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Showing papers on "Wavelength-division multiplexing published in 2007"


Journal ArticleDOI
TL;DR: Several key enabling technologies for hybrid optical-wireless access networks are described, including optical millimeter-wave (mm-wave) generation, upconversion, and transmission in a downlink direction, and full-duplex operation based on wavelength reuse by using a centralized light source in an uplink direction.
Abstract: The integration of optical and wireless systems is considered to be one of the most promising solutions for increasing the existing capacity and mobility as well as decreasing the costs in next-generation optical access networks. In this paper, several key enabling technologies for hybrid optical-wireless access networks are described, including optical millimeter-wave (mm-wave) generation, upconversion, and transmission in a downlink direction, and full-duplex operation based on wavelength reuse by using a centralized light source in an uplink direction. By employing these enabling technologies, we design and experimentally demonstrate an optical-wireless testbed that is simultaneously delivering wired and wireless services in the integrated optical-wireless and wavelength-division-multiplexing passive-optical-network access networks. The actual applications consisting of 270-Mb/s uncompressed standard-definition TV signal and 2.5-Gb/s data channels for downstream are successfully transmitted over a 25-km fiber and a 10.2-m indoor wireless link with less than a 1.5-dB power penalty. The results show that this integrated system is a practical solution to deliver superbroadband information services to both stationary and mobile users.

323 citations


Journal ArticleDOI
01 Jan 2007
TL;DR: In this article, a combination of orthogonal frequency division multiplexing (OFDM) and optical single sideband modulation (OSM) is used to compensate for chromatic dispersion in ultralonghaul wavelength-division multiplexed (WDM) systems.
Abstract: We show, using simulations, that a combination of orthogonal frequency division multiplexing (OFDM) and optical single sideband modulation can be used to compensate for chromatic dispersion in ultralong-haul wavelength-division multiplexed (WDM) systems. OFDM provides a high spectral efficiency, does not require a reverse feedback path for compensation, and has a better sensitivity than nonreturn to zero. This paper provides design rules for 800-4000-km optical-OFDM systems. The effects of WDM channel number and spacing, fiber dispersion, and input power per channel on the received Q are studied using extensive numerical simulations. These effects are summarized as a set of design rules

295 citations


Journal ArticleDOI
TL;DR: In this paper, the authors show that tuning the parameters of an optical cavity induces filtering of different colours of light, which can also change the color of light. And they demonstrate a change in wavelength of up to 2.5 nm with up to 34% on-off conversion efficiency.
Abstract: As the demand for high bandwidths in microelectronic systems increases, optical interconnect architectures are now being considered that involve schemes commonly used in telecommunications, such as wavelength-division multiplexing (WDM) and wavelength conversion1. In such on-chip architectures, the ability to perform wavelength conversion is required. So far wavelength conversion on a silicon chip has only been demonstrated using schemes that are fundamentally all-optical2,3,4,5,6, making their integration on a microelectronic chip challenging. In contrast, we show wavelength conversion obtained by inducing ultrafast electro–optic tuning of a microcavity. It is well known that tuning the parameters of an optical cavity induces filtering of different colours of light7. Here we demonstrate that it can also change the colour of light. This is an effect often observed in other disciplines, for example, in acoustics, where the sound generated by a resonating guitar string can be modified by changing the length of the strings (that is, the resonators)8. Here we show this same tuning effect in optics, enabling compact on-chip electrical wavelength conversion. We demonstrate a change in wavelength of up to 2.5 nm with up to 34% on–off conversion efficiency.

283 citations


Journal ArticleDOI
TL;DR: This work transfers an optical frequency over 251 km of optical fiber with a residual instability of 6x10(-19) at 100 s and gives a simple expression for calculating the achievable instability and jitter over a fiber link.
Abstract: We transfer an optical frequency over 251 km of optical fiber with a residual instability of 6x10(-19) at 100 s This instability and the associated timing jitter are limited fundamentally by the noise on the optical fiber and the link length We give a simple expression for calculating the achievable instability and jitter over a fiber link Transfer of optical stability over this long distance requires a highly coherent optical source, provided here by a cw fiber laser locked to a high finesse optical cavity A sufficient optical carrier signal is delivered to the remote fiber end by incorporating two-way, in-line erbium-doped fiber amplifiers to balance the 62 dB link loss

