By Topic

Lightwave Technology, Journal of

Issue 23 • Date Dec.1, 2009

Filter Results

Displaying Results 1 - 25 of 43
  • [Front cover]

    Page(s): C1
    Save to Project icon | Request Permissions | PDF file iconPDF (370 KB)  
    Freely Available from IEEE
  • Journal of Lightwave Technology publication information

    Page(s): C2
    Save to Project icon | Request Permissions | PDF file iconPDF (38 KB)  
    Freely Available from IEEE
  • Table of contents

    Page(s): 5221 - 5222
    Save to Project icon | Request Permissions | PDF file iconPDF (48 KB)  
    Freely Available from IEEE
  • Shear Strain Influence on Fiber Bragg Grating Measurement Systems

    Page(s): 5223 - 5229
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (594 KB) |  | HTML iconHTML  

    Fiber Bragg grating (FBG) sensors have become commercially available sensors for the measurement of temperature, strain, and many other quantities. One interesting application is the embedding of these sensors, during which shear strains can arise inside the sensor. As we have recently demonstrated by a full-tensor coupled-mode analysis, shear strains do influence the spectral response of fiber Bragg sensors, and thus have to be considered. In this paper, we use the theory behind this analysis to compute the direct influence of shear strains on the output of a FBG measurement system, and show cases where shear strain effects are relevant. Furthermore, we compare the sensitivity of different interrogation algorithms toward shear strain influences on the measurement system output. To model the experimentally relevant unpolarized light sources, we derive a model using the monochromatic waves of coupled-mode theory. We apply the unpolarized light to the FBG shear strain problem and show that for unpolarized light, shear strain has to be taken into account as well. We find absolute measurement errors in the range of 100 pm. For typical normal strain measurements, this would be of an order of 10% of relative error. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Key Agreement Protocol Using Band-Limited Random Signals and Feedback

    Page(s): 5230 - 5234
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (157 KB) |  | HTML iconHTML  

    Key distribution is an essential element in cryptography. In this paper, the framework of a classical key agreement protocol using band-limited random signals and feedback is presented. The secrecy is derived from masking information by privately held random signals. Critical parameters of the protocol are identified. Raw performance of the system is presented. The secrecy can be enhanced by taking advantages of measures, such as reconciliation and privacy amplification, developed for classical and quantum key agreement protocols. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Coupling Theoretical Model Between Single-Core Fiber and Twin-Core Fiber

    Page(s): 5235 - 5239
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (606 KB) |  | HTML iconHTML  

    In this paper, a simple theoretical model for describing the coupling between a single-core single-mode fiber and a twin-core single-mode fiber is established. The coupling processing of the two light beams is given and the theoretical predictions are confirmed by the experimental results. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Cavity-Enhanced IR Absorption in Planar Chalcogenide Glass Microdisk Resonators: Experiment and Analysis

    Page(s): 5240 - 5245
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (394 KB) |  | HTML iconHTML  

    Planar microdisk optical resonators fabricated from Ge23Sb7S70 chalcogenide glass on a silicon substrate are applied for cavity-enhanced spectroscopic measurement of chemical molecular absorption fingerprint. A 0.02 cm- 1 detection limit for these devices is demonstrated. This detection limit represents a threefold improvement as compared to a straight waveguide sensor, while the physical device length is reduced by 40-fold. The reduction in device footprint with enhanced sensitivity makes the structure attractive for ldquosensor-on-a-chiprdquo device applications. We also present a design optimization approach for cavity-enhanced IR absorption spectroscopy using traveling-wave resonators, which indicates that further performance improvement can be achieved in optimally coupled, low-loss resonant cavities. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Simultaneous Optical Pulse Multiplication and Shaping Based on the Amplitude-Assisted Phase-Only Filter Utilizing a Fiber Bragg Grating

    Page(s): 5246 - 5252
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (981 KB) |  | HTML iconHTML  

