Showing papers on "Wavelength-division multiplexing published in 2008"
01 Jan 2008
TL;DR: In this paper, the use of a coherent digital receiver for compensation of linear transmission impairments and polarization demultiplexing in a transmission system compatible with a future 100-Gb/s Ethernet standard is discussed.
Abstract: We discuss the use of a coherent digital receiver for the compensation of linear transmission impairments and polarization demultiplexing in a transmission system compatible with a future 100-Gb/s Ethernet standard. We present experimental results on the transmission performance of 111 Gbit/s POLMUX-RZ-DQPSK. For a dense WDM setup with channels carrying 111 Gbit/s with a 50 GHz channel spacing (2.0 bits/s/Hz), we show the feasibility of 2375 km transmission. This is enabled through coherent detection which results in excellent noise performance, and subsequent electronic equalization which provides the high tolerance to polarization mode dispersion and chromatic dispersion (CD). Furthermore, we discuss the impact of sampling and digital signal processing with either 1 or 2 samples/bit. We show that when combined with low-pass electrical filtering, 1 sample/bit signal processing is sufficient to obtain a large tolerance towards CD. The proposed modulation and detection techniques enable 111 Gbit/s transmission that is directly compatible with the existing 10 Gbit/s infrastructure.
405 citations
TL;DR: A universal post-compensation scheme for fiber impairments in wavelength-division multiplexing (WDM) systems is proposed based on coherent detection and digital signal processing (DSP).
Abstract: A universal post-compensation scheme for fiber impairments in wavelength-division multiplexing (WDM) systems is proposed based on coherent detection and digital signal processing (DSP). Transmission of 10 x 10 Gbit/s binary-phase-shift-keying (BPSK) signals at a channel spacing of 20 GHz over 800 km dispersion shifted fiber (DSF) has been demonstrated numerically.
369 citations
12 Feb 2008
TL;DR: In this article, the phase front of the optical signal inside the wavelength selective switch is adjusted to compensate for various amounts of dispersion (up to ± 60 ps/nm), tunable for each wavelength division multiplexed channel.
Abstract: We experimentally demonstrate dispersion compensation in a wavelength selective switch, and characterize the bandwidth-dispersion product. At a channel bit-rate of 80 Gbit/s, we compensate for various amounts of dispersion (up to ±60 ps/nm), tunable for each wavelength division multiplexed channel, solely by adjusting the phase front of the optical signal inside the wavelength selective switch. Error-free operation is obtained for all of the channels, and for each output port after propagation over various lengths of dispersive fiber.
269 citations
TL;DR: The realization and performance of polarization-division-multiplexed orthogonal frequency division multiplexing (PDM-OFDM) for long-haul transmission systems is discussed and MIMO processing in the receiver enables both polarization demultiplexing and a large PMD tolerance.
Abstract: Focus Issue on Orthogonal-Frequency-Division Multiplexed Communications Systems and Networks We discuss the realization and performance of polarization-division-multiplexed orthogonal frequency division multiplexing (PDM-OFDM) for long-haul transmission systems. Polarization demultiplexing of the PDM signal at the receiver is realized by employing a multiple-input multiple-output (MIMO) detector. Using a recirculating loop a long-haul transmission experiment is reported of 52.5 Gbits/s PDM-OFDM (40 Gbits/s after coding) over 4160 km of standard single-mode fiber (SSMF). In this transmission experiment, 16 wavelength-division-multiplexed (WDM) channels are transmitted at 50 GHz channel spacing, and we show that MIMO processing in the receiver enables both polarization demultiplexing and a large PMD tolerance.
207 citations
Patent•
16 Oct 2008TL;DR: In this article, the authors proposed a WDM PON system in which an optical signal outputted from a central office is injected into a Fabry-Perot laser diode (F-P LD) as the light source of an optical network unit.
