-domain to wavelength-domain mapping, such that an input analog signal is parallelized using a wavelengthdivision-demultiplexed scheme. Each parallel wavelength channel is then digitized using conventional, slow electronic analog-digital converters. We use narrow-band signals up to 18 GHz and histogram testing to characterize the system. From the measurements, we deduce the effective number of bits of the system to be 6 and 5 bits for 4 and 36 giga-samples-per-second (GSPS) sampling rates, respectively.Index Terms-Analog-digital conversion, optical data processing, wavelgnth-division multiplexing.

Optically sampled analog-to-digital converters

“…Substituting (18) and (19) into (13) gives for detector shot noise (20) Equation (20) reveals that is independent of for the case of shot noise. The reason for this independence is that the total average energy output from the modulator is a constant, i.e., .…”

“…In these architectures, spectrally broad and temporally short optical pulses are either: 1) temporally broadened using a dispersive medium [19], [20] or 2) separated into distinct pulses, each at a different wavelength, with interpulse temporal spacing of , where is the period of the initial pulse train [21]- [24]. Discrete-wavelength pulse separation has been achieved using a wavelength-division multiplexer (WDM) along with fiber delay lines [21], [23] and an arrayed-waveguide grating (AWG) with integrated feedback waveguides [22], [24].…”

Direct sampling of Ka-Band signals using a photoconductive switch approach

“…Several approaches of electro-photonic ADCs have been already proposed including wavelength division multiplexing [2], time division multiplexing [3], parallel optics [4], ultra fast optical modulators, mode-locked lasers for time sampling, time stretch [5,6] or combinations of these.…”

<title>Wavelength-based analog-to-digital conversion</title>

“…Early realizations of photonic ADC's utilized the speed of electrooptic Mach-Zehnder amplitude modulators. Since the ADC represents an essential link between the sensor and signal processor there is again renewed interest in high-speed ADC technology and many novel approaches are currently being investigated [4][5][6][7]. These systems were generally limited in resolution primarily by modulator electrode length, or more specifically the limits imposed by practical values of V, as well as, though to a lesser degree, by RF signal distribution problems.…”