P.R. Prucnal

Princeton University, Princeton, New Jersey, United States

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Publications (458)516.88 Total impact

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    ABSTRACT: We consider an optical technique for performing tunable weighted addition using wavelength-division multiplexed (WDM) inputs, the enabling function of a recently proposed photonic spike processing architecture [J. Lightwave Technol., 32 (2014)]. WDM weighted addition provides important advantages to performance, integrability, and networking capability that were not possible in any past approaches to optical neurocomputing. In this letter, we report a WDM weighted addition prototype used to find the first principal component of a 1Gbps, 8-channel signal. Wideband, multivariate techniques have immediate relevance to modern radio systems, and photonic spike processing networks enabled by WDM could open new domains of information processing that bring unprecedented bandwidth and intelligence to problems in radio communications, ultrafast control, and scientific computing.
    Optics Express 05/2015; 23(10):12758. DOI:10.1364/OE.23.012758 · 3.53 Impact Factor
  • Matthew P Chang, Chia-Lo Lee, Ben Wu, Paul R. Prucnal
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    ABSTRACT: We experimentally demonstrate an optical system that uses a semiconductor optical amplifier (SOA) to perform adaptive, analog self-interference cancellation for radio-frequency signals. The system subtracts a known interference signal from a corrupted received signal to recover a weak signal of interest. The SOA uses a combination of slow and fast light and cross-gain modulation to perform precise amplitude and phase matching to cancel the interference. The system achieves 38 dB of cancellation across 60-MHz instantaneous bandwidth and 56 dB of narrowband cancellation, limited by noise. The Nelder-Mead simplex algorithm is used to adaptively minimize the interference power through the control of the semiconductor’s bias current and input optical power.
    IEEE Photonics Technology Letters 05/2015; 27(9):1-1. DOI:10.1109/LPT.2015.2405498 · 2.18 Impact Factor
  • Matthew P. Chang, Noelle Wang, Ben Wu, Paul R. Prucnal
    Journal of Lightwave Technology 05/2015; 33(10):1-1. DOI:10.1109/JLT.2015.2400399 · 2.86 Impact Factor
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    ABSTRACT: We demonstrate for the first time, to the best of our knowledge, that a Sagnac interferometer can threshold the energies of pulses. Pulses below a given threshold T are suppressed, while those above this threshold are normalized. The device contains an in-loop tunable isolator and 10.4 m of a highly doped silica fiber. We derive an analytical model of the nonlinear optical loop mirror’s pulse energy transfer function and show that its energy transfer function approximates a step function for very high phase shifts (>π). We reveal some limitations of this approach, showing that a step-function transfer function necessarily results in pulse distortion in fast, nonresonant all-optical devices.
    Applied Optics 04/2015; 54(11). DOI:10.1364/AO.54.003218 · 1.78 Impact Factor
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    ABSTRACT: Wireless communications, for data services in particular, have witnessed an exponential growth, and wireless spectrum shortages necessitate increasingly sophisticated methods to use spectrum efficiently. The backhaul of nearly all wireless data networks is fiber-optic. Analog optical signal processing techniques, or microwave photonics, provides an ideal platform for processing wireless information before it is transported to data aggregation centers by fibers. It is in this context that we present recent advances in optical signal processing techniques for wireless radio frequency (RF) signals. Specifically, this chapter is devoted to the discussion of photonic architectures for wideband analog signal processing, including RF beamforming, co-channel interference cancellation, and physical layer security. Photonics offers the advantages not only of broadband operation, but reduced size, weight, and power, in addition to low transmission loss, rapid re-configurability, and immunity to electromagnetic interference. 15.1 Introduction The use of wireless communication is growing exponentially. In June 2012, more than 5.6 billion subscribers had access to and were using a wireless device, nearly 80 % of the total world population of 7.02 billion [1]. By the end of 2017, more than 90 % of the world's population is expected to have access to mobile broadband 3G devices. This statistic demonstrates the importance of mobile wireless comB .J. Shastri and J. Chang—equal contribution.
    All-Optical Signal Processing Data Communication and Storage Applications, Edited by Stefan Wabnitz, Benjamin J. Eggleton, 01/2015: chapter 15: pages 469-503; Springer International Publishing., ISBN: 978-3-319-14991-2
  • IEEE Journal of Selected Topics in Signal Processing 01/2015; DOI:10.1109/JSTSP.2015.2424690 · 3.63 Impact Factor