Abstract: Disclosed is a wavelength division multiplexing passive optical network (WDM PON) system in which an optical signal outputted from a central office is injected into a Fabry-Perot laser diode (F-P LD) as the light source of an optical network unit, so that the output wavelength of the optical network unit is injection-locked at the same wavelength as that of the optical signal outputted from the central office, thereby enabling the optical network unit to output an optical signal having the same wavelength as that of the optical signal outputted from the central office. In accordance with this system, it is possible to transmit and receive forward and backward data at the same wavelength by the unit of channels. Since inexpensive F-P LDs are used as respective light sources of the central office and optical network units, it is possible to efficiently and economically implement a WDM PON system.
177 citations
TL;DR: The results show that the RSOA-based WDM PON is operable at 10 Gb/s and the maximum reach can be extended to >20 km with the help of the forward error correction codes.
Abstract: We report on the 1O-Gb/s operation of the reflective semiconductor optical amplifier (RSOA) for the next-generation wavelength-division-multiplexed passive optical network (WDM PON). The bandwidth of the RSOA used in this experiment is merely 2.2 GHz. Nevertheless, a clear eye opening is obtained at 10 Gb/s by using the electronic equalizer processed offline. We investigate the impacts of the network's operating conditions (such as the injection power to the RSOA and the fiber length) on the performances of these equalizers. The results show that the RSOA-based WDM PON is operable at 10 Gb/s and the maximum reach can be extended to >20 km with the help of the forward error correction codes.
173 citations
01 Jan 2008
TL;DR: In this article, the authors demonstrate record 25.6-Tb/s transmission over 240 km using 160 WDM channels on a 50GHz grid in the C+L bands, each channel contains two polarization-multiplexed 85.4-Gb/s RZ-DQPSK signals.
Abstract: We demonstrate record 25.6-Tb/s transmission over 240 km using 160 WDM channels on a 50-GHz grid in the C+L bands. Each channel contains two polarization-multiplexed 85.4-Gb/s RZ-DQPSK signals, yielding a spectral efficiency of 3.2b/s/Hz in each band.
162 citations
TL;DR: In this article, the frequency of an ultra-stable laser over 86 km of urban fiber was transferred and the link was composed of two cascaded 43-km fibers connecting two laboratories, LNE-SYRTE and LPL in Paris area.
Abstract: We transferred the frequency of an ultra-stable laser over 86 km of urban fiber. The link is composed of two cascaded 43-km fibers connecting two laboratories, LNE-SYRTE and LPL in Paris area. In an effort to realistically demonstrate a link of 172 km without using spooled fiber extensions, we implemented a recirculation loop to double the length of the urban fiber link. The link is fed with a 1542-nm cavity stabilized fiber laser having a sub-Hz linewidth. The fiber-induced phase noise is measured and cancelled with an all fiber-based interferometer using commercial off the shelf pigtailed telecommunication components. The compensated link shows an Allan deviation of a few 10-16 at one second and a few 10-19 at 10,000 seconds.
159 citations
TL;DR: In this article, the authors investigate the signal integrity in silicon photonic nanowire waveguides for wavelength-division-multiplexed optical signals and demonstrate the feasibility of ultra-high-bandwidth integrated photonic networks by transmitting a 1.28-Tb/s data stream (32 wavelengths times 40-Gb/s) through a 5-cm-long silicon wire.
Abstract: An investigation of signal integrity in silicon photonic nanowire waveguides is performed for wavelength-division-multiplexed optical signals. First, we demonstrate the feasibility of ultrahigh-bandwidth integrated photonic networks by transmitting a 1.28-Tb/s data stream (32 wavelengths times 40-Gb/s) through a 5-cm-long silicon wire. Next, the crosstalk induced in the highly confined waveguide is evaluated, while varying the number of wavelength channels, with bit-error-rate measurements at 10 Gb/s per channel. The power penalty of a 24-channel signal is 3.3 dB, while the power penalty of a single-channel signal is 0.6 dB. Finally, single-channel power penalty measurements are taken over a wide range of input powers and indicate negligible change for launch powers of up to 7 dBm.