215 citations


Proceedings ArticleDOI
TL;DR: In this article, the authors proposed and demonstrated a new and efficient approach to generate a CW SC in optical fibers pumped by a CW ASE light, achieving a spectral bandwidth of over 1000nm.
Abstract: In this paper, we studied SC generation in fiber lasers and in optical fibers pumped by different light sources which include fs and ps pulse sources, and continuous-wave (CW) amplified spontaneous emission (ASE) light sources. First, we demonstrated SC generation with a 10dB spectral bandwidth of 430nm in a fiber ring laser with conventional nonlinear fiber. Second, we proposed and demonstrated a new and efficient approach to generation of a CW SC in optical fibers pumped by a CW ASE light. A bandwidth of 268nm (at -15dB level) with an average spectral density of 2.7mW/nm was demonstrated. Various approaches to flattening the spectrum and increasing the spectral width were also studied. The application of this SC source in WDM passive optical access networks (WDM-PONs) was investigated. Third, the approach of SC generation in a fiber combination of standard SMF and nonlinear DSF pumped by an all-fiber fs pulse Master Oscillator Power Amplifier (MOPA) system was developed. A spectral bandwidth of over 1000nm was demonstrated. Finally, the generation of broad comb-like-spectral light based on the pulse compression of 40GHz optical pulses in a new nonlinear dispersion-decreasing fiber with high SBS threshold was studied. A continuum light source with over 125 channels and a channel spacing of 40 GHz was achieved. The use of this continuum light source as WDM source in WDM-PONs was investigated.

180 citations


Journal ArticleDOI
01 Jan 2007
TL;DR: In this article, a self-seeding RSOA was used to achieve a BER of 10-9 with only -30.5 dBm of initial optical seeding power.
Abstract: The deployment rate of wavelength division multiplexed passive optical networks (WDM-PONs) is expected to accelerate with the availability of cost-efficient wavelength-specific transmitters. Fueled by this promise, we propose and experimentally demonstrate a novel scheme that facilitates the use of reflective semiconductor optical amplifiers (RSOAs) as colorless upstream transmitters. Central to the scheme is the use of a passive reflective path that is placed at the remote node (RN) to reflect a spectral slice of the broadband amplified spontaneous emission (ASE) light emitted from each RSOA. The reflected spectral slice, termed as a seeding light, establishes a self-seeding of the RSOA with measurements indicating the self-seeded output to be incoherent with a low relative intensity noise. The subsequent direct modulation of the self-seeding RSOA with nonreturn-to-zero data at 1.25 Gb/s for upstream transmission exhibits good transmission and crosstalk performance after traversing 21 km of single-mode fiber. Our proposed scheme eliminates the need for centralized broadband sources, external modulators, and active temperature control within the RN and between the RN and the optical network unit. Aside from the feasibility study of self-seeding RSOAs, we investigate the upstream performance dependence on the characteristics of the seeding light. Our investigations reveal that there exists a noise floor limit of the bit error rate (BER) of the self-seeded upstream signal. The noise floor is shown to vary with an initial optical seeding power that affects the level of ASE noise suppression of the self-seeded upstream signal. None the less, the RSOA self-seeds at a user-defined wavelength with a sufficient suppression of ASE noise to achieve a BER=10-9 with only -30.5 dBm of initial optical seeding power. Our characterization of the frequency response of the RSOA reveals a high-pass filter response that suppresses the modulation on the reflected seeding light, and thus stabilizing the self-seeded output. Collectively, these features highlight the potential of using the self-seeding RSOAs to realize a cost-efficient WDM-PON solution in the near future

176 citations


Journal ArticleDOI
TL;DR: It is shown that the optical fiber channel model can be treated as a special kind of multiple-input multiple- output (MIMO) model, namely, a two-input two-output (TITO) models which is intrinsically represented by a two -element Jones vector familiar to the optical communications community.
Abstract: In this paper, we conduct theoretical and experimental study on the PMD-supported transmission with coherent optical orthogonal frequency-division multiplexing (CO-OFDM). We first present the model for the optical fiber communication channel in the presence of the polarization effects. It shows that the optical fiber channel model can be treated as a special kind of multiple-input multiple-output (MIMO) model, namely, a two-input two-output (TITO) model which is intrinsically represented by a two-element Jones vector familiar to the optical communications community. The detailed discussions on various coherent optical MIMO-OFDM (CO-MIMO-OFDM) models are presented. Furthermore, we show the first experiment of polarization-diversity detection in CO-OFDM systems. In particular, a CO-OFDM signal at 10.7 Gb/s is successfully recovered after 900 ps differential-group-delay (DGD) and 1000-km transmission through SSMF fiber without optical dispersion compensation. The transmission experiment with higher-order PMD further confirms the immunity of the CO-OFDM signal to PMD in the transmission fiber. The nonlinearity performance of PMD-supported transmission is also reported. For the first time, nonlinear phase noise mitigation based on receiver digital signal processing is experimentally demonstrated for CO-OFDM transmission.

