Showing papers by "Periklis Petropoulos published in 2015"
TL;DR: Simulations indicate that PIAs could reach data rate x reach products in excess of 14,000 Tb/s × km in realistic wavelength-division multiplexed long-haul networks, and technical challenges remaining to be addressed in order for fiber OPAs to become useful for long- haul communication networks are discussed.
Abstract: The prospects for using fiber optical parametric amplifiers (OPAs) in optical communication systems are reviewed. Phase-insensitive amplifiers (PIAs) and phase-sensitive amplifiers (PSAs) are considered. Low-penalty amplification at/or near 1 Tb/s has been achieved, for both wavelength- and time-division multiplexed formats. High-quality mid-span spectral inversion has been demonstrated at 0.64 Tb/s, avoiding electronic dispersion compensation. All-optical amplitude regeneration of amplitude-modulated signals has been performed, while PSAs have been used to demonstrate phase regeneration of phase-modulated signals. A PSA with 1.1-dB noise figure has been demonstrated, and preliminary wavelength-division multiplexing experiments have been performed with PSAs. 512 Gb/s have been transmitted over 6,000 km by periodic phase conjugation. Simulations indicate that PIAs could reach data rate x reach products in excess of 14,000 Tb/s × km in realistic wavelength-division multiplexed long-haul networks. Technical challenges remaining to be addressed in order for fiber OPAs to become useful for long-haul communication networks are discussed.
107 citations
TL;DR: In this article, a flat-structured intra data center architecture with a circuit-switched SDM and TDM hybrid network enables scalable, large-capacity and low-latency DCN communication.
Abstract: This paper reports all-optical, function programmable, transparent, intra- and inter-data center networking (DCN) using space and time-division multiplexing (SDM/TDM) within data centers and wavelength division multiplexing (WDM) between data centers. A multielement fiber is used for SDM transmission to provide a large quantity of optical links between the top-of-racks (ToRs) and the function programmable cluster switch. Beam-steering large-port-count fiber switches, used as central cluster switches and intercluster switch, provide a single hop optical circuit switching solution, and also enable network function programmability for DCN to support variable traffic patterns and different network functions. A TDM switch as a plug-in function provides intra-cluster communication with variable capacity and low latency. The flat-structured intra data center architecture, with a circuit-switched SDM and TDM hybrid network enables scalable, large-capacity and low-latency DCN communication. In addition, all-optical ToR-to-ToR inter-DCN is realized through metro/core networks. A highly-nonlinear fiber based all-optical SDM-to-WDM converter transfers three SDM signals to three-carrier spectral superchannel signals, which are transmitted to the destination DCN, through the metro/core networks. The all-optical ToR-ToR cross-DCN connections enable the geographically distributed DCNs to appear as one big data center.
56 citations
TL;DR: In this paper, a tellurite optical fiber with a suspended core design, formed on a 220-nm wide filament of glass, was used to produce mid-infrared supercontinuum (SC) spectra.
Abstract: We report the fabrication of a tellurite optical fiber with a suspended core design, formed on a 220-nm-wide filament of glass. The fiber was pumped at two different wavelengths (1500 and 2400 nm) using femtosecond pulses generated from an optical parametric oscillator (OPO) in order to produce mid-infrared supercontinuum (SC). We observed that SC spectra extending to 3 µm were readily generated. To further optimize the design, detailed numerical study was performed, which revealed how the fiber structural characteristics dramatically influence the spectral broadening because of the changes in the dispersion profile and in turn, the interplay of nonlinear effects that give rise to SC generation. We found that an accurate control of the core shape can be employed to contain the generated SC spectra within well-defined spectral regions or to provide a broad extension of the continuum to beyond 4 µm.
47 citations
TL;DR: Broadband supercontinuum generation in a dispersion-engineered silicon-germanium waveguide is demonstrated, and excellent agreement with the experimental results was obtained.
Abstract: We demonstrate broadband supercontinuum generation (SCG) in a dispersion-engineered silicon-germanium waveguide. The 3 cm long waveguide is pumped by femtosecond pulses at 2.4 μm, and the generated supercontinuum extends from 1.45 to 2.79 μm (at the −30 dB point). The broadening is mainly driven by the generation of a dispersive wave in the 1.5–1.8 μm region and soliton fission. The SCG was modeled numerically, and excellent agreement with the experimental results was obtained.
42 citations
TL;DR: In this article, a phase-sensitive optical processor is proposed to generate codirectional and π-phase-shifted phase sensitive amplifiers (PSAs) in a single device.