152 citations
TL;DR: In this article, a frequency quadrupling system using a single integrated Mach-Zehnder modulator without a narrowband optical filter was proposed to remove undesired optical sidebands.
Abstract: This letter demonstrates a novel method to generate high-purity optical millimeter-wave signals with carrier suppression by using a frequency quadrupling technique. To the authors' knowledge, this is the first time that a frequency quadrupling system requires only a single integrated Mach-Zehnder modulator without a narrowband optical filter to remove undesired optical sidebands. Since no optical filter is needed, fast frequency tuning is straightforward and this approach will be particularly attractive for optical up-conversion in wavelength-division-multiplexing radio-over-fiber systems. This letter provides both theoretical analysis and experimental demonstration. The generated optical millimeter-wave signals have very high quality with an optical carrier and harmonic distortion suppression ratio of more than 38 and 36 dB at 40 and 72 GHz, respectively.
146 citations
TL;DR: An analytic model of Coherent Optical Orthogonal Frequency Division Multiplexing (OFDM) propagation and detection over multi-span long-haul fiber links is developed, comprehensively and rigorously analyzing the impairments due the combined effects of FWM, Dispersion and ASE noise.
Abstract: We develop an analytic model of Coherent Optical Orthogonal Frequency Division Multiplexing (OFDM) propagation and detection over multi-span long-haul fiber links, comprehensively and rigorously analyzing the impairments due the combined effects of FWM, Dispersion and ASE noise. Consistent with prior work of Innoe and Schadt in the WDM context, our new closed-form expressions for the total FWM received power fluctuations in the wake of dispersive phase mismatch in OFDM transmission, indicate that the FWM contributions of the multitude of spans build-up on a phased-array basis. For particular ultra-long haul link designs, the effectiveness of dispersion in reducing FWM is far greater than previously assumed in OFDM system analysis. The key is having the dominant FWM intermodulation products due to the multiple spans, destructively interfere, mutually cancelling their FWM intermodulation products, analogous to operating at the null of a phased-array antenna system. By applying the new analysis tools, this mode of effectively mitigating the FWM impairment, is shown under specific dispersion and spectral management conditions, to substantially suppress the FWM power fluctuations. Accounting for the phased-array concept and applying the compact OFDM design formulas developed here, we analyzed system performance of a 40 Gbps coherent OFDM system, over standard G.652 fiber, with cyclic prefix based electronic dispersion compensation but no optical compensation along the link. The transmission range for 10-3 target BER is almost tripled from 2560 km to 6960 km, relative to a reference system performing optical dispersion compensation in every span (ideally accounting for FWM and ASE noise and the cyclic prefix overhead, but excluding additional impairments).
TL;DR: In this article, the authors discuss the generation, detection, and long-haul transmission of single-polarization differential quadrature phase shift keying (DQPSK) signals at a line rate of 53.5 Gbaud to support a net information bit rate of 100 Gb/s.
Abstract: We discuss the generation, detection, and long-haul transmission of single-polarization differential quadrature phase shift keying (DQPSK) signals at a line rate of 53.5 Gbaud to support a net information bit rate of 100 Gb/s. In the laboratory, we demonstrate 10-channel wavelength-division multiplexed (WDM) point-to-point transmission over 2000 km on a 150-GHz WDM grid, and 1200-km optically routed networking including 6 reconfigurable optical add/drop multiplexers (ROADMs) on a 100-GHz grid. We then report transmission over the commercial, 50-GHz spaced long-haul optical transport platform LambdaXtremereg. In a straight-line laboratory testbed, we demonstrate single-channel 700-km transmission, including an intermediate ROADM. On a field-deployed, live traffic bearing Verizon installation between Tampa and Miami, Florida, we achieve 500-km transmission, with no changes to the commercial system hardware or software and with 6 dB system margin. On the same operational system, we finally demonstrate 100-Gb/s DQPSK encoding on a field-programmable gate array (FPGA) and the transmission of real-time video traffic.