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    ABSTRACT: We propose an on-chip optical architecture to support massive parallel communication among high-performance spiking laser neurons. Designs for a network protocol, computational element, and waveguide medium are described, and novel methods are considered in relation to prior research in optical on-chip networking, neural networking, and computing. Broadcast-and-weight is a new approach for combining neuromorphic processing and optoelectronic physics, a pairing that is found to yield a variety of advantageous features. We discuss properties and design considerations for architectures for scalable wavelength reuse and biologically relevant organizational capabilities, in addition to aspects of practical feasibility. Given recent developments commercial photonic systems integration and neuromorphic computing, we suggest that a novel approach to photonic spike processing represents a promising opportunity in unconventional computing.
    Journal of Lightwave Technology 11/2014; 32(21). DOI:10.1109/JLT.2014.2345652 · 2.86 Impact Factor
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    ABSTRACT: We propose and experimentally demonstrate a wavelength-division multiplexed (WDM) optical stealth transmission system carried by amplified spontaneous emission (ASE) noise. The stealth signal is hidden in both time and frequency domains by using ASE noise as the signal carrier. Each WDM channel uses part of the ASE spectrum, which provides more flexibility to apply stealth transmission in a public network and adds another layer of security to the stealth channel. Multi-channel transmission also increases the overall channel capacity, which is the major limitation of the single stealth channel transmission based on ASE noise. The relations between spectral bandwidth and coherence length of ASE carrier have been theoretically analyzed and experimentally investigated.
    Optics Letters 10/2014; 39(20). DOI:10.1364/OL.39.005925 · 3.18 Impact Factor
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    Ben Wu, B.J. Shastri, P.R. Prucnal
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    ABSTRACT: System performance of optical steganography is theoretically analyzed and experimentally demonstrated. The optical stealth channel is carried by amplified spontaneous emission noise, which hides the stealth data in both the time and frequency domain. Meanwhile, because the stealth channel uses noise as the signal carrier, the relation between signal-to-noise ratio (SNR) and carrier power is fundamentally different from the traditional optical channels carried by modulating lasers. To transmit and hide the stealth signal in the existing public network, the degradation principle of SNR of the stealth channel is studied. Such principle can guide the design of the stealth transmission system and optimize the carrier power of the stealth channel.
    IEEE Photonics Technology Letters 10/2014; 26(19):1920-1923. DOI:10.1109/LPT.2014.2341917 · 2.18 Impact Factor
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    ABSTRACT: We propose and simulate a novel excitable laser employing passively -switching with a graphene saturable absorber for spike processing. Our approach combines the picosecond processing and switching capabilities of both linear and nonlinear optical device technologies to integrate both analog and digital optical processing into a single hardware architecture capable of computation without the need for analog-to-digital conversion. We simulate the laser using the Yamada model-a three-dimensional dynamical system of rate equations-and show behavior that is typical of spiking processing algorithms simulated in small circuits of excitable lasers.
    Optical and Quantum Electronics 10/2014; 46(10):1353-1358. DOI:10.1007/s11082-014-9884-4 · 1.08 Impact Factor
  • John Chang, James Meister, P.R. Prucnal
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    ABSTRACT: A novel highly scalable adaptive photonic beamformer is proposed and experimentally verified. A single-mode-to-multimode combiner allows our system to recycle the same set of wavelengths for each antenna in the array. A “blind” search algorithm called the guided accelerated random search (GARS) algorithm is shown. A maximum cancellation of ∼37 dB is achieved within 50 iterations, while the presence of a signal of interest (SOI) is maintained. Cancellation across the 900 MHz and 2.4 GHz bands are shown to prove the broadband nature of the optical beamformer.
    Journal of Lightwave Technology 10/2014; 32(20):3623-3629. DOI:10.1109/JLT.2014.2309691 · 2.86 Impact Factor
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    ABSTRACT: We propose an equivalent circuit model for photonic spike processing laser neurons with an embedded saturable absorber---a simulation model for photonic excitable lasers (SIMPEL). We show that by mapping the laser neuron rate equations into a circuit model, SPICE analysis can be used as an efficient and accurate engine for numerical calculations, capable of generalization to a variety of different laser neuron types found in literature. The development of this model parallels the Hodgkin--Huxley model of neuron biophysics, a circuit framework which brought efficiency, modularity, and generalizability to the study of neural dynamics. We employ the model to study various signal-processing effects such as excitability with excitatory and inhibitory pulses, binary all-or-nothing response, and bistable dynamics.
    Optics Express 09/2014; 23(6). DOI:10.1364/OE.23.008029 · 3.53 Impact Factor
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    ABSTRACT: We combine advances in photonic integrated circuits (PICs) with principles from neuromorphic engineering to create a scalable, robust, and extremely high bandwidth bio-inspired computational system. We describe such a system in a wafer-bonded III-V/silicon platform , integrating the network (through passive silicon-on-insulator technology) and the computational elements (through active III-V laser devices) in a single substrate, and corroborate its underlying principles through preliminary bench-top demonstrations.