Abstract: We propose and experimentally demonstrate a phase-sensitive optical processor, capable of generating two codirectional and π-phase-shifted phase-sensitive amplifiers (PSAs) in a single device. Phase-sensitive operation is obtained by polarization mixing a phase-locked signal/idler pair generated in a degenerate dual-pump vector parametric amplifier based on four-wave mixing in a highly nonlinear fiber. We refer to this configuration as a polarization assisted PSA and demonstrate some of the applications that it may find. First, we experimentally demonstrate the regeneration of a binary phase shift keying signal in a system that requires only a very low nonlinear phase shift of 0.35 rad. Second, we decompose a quadrature phase shift keying (QPSK) signal into its in-phase and quadrature components. While application to a QPSK signal is shown in our demonstration, we demonstrate numerically that any complex modulation format signal can be decomposed using this approach. Finally, we use our processor to regenerate QPSK signals in a single nonlinear device.
41 citations
03 Dec 2015
TL;DR: A trial of nonlinear impairment mitigation of 16-QAM WDM signals through mid-link optical phase conjugation in transmission over an installed fibre link avoids the typical loss of half the spectral band during phase-conjugation.
Abstract: We present a trial of nonlinear impairment mitigation of 16-QAM WDM signals through mid-link optical phase conjugation in transmission over an installed fibre link. Signal bandwidth is efficiently reused, avoiding the typical loss of half the spectral band during phase-conjugation.
23 citations
10 May 2015
TL;DR: In this article, a 20mm-long low birefringence SiGe waveguide was used to demonstrate a binary step-like phase response and phase-sensitive extinction ratio in excess of 28dB under CW pump operation.
Abstract: A binary step-like phase response and phase-sensitive extinction ratio in excess of 28dB under CW pump operation was demonstrated in a 20mm-long low birefringence SiGe waveguide, using a polarization-assisted phase sensitive amplifier scheme.
10 citations
TL;DR: In this paper, a phase regeneration technique that allows an M-PSK signal to be phase regenerated by an M/2 PSK (or even M/4 PSK) phase regenerator was proposed.
8 citations
22 Mar 2015
TL;DR: Coherently adding a signal's conjugate and third harmonic at the latter's wavelength enables phase quantisation across a large operating power range.
Abstract: Coherently adding a signal's conjugate and third harmonic at the latter's wavelength enables phase quantisation across a large operating power range. With broadband phase noise, a 5.6dB QPSK receiver sensitivity improvement is achieved with BER= 10−4.
7 citations
TL;DR: A scheme for the conversion of spatially multiplexed channels to a wavelength superchannel is presented and characterized and the viability of deployment at network nodes located at the boundaries between spatial-division-multiplexed and standard single-mode fiber wavelength division multiplexing networks is demonstrated.
Abstract: A scheme for the conversion of spatially multiplexed channels to a wavelength superchannel is presented and characterized. The viability of deployment of this scheme at network nodes located at the boundaries between spatial-division-multiplexed and standard single-mode fiber wavelength division multiplexed networks is demonstrated.
6 citations
03 Dec 2015
TL;DR: In this article, the authors demonstrate simultaneous phase regeneration of six NRZ BPSK signals in a single nonlinear medium using FWM-based phase sensitive amplification and BER measurements confirm OSNR improvement and negligible cross-talk across all the regenerated channels.
Abstract: We demonstrate simultaneous phase regeneration of six NRZ BPSK signals in a single nonlinear medium using FWM-based phase sensitive amplification. BER measurements confirm OSNR improvement and negligible cross-talk across all the regenerated channels, impaired with broadband phase noise.
TL;DR: In this article, the authors report on the transient response of a passively mode-locked erbium fiber ring laser as studied by switching the optical pumping of the doped fiber on and off, and confirm that the laser can maintain its mode-locking state even while the pump is modulated.
03 Dec 2015
TL;DR: In this article, phase and amplitude regeneration of a QPSK signal using only two nonlinear stages is achieved by combining a PSA with a saturated pump-degenerate FWM based amplitude squeezer.
Abstract: All-optical phase and amplitude regeneration of a QPSK signal using only two nonlinear stages is achieved by combining a PSA with a saturated pump-degenerate FWM based amplitude squeezer. EVM, phase noise and magnitude noise are all reduced by 50%.
03 Dec 2015
TL;DR: In this article, a polarization-assisted PSA-based phase regenerator was demonstrated in a passive low-birefringence SiGe waveguide at low CW pump power.