TL;DR: This work demonstrated ultra fast BB84 quantum key distribution transmission at 625 MHz clock rate through a 97 km field-installed fiber using practical clock synchronization based on wavelength-division multiplexing (WDM) and succeeded in over-one-hour stable key generation.
Abstract: We demonstrated ultra fast BB84 quantum key distribution (QKD) transmission at 625 MHz clock rate through a 97 km field-installed fiber using practical clock synchronization based on wavelength-division multiplexing (WDM). We succeeded in over-one-hour stable key generation at a high sifted key rate of 2.4 kbps and a low quantum bit error rate (QBER) of 2.9%. The asymptotic secure key rate was estimated to be 0.78–0.82 kbps from the transmission data with the decoy method of average photon numbers 0, 0.15, and 0.4 photons/pulse.
TL;DR: This work proposes and investigates a novel technique for the generation of millimeter-wave (mm-wave), i.e. frequency sixuplexing technique, comprised of two cascaded Mach- Zehnder modulators (MZMs), which leads to an 8-dB higher RF power at 60 GHz and a 6-dB improvement in receiver sensitivity with comparison to the conventional technique.
Abstract: In this work, we propose and investigate a novel technique for the generation of millimeter-wave (mm-wave), i.e. frequency sixuplexing technique. The proposed technique is comprised of two cascaded Mach-Zehnder modulators (MZMs). The first MZM, biased at maximum transmission, is only used for even-order optical harmonic generation, and then a second MZM, biased at minimum transmission, is used for both optical carrier suppression modulation and data signal modulation. As an example, we consider an RF at 10 GHz, which carries the data signal and drives the MZMs; and an mm-wave signal at 60 GHz, i.e. a frequency sixupler, is obtained. It is found that our proposed sixupler leads to an 8-dB higher RF power at 60 GHz and a 6-dB improvement in receiver sensitivity with comparison to the conventional technique, i.e. optical carrier suppression modulation. The generated mm-wave signal is robust to fiber chromatic dispersion. The proposed technique is verified by experiments.
TL;DR: This technique adds a new dimension to currently available multiplexing schemes and has the potential to increase the bandwidth of existing and futuristic optical fiber systems by multiple folds.
Abstract: A novel multiplexing technique for fiber optic communications has been developed that supports multiple channels of optical energy inside an optical fiber by confining each individual channel to a unique spatial location. These channels can operate at exactly the same wavelength as well as differing wavelengths. The basic operating principle and experimental results for spatial domain multiplexed fiber optic communication systems is presented here. This technique adds a new dimension to currently available multiplexing schemes and has the potential to increase the bandwidth of existing and futuristic optical fiber systems by multiple folds.
TL;DR: This work proposes and demonstrates a highly spectral efficient ER-PON using 4 Gb/s OFDM-QAM for both upstream and downstream signals, while achieving a high split-ratio of 256.
Abstract: In order to reduce the cost for delivering future broadband services, network operators are inclined to simplify the network architectures by integrating the metro and access networks into a single system. Hence, extended reach passive optical networks (ER-PONs) have been proposed. ER-PON usually has four new features: high data rate in both upstream and downstream signals (>1 Gb/s); reach extension to >100 km; a high split ratio (>100); and using wavelength division multiplexing (WDM). In this work, we propose and demonstrate a highly spectral efficient ER-PON using 4 Gb/s OFDM-QAM for both upstream and downstream signals, while achieving a high split-ratio of 256. The ER-PON employs optical components optimized for GPON (bandwidth of ∼1GHz) and reaches 100 km without dispersion compensation. Numerical analysis using 16, 64 and 256-QAM OFDM are also performed to study the back-to-back receiver sensitivities and power penalties at different electrical driving ratios.
12 Feb 2008
TL;DR: In this article, the tolerances to narrow optical filtering, chromatic dispersion, and polarization mode dispersion are investigated with coherent detection of 10-Gbaud quadrature phase shift keying (QPSK) with and without polarization division multiplexing.