160 citations


Journal ArticleDOI
TL;DR: Electrically pumped lasers on silicon that produce pulses at repetition rates up to 40 GHz could enable new silicon based integrated technologies, such as optical time division multiplexing (OTDM), wavelength division multipleXing (WDM), and optical code division multiple access (OCDMA).
Abstract: We demonstrate electrically pumped lasers on silicon that produce pulses at repetition rates up to 40 GHz. The mode locked lasers generate 4 ps pulses with low jitter and extinction ratios above 18 dB, making them suitable for data and telecommunication transmitters and for clock generation and distribution. Results of both passive and hybrid mode locking are discussed. This type of device could enable new silicon based integrated technologies, such as optical time division multiplexing (OTDM), wavelength division multiplexing (WDM), and optical code division multiple access (OCDMA).

149 citations


Journal ArticleDOI
TL;DR: A 1x2 all-optical comb switch using a 200 mum diameter silicon ring resonator with a switching time of less than 1 ns is demonstrated, which overcomes the small bandwidth of the traditional ring resonators, and works for wavelength division multiplexing applications.
Abstract: We demonstrate a 1×2 all-optical comb switch using a 200 µm diameter silicon ring resonator with a switching time of less than 1 ns. The switch overcomes the small bandwidth of the traditional ring resonator, and works for wavelength division multiplexing applications. The device has a footprint of ~0.04 mm2 and enables switching of a large number (~40) of wavelength channels spaced by ~0.85 nm.

126 citations


Patent
20 Jul 2007
TL;DR: In this article, the authors presented an approach for detecting at least one object and preventing receiver burn-out, mounted on a vehicle, including a laser and one receiver, the receiver being coupled with the laser, the laser for transmitting a beam of light and the receiver for detecting reflections of the beam-of-light from the object, the circulator being optically coupled with each signal diode, the EDF and the output combiner.
Abstract: Apparatus, for detecting at least one object and preventing receiver burn-out, mounted on a vehicle, including a laser and at least one receiver, the receiver being coupled with the laser, the laser for transmitting a beam of light and the receiver for detecting reflections of the beam of light from the object, the laser including at least one signal diode, a commutator, a power supply signal diode driver, a circulator, an erbium doped fiber (EDF), a wavelength division multiplexer (WDM), a narrow band Bragg reflector, a first fiber pump diode, an output combiner and a second fiber pump diode, the commutator being coupled with each signal diode and the power supply signal diode drive, the circulator being optically coupled with each signal diode, the EDF and the output combiner, the WDM being optically coupled with the EDF, the narrow band Bragg reflector and the first fiber pump diode and the second fiber pump diode being optically coupled with the output combiner, each signal diode generating a beam of light distinct from one another, the power supply signal diode driver for supplying energy to each signal diode, the circulator for directing the beam of light in at least one of at least two different directions, the EDF for amplifying the beam of light thereby producing an amplified beam of light, the narrow band Bragg reflector for reflecting only the amplified beam of light through the EDF a second time, thereby producing a double amplified beam of light and the first fiber pump diode and the second fiber pump diode for pumping the EDF, wherein the WDM and each of the signal diodes are located on opposite sides of the EDF, wherein the output combiner outputs the beam of light, wherein the commutator enables each signal diode, one at a time, to draw a predetermined amount of energy from the power supply signal diode driver, wherein one signal diode generates a low energy beam of light and another one generates a high energy beam of light, wherein the low energy beam of light is transmitted by the output combiner before the high energy beam of light, and when the low energy beam of light is detected by the receiver, and the energy level of the low energy beam is above a predetermined threshold, the high energy beam of light is not transmitted.