Abstract: We demonstrate a polarization-assisted PSA-based phase regenerator in a passive low-birefringence SiGe waveguide at low CW pump power. A PSER of 28.6-dB enables a six-fold reduction in phase-error and BER improvement of approximately 2-dB in the regenerated signal.
10 May 2015
TL;DR: In this paper, a four-wave mixing based amplitude limiter in highly nonlinear fiber based on the Bessel-like power transfer characteristics and highlight trade-offs for phase preserving capabilities is presented.
Abstract: We carry out a detailed experimental characterization of a four-wave mixing based amplitude limiter in highly nonlinear fiber based on the Bessel-like power transfer characteristics and highlight trade-offs for phase preserving capabilities.
22 Mar 2015
TL;DR: It is demonstrated that polarization insensitive FWM-based wavelength conversion of 40Gb/s DPSK signals in a SiGe waveguide, with 0.42-dB polarization-dependent loss, is demonstrated.
Abstract: We demonstrate polarization insensitive FWM-based wavelength conversion of 40Gb/s DPSK signals in a SiGe waveguide, with 0.42-dB polarization-dependent loss. A 1.5-dB Dower nenaltv was measured at a BER of 10−9.
05 Jul 2015
TL;DR: In this article, Bessel function analysis of an amplitude limiter based on four-wave mixing in a highly nonlinear fiber is used to derive formulae for the transfer function and the output noise statistics.
Abstract: We use Bessel function analysis of an amplitude limiter based on four-wave mixing in a highly nonlinear fibre to derive formulae for the transfer function and the output noise statistics. These are confirmed by a detailed experimental characterization. Phase preserving operation is shown by minimizing the signal-pump ratio.
10 May 2015
TL;DR: In this article, the defect-induced mode coupling in a hollow-core photonic bandgap fiber using time-of-flight (TOF) was analyzed and shown its utility in complementing optical time-domain reflectometry.
Abstract: We analyze defect-induced mode coupling in a hollow-core photonic bandgap fiber using time-of-flight, and show its utility in complementing optical time-domain reflectometry
22 Mar 2015
TL;DR: The first demonstration of broadband supercontinuum generation in silicon-germanium waveguides with broadening extended from 1.455μm to 2.788μm upon propagation of ultra-short femtosecond pulses in a 3-cm-long waveguide.
Abstract: We report the first demonstration of broadband supercontinuum generation in silicon-germanium waveguides. Upon propagation of ultra-short femtosecond pulses in a 3-cm-long waveguide, the broadening extended from 1.455µm to 2.788µm (at the −30-dB point).
07 Aug 2015
TL;DR: In this article, a collection of modal characterization techniques based on time-of-flight for multimode fibers for data transmission is presented, with particular focus on hollow-core photonic bandgap fibers.
Abstract: We present a collection of modal characterization techniques based on time-of-flight, that are applicable to multimode fibers for data transmission, with particular focus on hollow-core photonic bandgap fibers.
01 Jun 2015
TL;DR: In this article, a simple wavelength-converting phase quantising scheme based on an idler-free phase-sensitive amplifier was proposed for phase regeneration in Semiconductor Optical Amplifiers (SOAs).
Abstract: Energy consumption, system complexity and potential for integration are important factors when considering the suitability of all-optical processing, and depend upon both the scheme used and the medium in which it is performed. We have recently proposed a simple, wavelength-converting phase quantising scheme based on an idler-free phase-sensitive amplifier, notable for its flexibility of operating power and relative compactness [1]. We have demonstrated its performance for QPSK regeneration using an operating power of 24 dBm in 300 m of highly nonlinear fibre (HNLF). Despite offering low loss and high net nonlinearity, the size and geometry of the HNLF do not make it suitable for integration in a photonic device. Semiconductor optical amplifiers (SOAs) on the other hand, offer a particularly compact medium for nonlinear signal processing, combining an amplifier and nonlinear medium in one device. BPSK phase regeneration has been demonstrated in SOAs [2]; in this paper we experimentally demonstrate, to our knowledge, the first realisation of QPSK phase regeneration in SOAs, making use of the above idler-free scheme to realise a compact and more easily integrated QPSK regenerator.
02 Jul 2015
TL;DR: In this paper, the authors present recent progress in optical signal processing based on compact waveguides fabricated mainly using silicon germanium alloys and present applications such as supercontinuum generation, wavelength conversion and signal regeneration.
Abstract: This talk presents recent progress in optical signal processing based on compact waveguides fabricated mainly using silicon germanium alloys. Applications include supercontinuum generation, wavelength conversion and signal regeneration.