Abstract: To provide higher capacity networks, 40-Gb/s transmission systems are under active development and their cost is on the way to be competitive with the one of 410 Gb/s. However, their lower tolerance to linear and nonlinear fiber impairments remains a major drawback for field deployment. To address the issue of linear impairments, coherent detection of multilevel formats with polarization division multiplexing appears as a promising solution by reducing the symbol rate to 10 Gbaud. Indeed, such coherent based systems have already demonstrated an improved tolerance to optical noise and an interesting capability to compensate for large amount of chromatic dispersion. In this paper, the tolerances to narrow optical filtering, chromatic dispersion, and polarization mode dispersion are investigated with coherent detection of 10-Gbaud quadrature phase shift keying (QPSK) with and without polarization division multiplexing. Moreover, the efficient mitigation of these linear impairments by digital processing in a coherent receiver is demonstrated in an ultralong haul transmission (4080 km) of 40-Gb/s QPSK polarization multiplexed data.
Patent•
22 Jan 2008TL;DR: In this paper, an optical-fiber amplifier with at least one erbium-doped fiber section and an optical pump coupled to the erbinium-free fiber section is described.
Abstract: An apparatus and that provide an optical-fiber amplifier having at least one erbium-doped fiber section and an optical pump coupled to the erbium-doped fiber section, wherein the apparatus is operable to amplify signal pulses to high energy in the erbium-doped fiber section, the pulses having a wavelength in the range of about 1565 nm to about 1630 nm. In some embodiments, the amplifying fiber is ytterbium free.
TL;DR: In this paper, the effect of the MZM nonlinearity and imbalanced y-splitter on optical mm-wave generation by DSBCS modulation is theoretically and experimentally investigated.
Abstract: Generation of optical millimeter-wave (mm-wave) signal using a Mach-Zehnder modulator (MZM) based on double-sideband (DSB), single-sideband (SSB), and double-sideband with carrier suppression (DSBCS) modulation schemes have been demonstrated for various applications, such as broadband wireless signals or optical up-conversion for wavelength-division-multiplexing (WDM) radio-over-fiber (RoF) network, wideband surveillance, spread spectrum, and software-defined radio. Among these schemes, DSBCS modulation offers the best receiver sensitivity, lowest spectral occupancy, the least stringent requirement of electrical bandwidth, and the smallest receiving power penalty after long transmission distance. Nonetheless, the inherent nonlinear E/O (electrical/optical) conversion response of a MZM is such that the signal quality of the optical mm-wave suffers. Fabrication tolerances make a balanced 50/50 splitting ratio of the MZM's y-splitter particularly difficult to achieve. As a result, imbalanced MZMs have a finite extinction ratio (ER) and degrade the optical carrier suppression ratio (OCSR) using DSBCS modulation. In this paper, the effect of the MZM nonlinearity and imbalanced y-splitter on optical mm-wave generation by DSBCS modulation is theoretically and experimentally investigated. A novel approach with better performance and greater cost-effectiveness than dual-electrode MZM (DD-MZM) is presented to realize a DSBCS modulation scheme based on a single-electrode MZM (SD-MZM).
TL;DR: A photonic implementation of a practical broadband RF Hilbert transformer is demonstrated by using a four-tap transversal system and extension of the transformer bandwidth and further improvements of its implementation are discussed.
Abstract: A photonic implementation of a practical broadband RF Hilbert transformer is demonstrated by using a four-tap transversal system. An almost ideal 90° phase shift with less than 3 dB of amplitude ripple has been achieved from 2.4 to 17.6 GHz. An efficient method to realize both transformed (quadrature-phase) and reference (in-phase) signal has been achieved by using a coarse wavelength division multiplexing coupler. Extension of the transformer bandwidth and further improvements of its implementation are discussed.