    A novel all-optical simultaneous pulse multiplication and shaping approach is proposed, which is based on the simultaneous utilization of two amplitude-assisted phase-only spectral filters realizable by using a short fiber Bragg grating. This proposed method enables to create a high-repetition-rate rectangular pulse train with both an ideal rectangular envelop and a high energy efficiency. As a particular example, a repetition rate of 90 GHz rectangular pulse train is numerically demonstrated from an initial 10 GHz Gaussian pulse train. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Wavelength-Swept Super-Dense Wavelength-Division Multiplexing (SD-WDM) Transmitter: Theoretical and Experimental Study of Performance Degradation Caused by Interchannel Crosstalk

    Page(s): 5253 - 5260
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (894 KB) |  | HTML iconHTML  

    This paper presents a theoretical and experimental study of performance degradation caused by the interchannel crosstalk of a previously proposed scheme for a super-dense wavelength-division multiplexing (WDM) transmitter based on wavelength-swept light. In the theoretical study, we calculate the relationship between the optical filter bandwidth, the wavelength sweep range, and the power penalty based on an approximate modeling process. And we employ the results to clarify the number of channels that can be achieved without a serious power penalty for use as a practical criterion when the wavelength sweep range is given. Furthermore, we describe experiments on multichannel 100 Mb/s and 1.0 Gb/s WDM signal generation and selective detection using a fiber Bragg grating filter with a 3-dB bandwidth of 10.5 GHz. The results confirm that the theoretical and the experimental results agree well when the spectral broadening induced by data modulation is not very large. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High-Rate Nonbinary Regular Quasi-Cyclic LDPC Codes for Optical Communications

    Page(s): 5261 - 5267
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (546 KB) |  | HTML iconHTML  

    The parity-check matrix of a nonbinary (NB) low-density parity-check (LDPC) code over Galois field GF(q) is constructed by assigning nonzero elements from GF(q) to the 1s in corresponding binary LDPC code. In this paper, we state and prove a theorem that establishes a necessary and sufficient condition that an NB matrix over GF(q), constructed by assigning nonzero elements from GF(q) to the 1s in the parity-check matrix of a binary quasi-cyclic (QC) LDPC code, must satisfy in order for its null-space to define a nonbinary QC-LDPC (NB-QC-LDPC) code. We also provide a general scheme for constructing NB-QC-LDPC codes along with some other code construction schemes targeting different goals, e.g., a scheme that can be used to construct codes for which the fast-Fourier-transform-based decoding algorithm does not contain any intermediary permutation blocks between bit node processing and check node processing steps. Via Monte Carlo simulations, we demonstrate that NB-QC-LDPC codes can achieve a net effective coding gain of 10.8 dB at an output bit error rate of 10-12. Due to their structural properties that can be exploited during encoding/decoding and impressive error rate performance, NB-QC-LDPC codes are strong candidates for application in optical communications. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Reconfigurable All-Optical Logic Gates for Multi-Input Differential Phase-Shift Keying Signals: Design and Experiments

    Page(s): 5268 - 5275
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1017 KB) |  | HTML iconHTML  

    Differential phase-shift keying (DPSK) signals are promising candidate for the long-haul transmission systems. However, the development of the all-optical signal processing techniques for the DPSK signals is still in its infancy, especially the all-optical logic operations. In this work, a general scheme for reconfigurable logic gates for multi-input DPSK signals with integration possibility is proposed. Benefiting from the optical logic minterms developed by two kinds of optical devices, i.e., optical delay interferometers and semiconductor optical amplifiers (SOAs), target logic functions can be realized by combining specific minterms together. The scheme is reconfigured by changing the phase control of the delay interferometers or the input wavelengths. The latter approach was adopted in the experimental trials. Although the outputs of the scheme are on-off keying (OOK) signals, the data format is compatible with all-optical decision circuits where OOK format is preferred. Two- and three-input experiments are carried out at 20 Gbit/s with nonreturn-to-zero DPSK signals. Various logic operations are demonstrated, including full sets of two- and three-input minterms, AND, NOR, XOR, and XNOR logic operations where the AND and NOR logic are derived simultaneously and the XOR and XNOR logic are convertible. The optical SNR as well as the Q-factor of the two- and three-input results are measured and compared. It shows that the input powers to the SOAs are critical in achieving good extinction ratio and the Q-factor of logic results degrades when several minterms are combined. The recovery time of the SOAs need to be optimized as well. Finally, the scaling issues of the scheme are discussed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Generation of Arbitrary UWB Waveforms by Spectral Pulse Shaping and Thermally-Controlled Apodized FBGs

