Capacity Limit of the Noiseless, Energy-Efficient Optical PPM Channel

Lesh, James R.

doi:10.1109/tcom.1983.1095843

Cited by 37 publications

(16 citation statements)

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“…It is known from earlier work on single-sender, single-detector optical links [7], [8], [10], that classic -ary PPM represents an energy-efficient transmission format if average energy per symbol (or bit) is the efficiency criterion. However, the required peak power from the lasers must become arbitrarily large as increases.…”

Section: A Multipulse Modulationmentioning

confidence: 99%

“…To extend the analysis above to the case of link fading, we assume the fading is fixed over a symbol duration and simply average the (conditional) symbol error probability (10), with respect to the joint fading distribution of the variates. It is emphasized that this produces the symbol error probability averaged over fades.…”

Section: ) Fading No Background Radiationmentioning

confidence: 99%

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Optical repetition MIMO transmission with multipulse PPM

Wilson

Brandt-Pearce

Cao

et al. 2005

IEEE J. Select. Areas Commun.

206

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Abstract-We study the use of multiple laser transmitters combined with multiple photodetectors for atmospheric, line-of-sight optical communication, and focus upon the use of multiple-pulseposition-modulation as a power-efficient transmission format, with signal repetition across the laser array. Ideal (photon counting) photodetectors are assumed, with and without background radiation. The resulting multiple-input/multiple-output channel has the potential for combating fading effects on turbulent optical channels, for which both log-normal and Rayleigh-fading models are treated. Our focus is upon symbol error probability for uncoded transmission, and on capacity for coded transmission. Full spatial diversity is obtained naturally in this application.Index Terms-Multiple-input/multiple-output (MIMO) systems, optical communications, pulse-position-modulation (PPM).

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Section: A Multipulse Modulationmentioning

confidence: 99%

Section: ) Fading No Background Radiationmentioning

confidence: 99%

Optical repetition MIMO transmission with multipulse PPM

Wilson

Brandt-Pearce

Cao

et al. 2005

IEEE J. Select. Areas Commun.

206

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“…In M -PPM [2,15,26,43,[168][169][170][171], k-bits of information are encoded by the position of an optical pulse within an M -slot symbol, (Fig. 7c).…”

Section: -Ary Pulse-position Modulation (M -Ppm)mentioning

confidence: 99%

“…Photon-counting receiver architectures have been proposed [1,26,43,169,170,393] and realized at Mbit/s [44] and ∼Gbit/s [33,34] data rates with the best demonstrated coded RX sensitivities near 1 photon/bit (PPB), with potential for improvement to multiple-bits/photon sensitivities and greatly simplified processing due to the digital nature of the counting process.…”

Section: Direct Detection-photon Countingmentioning

confidence: 99%

Laser communication transmitter and receiver design

Caplan

2007

J Optic Comm Rep

117

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Free-space laser communication systems have the potential to provide flexible, high-speed connectivity suitable for long-haul intersatellite and deep-space links. For these applications, power-efficient transmitter and receiver designs are essential for cost-effective implementation. State-of-the-art designs can leverage many of the recent advances in optical communication technologies that have led to global wideband fiber-optic networks with multiple Tbit/s capacities. While spectral efficiency has long been a key design parameter in the telecommunications industry, the many THz of excess channel bandwidth in the optical regime can be used to improve receiver sensitivities where photon efficiency is a design driver. Furthermore, the combination of excess bandwidth and average-power-limited optical transmitters has led to a new paradigm in transmitter and receiver design that can extend optimized performance of a single receiver to accommodate multiple data rates. This paper discusses state-of-the-art optical transmitter and receiver designs that are particularly well suited for average-power-limited photon-starved links where channel bandwidth is readily available. For comparison, relatively simple direct-detection systems used in short terrestrial or fiber optic links are discussed, but emphasis is placed on mature high-performance photon-efficient systems and commercially available technologies suitable for operation in space. The fundamental characteristics of optical sources, modulators, amplifiers, detectors, and associated noise sources are reviewed along with some of the unique properties that distinguish laser communication systems and components from their RF counterparts. Also addressed is the interplay between modulation format, transmitter waveform, and receiver design, as well as practical tradeoffs and implementation considerations that arise from using various technologies.