22 Dec 2008
TL;DR: The use of AMOOFDM format for remote modulation of low-bandwidth RSOA as a cost effective solution for 10 Gbit/s upstream transmission in 20 km single fiber WDM-PON architecture is experimentally demonstrated.
Abstract: We experimentally demonstrate the use of AMOOFDM format for remote modulation of low-bandwidth RSOA as a cost effective solution for 10 Gbit/s upstream transmission in 20 km single fiber WDM-PON architecture.
TL;DR: In this article, the potential of electronic dispersion compensation (EDC) in amplified multispan 111-Gb/s wavelength division multiplexed systems based on polarization-multiplexed quadrature phase-shift keying modulation with coherent detection was investigated.
Abstract: We carried out an extensive simulative analysis to investigate in depth the potential of electronic dispersion compensation (EDC) in amplified multispan 111-Gb/s wavelength- division-multiplexed systems based on polarization-multiplexed quadrature phase-shift keying modulation with coherent detection, also in the presence of substantial fiber nonlinearity. For typical single-mode and nonzero dispersion-shifted fibers, our results show that the use of inline optical dispersion management is always suboptimal versus using EDC at the receiver.
TL;DR: Enhanced upstream transmission at 10 Gb/s using a low-bandwidth reflective semiconductor optical amplifier is demonstrated and discussed for extended wavelength- division-multiplexing passive-optical-network applications.
Abstract: Enhanced upstream transmission at 10 Gb/s using a low-bandwidth reflective semiconductor optical amplifier is demonstrated and discussed for extended wavelength- division-multiplexing passive-optical-network applications. Significant improvement in terms of transmission performance is achieved with the use of electronic equalization and optimum filter offset placed at the receiver (optical line terminal) end only. According to filtering detuning, an analytical discussion is presented, explaining the bandwidth enhancement achieved with the proposed technique. The experimental studies consider the benefits of the electronic feed-forward and decision-feedback equalization as well as the required optimum offset optical filtering characteristics.
Patent•
25 Nov 2008TL;DR: In this article, a WDM-type PON system is proposed, where each ONU comprises an optical transmitter capable of transmitting optical signals with variable wavelengths, an optical signal receiving filter variable its receiving wavelength, and a control unit.
Abstract: In a WDM type PON system, each ONU comprises an optical transmitter capable to transmit optical signals with variable wavelengths, an optical signal receiving filter variable its receiving wavelength, and a control unit. An OLT selects in response to a wavelength allocation request from each ONU, a transmitting wavelength and a receiving wavelength out of currently free wavelengths and allocates these wavelengths to the requester ONT. The control unit of the ONU switches the transmitting wavelength of the optical transmitter and the receiving wavelength of the optical signal receiving filter to the wavelengths specified in a response message from the OLT and starts data communication.
24 Feb 2008
TL;DR: This paper presents an overview on the next generation PON techniques in which the developing trends of 10 G EPON, WDM-PON, hybrid WDM/TDM-Pon, long-reach PON and PON/RoF convergence are outlined.
Abstract: This paper presents an overview on the next generation PON techniques in which the developing trends of 10 G EPON, WDM-PON, hybrid WDM/TDM-PON, long-reach PON and PON/RoF convergence are outlined.
TL;DR: In this article, a distributed/discrete hybrid tellurite and silica-based fiber Raman amplifier (FRA) was constructed as an S + C + L band WDM repeater with a gain bandwidth of 127-nm.