    Page(s): 5276 - 5283
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1299 KB) |  | HTML iconHTML  

    We propose and experimentally demonstrate an arbitrary UWB pulse generator. The proposed technique is based on spectral pulse shaping and frequency-to-time conversion. The reconfigurability of this technique comes from changing the apodizaton of a chirped fiber Bragg grating (FBG) using a series of heating elements (HE). By setting the appropriate temperature set to the HEs, any predesigned UWB waveforms can be generated with high precision. The effective isotropically radiated power (EIRP)-optimized and U.S. Federal Communications Commission (FCC)-optimized pulses as well as the traditional Gaussian monocycle and doublet UWB waveforms are generated which are in excellent match with the designed target pulse shapes. While other arbitrary pulse generators have used similar strategies (spectral shaping and frequency-to-time conversion), ours uses inexpensive technologies with the potential for practical, compact packaging. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Employing Code Domain for Contention Resolution in Optical Burst Switched Networks With Detailed Performance Analysis

    Page(s): 5284 - 5294
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1021 KB) |  | HTML iconHTML  

    We propose the implementation of spectral-amplitude-coding optical code division multiple access (SAC-OCDMA) as a contention resolution technique in optical burst switched (OBS) networks. The new system architecture is presented in details where an all-optical methodology for cancelling multiple access interference is proposed. Performance evaluation of the proposed system in both MAC and optical layers is introduced where the overall burst error rate of the system is evaluated in three cases: full, partial, and no code conversion capabilities taking into account the receiver dark current, thermal, and shot noises at the egress nodes. Our results reveal that a considerable improvement in the performance of each core node in the system is achieved by using SAC-OCDMA instead of WDM in the optical layer underneath an OBS based MAC layer. We also conclude that a slight increase in the employed number of code converters enhances the overall system performance noticeably. Finally, optimum values for the number of codes, which lead to minimum overall burst error rate, are reached at different traffic conditions. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • NRZ-DPSK and RZ-DPSK Signals Signed Chromatic Dispersion Monitoring Using Asynchronous Delay-Tap Sampling

    Page(s): 5295 - 5301
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1779 KB) |  | HTML iconHTML  

    In this paper, we demonstrated a signed chromatic dispersion (CD) monitoring method of 10 GHz nonreturn-to-zero differential phase-shift keying (NRZ-DPSK) and return-to-zero differential phase-shift keying (RZ-DPSK) signals by using asynchronous delay-tap sampling and an imperfect tuned delay interferometer. This method could monitor not only the value but also the polarity of residual CD. The demodulated signals show amplitude shoulders on the rising edge or the trailing edge with CD accumulation. Delay-tap sampling scatter plots could reflect this signal distortion by a unique characteristic and realize the signed CD monitoring. The monitoring range can be up to plusmn400 and plusmn720 ps/nm for NRZ-DPSK and RZ-DPSK signals, respectively. Simulation and experimental results are also proposed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Thermal Properties of 12-Fold Quasi-Photonic Crystal Microcavity Laser With Size-Controlled Nano-Post for Electrical Driving

    Page(s): 5302 - 5307
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1003 KB) |  | HTML iconHTML  

    In this report, we investigate the fabrication process of 12-fold quasi-photonic crystal microcavity with size-controlled nano-post beneath for electrically-driven structure by fine-tuning the wet-etching time. By finite-element method, we simulate and analyze the heat transfer behaviors of microcavities with different nano-post sizes and shapes. From the real devices, we obtain whispering-gallery (WG) single-mode lasing action with high measured quality factor of 8 250 and low threshold of 0.6 mW when the nano-post size is as large as 830 nm in diameter. By varying the substrate temperature, WG single-mode lasing action is still obtained when the substrate temperature is as high as 70degC. Besides, the lasing wavelength red-shift rate is also improved compared with the microcavity without nano-post beneath. By varying the pump condition, lasing action is still observed at room temperature when the pump duty cycle increases to 16.0%. Thus, for electrically-driven photonic crystal microcavity lasers, this nano-post can serve as current injection pathway and heat sink at the same time. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fabrication of Self-Organized Optical Waveguides in Photo-induced Refractive Index Variation Sol–Gel Materials With High-Index Contrast