    Int. Symp. on Nonlinear Theory and its Appl. (NOLTA); 09/2014
  • Alexander N. Tait, Paul R. Prucnal
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    ABSTRACT: We discuss a novel application of a photonic circuit for integrated high-performance neuromorphic signal processing. Large fan-in is an especially important capability in distributed systems; however, electronic physics impose tradeoffs between bandwidth performance and fan-in degree. A circuit developed in the field of radio frequency (RF) photonics, wavelength(λ)-fan-in does not exhibit a corresponding tradeoff and can circumvent prior challenges to fan-in in optical distributed processing applications.
    2014 IEEE/ACM International Symposium on Nanoscale Architectures (NANOARCH); 07/2014
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    ABSTRACT: An optical encryption method based on analog noise is proposed and experimentally demonstrated. The transmitted data is encrypted with wideband analog noise. Without decrypting the data instantly at the receiver, the data is damaged by the noise and cannot be recovered by post-processing techniques. A matching condition in both phase and amplitude of the noise needs to be satisfied between the transmitter and the receiver to cancel the noise. The precise requirement of the phase and amplitude matching condition provides a large two-dimensional key space, which can be deployed in the encryption and decryption process at the transmitter and receiver.
    Optics Express 06/2014; 22(12):14568-14574. DOI:10.1364/OE.22.014568 · 3.53 Impact Factor
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    ABSTRACT: We propose an optical encryption technique where the data is encrypted with wideband analog noise. Matching both the phase and amplitude of the noise is required, providing a large key space for the encryption process.
    CLEO: Applications and Technology; 06/2014
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    ABSTRACT: We demonstrate a photonic coincidence detection circuit with a graphene excitable laser. This technology is a potential candidate for applications in novel all-optical devices for information processing and computing.
    CLEO: Science and Innovations; 06/2014
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    ABSTRACT: The marriage of two vibrant fields---photonics and neuromorphic processing---is fundamentally enabled by the strong analogies within the underlying physics between the dynamics of biological neurons and lasers, both of which can be understood within the framework of nonlinear dynamical systems theory. Whereas neuromorphic engineering exploits the biophysics of neuronal computation algorithms to provide a wide range of computing and signal processing applications, photonics offer an alternative approach to neuromorphic systems by exploiting the high speed, high bandwidth, and low crosstalk available to photonic interconnects which potentially grants the capacity for complex, ultrafast categorization and decision-making. Here we highlight some recent progress on this exciting field.
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    ABSTRACT: Sillion photonic platform development has revolved around point-to-point links for multi-core computing systems. We examine an opportunity for this technology to extend to unconventional architectures that rely heavily on interconnect performance. Broadcast-and-weight is a new approach for joining neuron-inspired processing and optical interconnect physics.
    2014 IEEE Optical Interconnects Conference (OI); 05/2014
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    ABSTRACT: We present the design and simulation results for a photonic integrated circuit (PIC) that performs in-channel and broadband radio-frequency self-interference cancellation. The PIC removes interference by modeling channel effects and inverting a known interferer prior to combining it with the corrupted signal. We present key simulation results showing that the PIC can cancel extremely wideband interferers by ~20 dB. The PIC performance can be improved by reducing signal attenuation and nonlinearities. We plan to fabricate the PIC on a hybrid silicon-on-insulator III-V evanescent photonic platform.
    2014 23rd Wireless and Optical Communication Conference (WOCC); 05/2014

Publication Stats

5k Citations
516.88 Total Impact Points


  • 1986–2014
    • Princeton University
      • Department of Electrical Engineering
      Princeton, New Jersey, United States
  • 2010
    • University of Strathclyde
      • Department of Electronic and Electrical Engineering (EEE)
      Glasgow, Scotland, United Kingdom
  • 2007
    • McGill University
      • Department of Electrical & Computer Engineering
      Montréal, Quebec, Canada
  • 2001–2007
    • Comenius University in Bratislava
      • • Department of Experimental Physics
      • • Faculty of Mathematics, Physics and Informatics
      Presburg, Bratislavský, Slovakia
  • 1993–2006
    • Hofstra University
      • Department of Engineering
      Hempstead, New York, United States
  • 1996
    • Università degli studi di Parma
      Parma, Emilia-Romagna, Italy
  • 1995
    • NEC Corporation
      Edo, Tōkyō, Japan
  • 1986–1989
    • Columbia University
      New York City, New York, United States