Abstract: This paper reviews tellurite-based fibers and their applications to optical communication networks. First, an investigation of tellurite-based glass and the fabrication of conventional step-index fibers and photonic crystal fibers (PCF) are described. By purifying the raw materials and employing a novel PCF fabrication process, low background losses were achieved for an Er3+-doped, an undoped tellurite-based fiber and a tellurite-based PCF. Second, the optical properties of Er3+-doped tellurite-based glass and fiber, and the gain characteristics of erbium doped tellurite fiber amplifiers (EDTFAs) were studied. A seamless, low noise and gain flattened C + L band EDTFA was realized, and an S + C + L band amplifier was constructed by combining an EDTFA and a thulium-doped fluoride fiber amplifier (TDFFA) in parallel. Third, it is confirmed that the Raman scattering characteristic of tellurite-based fiber has such a large gain coefficient and Stokes shift that it is possible achieve a wideband tellurite-based fiber Raman amplifier. To overcome several problems, a distributed/discrete hybrid tellurite- and silica-based fiber Raman amplifier (FRA) was constructed as an S + C + L band WDM repeater with a gain bandwidth of 127-nm. Fourth, Brillouin amplification and the simulated performance of slow light generation in a tellurite-based fiber were investigated. The fiber exhibits the largest time delay per unit power of 19.9 ns/mW. Finally, a carrier-envelope offset (CEO)-locked frequency comb with low fiber coupling pulse energy (230 pJ) was demonstrated by using a tellurite-based PCF. This method has the potential to lock the CEO with a lower pulse energy and thus provide a low-noise and high-accuracy optical frequency comb at telecommunication wavelengths. These tellurite-based fibers with low background loss thus offer attractive functions for applications in the optical communication field.
22 Dec 2008
TL;DR: In this article, the authors demonstrate intradyne detection of 112-Gb/s 16-QAM (14-Gbaud, polarization-multiplexed) in a 10-channel WDM environment on a 25GHz grid.
Abstract: We demonstrate intradyne detection of 112-Gb/s 16-QAM (14-Gbaud, polarization-multiplexed) in a 10-channel WDM environment on a 25-GHz grid. We show the robustness of a central channel to multiple add/drop filtering and transmission over 315 km.
TL;DR: The proposed FBG sensing system, employing techniques of the wavelength- and spatial-domain interrogation of multiple FBGs, can be used in remote and quasi-distributed multipoint sensing.
Abstract: A novel fiber Bragg grating (FBG) sensing system based on a spectrum-limited Fourier domain mode-locking (SL-FDML) fiber laser is proposed. Multiple FBGs cascaded in a long fiber are utilized as both the sensors in the system and the wavelength-selected components in the SL-FDML fiber laser. Both wavelength-division multiplexing and spatial-division multiplexing techniques are demonstrated for interrogation of multiple FBGs by mapping the wavelength measurement to the time measurement and by adjusting the driving frequency of the SL-FDML fiber laser. The proposed FBG sensing system, employing techniques of the wavelength- and spatial-domain interrogation of multiple FBGs, can be used in remote and quasi-distributed multipoint sensing.
Patent•
08 Apr 2008TL;DR: In this article, a remodulating channel selector for a wavelength division multiplexed optical communication system is presented. But the selection of the optical channel is not a trivial task, since the wavelength of the output optical signal can be the same as or different from the optical channels which comprise the input signal.
Abstract: The present invention provides a remodulating channel selector for a wavelength division multiplexed optical communication system. The remodulating selector receives a WDM input signal, selects a particular optical channel from the WDM signal and places the information from the selected signal onto a newly-generated optical output signal. The wavelength of the output optical signal can be the same as or different from one of the optical channels which comprises the WDM input signal. When used in a WDM optical communication system with remodulators at the transmission input, the remodulating selectors provide complete control over the interfaces with optical transmitters and receivers, permitting use with a broad range of optical equipment.
01 Jan 2008
TL;DR: In this article, the measured wavelength division multiple access (WDM) performance and PMD tolerance of a coherent 40-Gbit/s dual-polarization quadrature phase shift keying (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 were evaluated.
Abstract: We report the measured wavelength-division-multiplexing (WDM) performance and polarization-mode dispersion (PMD) tolerance of a coherent 40-Gbit/s dual-polarization quadrature phase shift keying (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. We also evaluate the impact of polarization-dependent loss (PDL) on system performance and present the measured tolerance to frequency misalignment between the transmitter and a multiplexer/demultiplexer filter pair.