119 citations


Journal ArticleDOI
TL;DR: A detailed theoretical analysis is presented, showing that using two concatenated modulators driven with voltages of 3.5 V(pi) are necessary to generate 11 comb lines with a flatness below 2dB.
Abstract: A simple and cost-effective technique for generating a flat, square-shaped multi-wavelength optical comb with 42.6 GHz line spacing and over 0.5 THz of total bandwidth is presented. A detailed theoretical analysis is presented, showing that using two concatenated modulators driven with voltages of 3.5 Vp are necessary to generate 11 comb lines with a flatness below 2dB. This performance is experimentally demonstrated using two cascaded Versawave 40 Gbit/s low drive voltage electro-optic polarisation modulators, where an 11 channel optical comb with a flatness of 1.9 dB and a side-mode-suppression ratio (SMSR) of 12.6 dB was obtained.

Journal ArticleDOI
TL;DR: In this article, the authors describe two and three-channel SBC fiber laser systems with 93% power-combining efficiency, near-diffraction-limited beam quality, average output powers in excess of 500 W, and excellent prospects for additional power scaling.
Abstract: Spectrally beam-combined (SBC) laser systems, wherein multiple laser outputs are spectrally multiplexed into a single high-quality beam, are rapidly advancing the power scaling frontier for high-average-power beam-combined fiber lasers with near-perfect beam quality. We describe two- and three-channel SBC fiber lasers featuring 93% power-combining efficiency, near-diffraction-limited beam quality, average output powers in excess of 500 W, and excellent prospects for additional power scaling. To our knowledge, this level of optical performance represents the highest combination of beam quality and average power obtained so far for a beam-combined fiber laser system.

Journal ArticleDOI
TL;DR: A new WDM-PON architecture using Fabry-Pérot laser diodes (FP-LDs) that are injection-locked by continuous wave (CW) seed light that is potentially low from the fact that the CW laser sources located at the central office can be shared by many WDM PONs and low-cost FP- LDs are used as light sources for data rates as high as 10 Gb/s.
Abstract: We propose a new WDM-PON architecture using Fabry-Perot laser diodes (FP-LDs) that are injection-locked by continuous wave (CW) seed light. The modulation characteristics of the CW light injection-locked FP-LD are first investigated. Both uplink and downlink transmissions at 10 Gb/s are experimentally demonstrated using the proposed CW injection-locked FP-LDs. It is shown that up to 16 laser cavity modes can be selectively injection-locked with side mode suppression ratio larger than 30dB. The effects of the location of FP-LD cavity modes, transmission distance, and injection wavelength detuning on the overall transmission performance are investigated. The possibility of eliminating polarization dependence of the proposed CW injection scheme is also experimentally demonstrated by properly configuring a depolarizer. The deployment cost for the proposed WDM PON is potentially low from the fact that the CW laser sources located at the central office can be shared by many WDM-PONs and low-cost FP-LDs are used as light sources for data rates as high as 10 Gb/s.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the benefits of code-division multiple access (CDMA) in optical networks and showed that it offers significant benefits to an optical network and what are the technologies that enable code-based optical networks.
Abstract: Code-division multiple-access (CDMA) has flourished as a successful wireless networking technology in mobile cellular telephony, and wireless local area networks (LAN) such as the unlicensed industry, science, and medicine (ISM) bands. The commercial exploitation of the benefits of CDMA raises the question as to whether optical code-based communications offer significant benefits to an optical network and what are the technologies that enable code-based optical networks. Recent investigations of optical CDMA (OCDMA) strategies have addressed this question through numerous laboratory-based test-bed studies of multiuser link and recent experimental field trials conducted on in-the-ground fiber. OCDMA requires its own physical layer technologies that are distinctly different from widely pursued wavelength-division-multiplexed (WDM) all-optical networks. Simulations of multiuser performance predict ultimate link capacity and the performance of broadcast and select synchronous nets with strong central management as well as asynchronous architectures with reduced centralized management.

Journal ArticleDOI
TL;DR: The results show that the system Q of the WDM channels at 10 Gb/s is over 13.0 dB for a transmission up to 4800 km of standard-single-mode-fiber (SSMF) without dispersion compensation.
Abstract: In this letter, we first present the theoretical basis for coherent optical OFDM systems in direct up/down conversion architecture. We then demonstrate the transmission performance through simulation for WDM systems with coherent optical OFDM (CO-OFDM) including the fiber nonlinearity effect. The results show that the system Q of the WDM channels at 10 Gb/s is over 13.0 dB for a transmission up to 4800 km of standard-single-mode-fiber (SSMF) without dispersion compensation. A novel technique of partial carrier filling (PCF) for improving the nonlinearity performance of the transmission is also presented. The system Q of the WDM channels with a filling factor of 50 % at 10 Gb/s is improved from 15.1 dB to 16.8 dB for a transmission up to 3200 km of SSMF without dispersion compensation.