    Page(s): 5308 - 5313
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (843 KB) |  | HTML iconHTML  

    Using photo-induced refractive index variation sol-gel materials, we fabricated a self-organized lightwave network (SOLNET), which is a concept of optical waveguides self-organized in photosensitive materials, whose refractive index increases by write beam exposure. The refractive index of the sol-gel materials increases from 1.65 to 1.85 when exposed to UV light/blue light and baking. When write beams with a wavelength of 405 nm are introduced into the sol-gel thin film under baking at 200degC, self-focusing is induced and a SOLNET is formed. In this study, we evaluated the light confinement effect and coupling efficiencies of the fabricated SOLNET. The half-width of the output beam spot decreases from 23.8 to 11.8 mum, and the coupling efficiencies increase as write beam intensity decreases from 1.0 to 0.1 mW. These results show that SOLNET widths become narrow when write beam intensity is reduced; thus, SOLNETs formed with a low write beam intensity produce a strong light confinement effect. Furthermore, during their formation, SOLNETs were found to be drawn toward reflective portions of the sol-gel thin film, such as defects or silver paste droplets, indicating that a reflective SOLNET is formed. We have shown that photo-induced refractive index variation sol-gel materials are promising materials for SOLNET fabrication. To create actual connections between nanoscale optical circuits, further work is necessary to optimize the baking temperature and write beam intensity required for nanoscale SOLNET formation. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Instantaneous Microwave Frequency Measurement With Improved Measurement Range and Resolution Based on Simultaneous Phase Modulation and Intensity Modulation

    Page(s): 5314 - 5320
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (591 KB) |  | HTML iconHTML  

    A novel approach to implementing instantaneous microwave frequency measurement based on simultaneous optical phase modulation and intensity modulation with improved measurement range and resolution is proposed and experimentally demonstrated. The simultaneous optical phase modulation and intensity modulation are implemented using a polarization modulator (PolM) in conjunction with an optical polarizer. The phase- and intensity-modulated optical signals are then sent to a dispersive element, to introduce chromatic dispersions, which results in two complementary dispersion-induced power penalty functions. The ratio between the two power penalty functions has a unique relationship with the microwave frequency. Therefore, by measuring the microwave powers and calculating the power ratio, the microwave frequency can be estimated. Thanks to the complementary nature of the power penalty functions, a power ratio having a faster change rate versus the input frequency, i.e., a greater first-order derivative, is resulted, which ensures an improved measurement range and resolution. The proposed approach for microwave frequency measurement of a continuous-wave and a pulsed microwave signal is experimentally investigated. A frequency measurement range as large as 17 GHz with a measurement resolution of plusmn 0.2 GHz for a continuous-wave microwave signal and plusmn0.5 GHz for a pulsed microwave signal is achieved. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The Nonlinear Impairments Due to the Data Correlation Among Sub-Carriers in Coherent Optical OFDM Systems

    Page(s): 5321 - 5326
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (748 KB) |  | HTML iconHTML  

    Resulted from the narrow frequency interval, the nonlinear impairments are strongly related with the data correlation of the optical orthogonal frequency division (OFDM) symbol in coherent optical OFDM (CO-OFDM) system, which is very different from the traditional WDM optical communication systems. The concept of normalized accumulative correlation coefficient (NACC) is proposed to evaluate the data correlation of the OFDM symbol. The parameter phi is presented to describe the influence of the systematic physical configuration on the nonlinear impairments. The dependence of the nonlinear impairments on the data correlation is investigated and revealed analytically. Closed form expressions are presented to calculate the noise spectrum, total nonlinear noise energy and noise signal ratio (NSR) under the condition that phi les 0.2, which is valid for most practical CO-OFDM system. The NSR is proportional to the NACC and phi2. Simulation results are well consistent with analytical calculations when phi les 0.2. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Full-Field Electronic Dispersion Compensation of a 10 Gbit/s OOK Signal Over 4 ,\times, 124 km Field-Installed Single-Mode Fibre