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“…Introduction It is well known that optical communications using M-ary pulse position modulation (M-PPM) can provide improved receiver sensitivity [1][2][3][4] that is suitable for ultra-long-haul free-space applications. These benefits have been established with demonstrated receiver (RX) sensitivities approaching 4 photons/bit (PPB) in preamplified RXs [5] and ~1 PPB in photon-counting RXs [6][7][8].…”

mentioning

confidence: 99%

WDM Mitigation of Nonlinear Impairments in Low-Duty-Cycle M-PPM Free-Space Optical Transmitters

Caplan

2008

OFC/NFOEC 2008 - 2008 Conference on Optical Fiber Communication/National Fiber Optic Engineers Conference

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We evaluate the benefits of using WDM for the dual purpose of increasing data rate and mitigating peak-power nonlinearities in high-power M-PPM optical transmitters used in high-sensitivity applications that incorporate forward error correction. 1Introduction It is well known that optical communications using M-ary pulse position modulation (M-PPM) can provide improved receiver sensitivity [1-4] that is suitable for ultra-long-haul free-space applications. These benefits have been established with demonstrated receiver (RX) sensitivities approaching 4 photons/bit (PPB) in preamplified RXs [5] and ~1 PPB in photon-counting RXs [6][7][8]. The sensitivity benefits continue to increase as the alphabet size (M) increases, and the duty cycle, which varies inversely with M, is reduced [2]. However, practical implementation considerations in the transmitter (TX) such as limited electrical (B E ) bandwidth, modulation extinction ratio (ER), and optical nonlinearities can ultimately limit the range of M for a given data rate (R b ) and thus provide a lower bound on realizable sensitivity [9] for a given average TX power.In order to prevent TX peak power loss, a high ER is required for large M. For ER > M + 15 dB, the reduction in peak power is less than 0.1 dB [5]. Commercially available modulators have demonstrated ER > 50 dB [5,10], which enables M ≤ ~1024-ary PPM with negligible penalty. However, nonlinear effects typically limit M to much lower values. Such effects occur when the peak power exceeds a threshold P th , which is about 250W to 1kW in commercially available EDFAs and YDFAs [9,11,12]. For 10W class TXs, this limits M to < ~128. Fast nonlinearities such as self-phase modulation (SPM), four-wave mixing (FWM), and Stimulated Raman Scattering (SRS) tend to shift usable signal power out of band, an effect that reduces TX efficiency and makes an averagepower-limited amplifier appear peak power limited. Standard steps to increase the nonlinear threshold include using larger core fiber to reduce the power density, minimizing amplifier lengths [13], and distributing amplified signal energy in time to lower the effective peak power through the amplifier. This last approach can be achieved using post-amplified chirped-pulse compression, which is limited by the maximum chirp and compensation that can efficiently be employed. Alternatively, WDM distribution has been suggested as a means of reducing the effective peak power and increasing the data-rate in an electrically bandwidth-limited system [5], as shown in Fig. 1. MasterLaser Power Amp Power Amp Master Laser Master Laser Master Laser Intensity Modulator Intensity Modulator Intensity Modulator Intensity Modulator WDM λ 1 λ 2 λ 3 λ w P in P out Magnitude Time λ 1 Δt Δt/M Magnitude Time λ 4Δt 4Δt/M λ 1 λ 2 λ 3 λ 4 WDM/PPM Fig. 1 (Left) Block diagram for notional WDM master oscillator power amplifier (MOPA) TX. Single-channel (upper-right) and w-channel M-PPM/WDM waveforms for w = 4 and M = 8 (lower-right)illustrating the WDM method of diminishing peak signal power by d...

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Capacity Limit of the Noiseless, Energy-Efficient Optical PPM Channel

Cited by 37 publications

References 1 publication

Optical repetition MIMO transmission with multipulse PPM

Optical repetition MIMO transmission with multipulse PPM

Laser communication transmitter and receiver design

WDM Mitigation of Nonlinear Impairments in Low-Duty-Cycle M-PPM Free-Space Optical Transmitters

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