Proceedings Article
25 Mar 2007
TL;DR: In this paper, a simple direct-detection receiver can post-compensate for dispersion in 320km of SMF28e fiber at 20 Gbit/s.
Abstract: We show experimentally that optical orthogonal frequency division multiplexing using a simple direct-detection receiver can post-compensate for dispersion in 320km of SMF28e fiber at 20 Gbit/s. We also demonstrate a colorless transmitter at 12 Gbit/s.

Journal ArticleDOI
TL;DR: In this paper, a dynamic reconfigurable wavelength-division-multiplexed (WDM) millimeter-waveband (mmWaveband) radio-over-fiber (RoF) access network is proposed.
Abstract: We will propose a dynamic reconfigurable wavelength-division-multiplexed (WDM) millimeter-waveband (mm-waveband) radio-over-fiber (RoF) access network and demonstrate, for the first time, a dynamic-channel-allocation capability of millimeter-waveband optical RoF signals in WDM access network using a supercontinuum light source, arrayed-waveguide gratings, and a reconfigurable optical-crossconnect switch. The dynamic reconfigurable RoF network architecture is presented, and its features are described. Then, four 155-Mb/s RoF channels are effectively generated, transmitted through 25 km of fiber, switched, transmitted again through 2 km of fiber, and detected with an error-free operation (bit error rate < 10-10). The proposed RoF architecture is highly scalable, both in terms of channel and access-point counts.

Proceedings Article
25 Mar 2007
TL;DR: In this article, the measured WDM performance and PMD tolerance of a coherent 40Gbit/s DP-QPSK transceiver at 50GHz minimum channel spacing in a 40-channel, 40-span test bed comprised of 3200 km of uncompensated G.652 fiber are reported.
Abstract: We report the measured WDM performance and PMD tolerance of a coherent 40Gbit/s DP-QPSK transceiver at 50-GHz minimum channel spacing in a 40-channel, 40-span test bed comprised of 3200 km of uncompensated G.652 fiber.

Journal ArticleDOI
TL;DR: In this article, the authors proposed a novel protection scheme compatible with smooth migration from a time division multiplexing (TDM) passive optical network (PON) to a WDM/TDM-PON.
Abstract: We propose what we believe to be a novel protection scheme compatible with smooth migration from a time-division multiplexing (TDM) passive optical network (PON) to a WDM/TDM-PON. We show that our ...

Journal ArticleDOI
TL;DR: In this article, a bidirectional long-reach 64-channel dense wavelength division multiplexing passive optical network (DWDM-PON) based on wavelength-locked Fabry-Peacuterot laser diodes with 50-GHz channel spacing is demonstrated.
Abstract: We demonstrate a bidirectional long-reach 64-channel dense wavelength division multiplexing passive optical network (DWDM-PON) based on wavelength-locked Fabry-Peacuterot laser diodes (F-P LDs) with 50-GHz channel spacing. The mode control of the F-P LDs enhances the output power and decreases the required injection power. Packet-loss-free transmission in both 64 upstream and 64 downstream channels is obtained, guaranteeing more than 100 Mb/s per channel through 70 km of single mode fiber without the need for an optical amplifier. The demonstrated DWDM-PON can consolidate a metro network into an access network by bypassing the central offices within its reach. The capacity of the long-reach DWDM-PON is also discussed

Journal ArticleDOI
TL;DR: In this paper, the effect of group velocity dispersion (GVD) imposes severe limit on information carrying capacity of optical communication systems and the application of solitons in communication systems opens the way to ultrahigh-speed information superhighways.
Abstract: The group velocity dispersion (GVD) imposes severe limit on information carrying capacity of optical communication systems. By choosing appropriate pulse shape highly stable light pulses known as solitons are generated when effect of GVD is balanced by self-phase modulation (SPM). The application of solitons in communication systems opens the way to ultrahigh-speed information superhighways. Transmission speed of order of Tbit/s can be achieved if optical amplifiers are combined with WDM in soliton based communication systems.

Journal ArticleDOI
TL;DR: Experimental results of the FSO system capable of offering stable performance in terms of measured bit-error-rate (BER) showing error free transmission at 2.5 Gbps over extended period of time and improved fiber received power are presented.
Abstract: Free-space optical communication systems can provide high-speed, improved capacity, cost effective and easy to deploy wireless networks. Experimental investigation on the next generation free-space optical (FSO) communication system utilizing seamless connection of free-space and optical fiber links is presented. A compact antenna which utilizes a miniature fine positioning mirror (FPM) for high-speed beam control and steering is described. The effect of atmospheric turbulence on the beam angle-of-arrival (AOA) fluctuations is shown. The FPM is able to mitigate the power fluctuations at the fiber coupling port caused by this beam angle-of-arrival fluctuations. Experimental results of the FSO system capable of offering stable performance in terms of measured bit-error-rate (BER) showing error free transmission at 2.5 Gbps over extended period of time and improved fiber received power are presented. Also presented are performance results showing stable operation when increasing the FSO communication system data rate from 2.5 Gbps to 10 Gbps as well as WDM experiments.

Journal ArticleDOI
05 Nov 2007
TL;DR: An overview is given about application oriented material and device research on this wire/dot-like material system by highlighting laser and high-speed optical amplifiers.
Abstract: InAs quantum-dash structures fabricated by self-assembly growth techniques and based on compound semiconductors lattice matched to InP substrates were used to realize long wavelength lasers and amplifiers for telecom applications. With this new type of laser material special properties of low-dimensional electronic systems can be utilized for device applications, which allow to realize new device features not possible by conventional device designs. In this paper a brief overview is given about application oriented material and device research on this wire/dot-like material system by highlighting laser and high-speed optical amplifiers. Broadband laser material with a gain bandwidth of more than 300 nm could be obtained to cover the extended telecommunication wavelength range between 1.4 and 1.65 . High-speed optical amplifiers could be realized by using this quantum-dash laser material with unique device performance, like multiwavelength amplification without any cross-talk at data rates of 10 Gbit/s and pattern-free and noise reduced signal amplification at saturation condition demonstrated up to 40 Gbit/s.

Patent
07 Mar 2007
TL;DR: In this article, a frequency-agile optical transceiver includes a shared local oscillator (LO), a coherent optical receiver and an optical transmitter, which operates to generate a respective LO optical signal having a predetermined LO wavelength.
Abstract: A frequency-agile optical transceiver includes a shared local oscillator (LO), a coherent optical receiver and an optical transmitter. The LO operates to generate a respective LO optical signal having a predetermined LO wavelength. The coherent optical receiver is operatively coupled to the LO, and uses the LO signal to selectively receive traffic of an arbitrary target channel of an inbound broadband optical signal. The optical transmitter is also operatively coupled to the LO, and uses the LO to generate an outbound optical channel signal having a respective outbound channel wavelength corresponding to the LO wavelength.

Journal ArticleDOI
TL;DR: In this paper, a novel scheme for reducing Rayleigh beat noise in centralized light source dense wavelength-division-multiplexed passive optical networks is demonstrated using an optimized channel-detuned optical filtering of 30 GHz and phase-modulation-induced spectral broadening of a 10-Gb/s upstream nonreturn-to-zero (PM-NRZ) signal.
Abstract: A novel scheme for reducing Rayleigh beat noise in centralized light source dense wavelength-division-multiplexed passive optical networks is demonstrated using an optimized channel-detuned optical filtering of 30 GHz and phase-modulation-induced spectral broadening of a 10-Gb/s upstream nonreturn-to-zero (PM-NRZ) signal. The required optical-signal-to-Rayleigh-noise-ratio (OSRNR), characterized experimentally, can be reduced by up to 16 dB while retaining negligible transmission penalty over 20-km single-mode fiber without dispersion compensation. Numerical analysis is performed to study the tradeoff between OSRNR improvement and attenuation of the PM-NRZ signal as a function of different channel detuning and center wavelength suppressions

Journal ArticleDOI
TL;DR: In this paper, an architecture employing a centralized light source and reflective modulator at the customer is proposed and demonstrated for a long-reach, hybrid DWDM-time-division multiplexed (TDM) passive optical network (PON).
Abstract: Feature Issue on Passive Optical Network Architectures and TechnologiesAn architecture employing a centralized light source and reflective modulator at the customer is proposed and demonstrated for a long-reach, hybrid dense wavelength division multiplexed (DWDM)-time-division multiplexed (TDM) passive optical network (PON). Impairments to the upstream channel caused by Rayleigh backscattering in the network are mitigated using a dual-feeder-fiber approach in conjunction with a novel detuned filtering and spectral-broadening scheme. The experimental results show that the network, with a total reach of 116km and an upstream bit rate of 10Gbits/s, can support up to 256 customers on each TDM PON. The potential performance improvements obtainable from an optimized architecture are also discussed.

Journal ArticleDOI
TL;DR: After characterizing the Raman scattering in a fused silica polarization-maintaining microstructure optical fiber, this work built a fiber-based two-photon light source of high spectral brightness, broad spectral range, and very low noise background at room temperature.
Abstract: After characterizing the Raman scattering in a fused silica polarization-maintaining microstructure optical fiber, we built a fiber-based two-photon light source of high spectral brightness, broad spectral range, and very low noise background at room temperature. The resulting bright low-noise two-photon light can be used for a number of quantum information applications.

Journal ArticleDOI
05 Nov 2007
TL;DR: Modelling of QD polarization dependence shows that it should be possible to achieve polarization insensitive SOAs using vertically coupled QD stacks, and the potential for their application in future 100 Gb Ethernet networks is shown.
Abstract: Recent results on GaAs-based high-speed mode-locked quantum-dot (QD) lasers and optical amplifiers with an operation wavelength centered at 1290 nm are reviewed and their complex dependence on device and operating parameters is discussed on the basis of experimental data obtained with integrated fiber-based QD device modules. Hybrid and passive mode locking of QD lasers with repetition frequencies between 5 and 80 GHz, sub-ps pulse widths, ultralow timing jitter down to 190 fs, high output peak power beyond 1 W, and suppression of Q-switching are reported, showing the large potential of this class of devices for O-band optical fiber applications. Results on cw and dynamical characterization of QD semiconductor optical amplifiers (SOAs) are presented. QD amplifiers exhibit a close-to-ideal noise figure of 4 dB and demonstrate multiwavelength amplification of three coarse wavelength division multiplexing (CWDM) wavelengths simultaneously. Modelling of QD polarization dependence shows that it should be possible to achieve polarization insensitive SOAs using vertically coupled QD stacks. Amplification of ultrafast 80 GHz optical combs and bit-error-free data signal amplification at 40 Gb/s with QD SOAs show the potential for their application in future 100 Gb Ethernet networks.

Journal ArticleDOI
TL;DR: In this paper, a plug-and-play source of single photons, with full integration to a singlemode optical fiber, was presented, where one end of the fiber is attached to the top of an InGaAs∕GaAs quantum dot wafer, and the other end is connected via a wavelength-division multiplexing system to two separate fibers: one for carrying excitation light and other for emitted light.
Abstract: The authors report a “plug and play” source of single photons, with full integration to a single-mode optical fiber One end of the fiber is attached to the top of an InGaAs∕GaAs quantum dot wafer The other end is connected via a wavelength-division multiplexing system to two separate fibers: one for carrying excitation light and the other for emitted light A Hanbury-Brown and Twiss [Nature (London) 77, 27 (1956)] measurement was performed on the emission from single excitons recombining in the quantum dots A second-order correlation function at zero time delay of approximately 001 indicates a nearly ideal source of single photons The maximum variation of peak position over 24days is less than 01nm

Journal ArticleDOI
S. Y. Kim1, S. B. Jun1, Yuichi Takushima1, E. S. Son1, Yun Chur Chung1 
TL;DR: In this article, the authors demonstrate that the power budget and scalability of the WDM PON implemented by using reflective semiconductor optical amplifiers (RSOAs) can be significantly improved by modulating the downstream signals in Manchester format instead of the conventional non-return-to-zero format.
Abstract: Feature Issue on Passive Optical Network Architectures and TechnologiesWe propose and demonstrate that the power budget and scalability of the wavelength-division-multiplexed passive optical network (WDM PON) implemented by using reflective semiconductor optical amplifiers (RSOAs) can be significantly improved by modulating the downstream signals in Manchester format instead of the conventional non-return-to-zero format. As an example, we experimentally show that the maximum transmission distance of the RSOA-based WDM PON can be increased by a factor of 2 by using the Manchester-encoded downstream signals.