    Page(s): 5327 - 5335
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (834 KB) |  | HTML iconHTML  

    We experimentally demonstrate the use of full-field electronic dispersion compensation (EDC) to achieve a bit error rate of 5times10- 5 at 22.3 dB optical signal-to-noise ratio for single-channel 10 Gbit/s on-off keyed signal after transmission over 496 km field-installed single-mode fibre with an amplifier spacing of 124 km. This performance is achieved by designing the EDC so as to avoid electronic amplification of the noise content of the signal during full-field reconstruction. We also investigate the tolerance of the system to key signal processing parameters, and numerically demonstrate that single-channel 2160 km single mode fibre transmission without in-line optical dispersion compensation can be achieved using this technique with 80 km amplifier spacing and optimized system parameters. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A New Method for Blocking Probability Evaluation in OBS/OPS Networks With Deflection Routing

    Page(s): 5335 - 5347
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (787 KB) |  | HTML iconHTML  

    In this paper, we present a new method for the estimation of blocking probabilities in bufferless optical burst or packet switched networks. In such networks, deflection routing is used to reduce blocking probability. However, it requires certain wastage due to trunk reservation that must be used to avoid instability. We provide a wide range of simulation and numerical results to validate our new approximation method and demonstrate various effects on blocking probability and utilization, such as network size, trunk size, the maximal number of allowable deflections, and burst/packet length. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Asymmetric Half-Wave Plate Configuration of PLC Mach–Zehnder Interferometer for Polarization Insensitive DQPSK Demodulator

    Page(s): 5348 - 5355
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (505 KB) |  | HTML iconHTML  

    We propose a novel polarization dependent frequency shift (PDf) reduction method for fabricating a silica-based PLC DQPSK demodulator incorporating an asymmetrically positioned half-wave plate, and demonstrate error-free 43-Gbit/s demodulation for any incident SOP. The PDf has a detrimental effect on the demodulation performance of a DQPSK signal, and it is degraded by various kinds of PLC fabrication errors. In this paper, we focus on the polarization crosstalk in the coupler, which is one of the main causes of PDf. To eliminate such PDf, we controlled both the position of the half-wave plate in the MZI and the polarization of the propagated light. We describe the principle of this PDf reduction method in detail and provide a theoretical and experimental discussion. In addition, we describe a compact DQPSK demodulator composed of a single MZI based DQPSK demodulator with a 90-degree optical hybrid. This demodulator configuration can reduce the receiver's footprint. Finally we achieved a compact DQPSK demodulator with a low PDf of less than 0.10 GHz in the L-band. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multipoint Chemical Gas Sensing Using Frequency-Shifted Interferometry

    Page(s): 5356 - 5364
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (768 KB) |  | HTML iconHTML  

    We apply frequency-shifted interferometry to interrogate multiple gas sensors along a single fiber. This method uses a tunable continuous-wave laser and a slow detector, and allows spectral overlap of sensors. It can be used to quantify the concentrations of single or different gas species at multiple locations. A three-sensor system was used to demonstrate this capability, achieving a minimum detectable acetylene concentration of 230 ppm with a 3-cm gas cell, or equivalently, 6.9 ppmmiddot m. The design considerations in the implementation and the system parameters are also discussed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Thermally Tunable All-Fiber Filter Based on Two Series Connected Sagnac Interferometers With Different Loop Lengths

    Page(s): 5365 - 5369
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB) |  | HTML iconHTML  

    In this paper, the characterization of a thermally tunable fiber optic filter is presented. It consists of two Sagnac interferometers (SIs) connected in series. Each SI contains a high-birefringence fiber (HiBiFi) segment with different length in the loop, which generates a reduction in the bandwidth of the filter transmission peak. In a previous work, a filter composed by two SIs with equal HiBiFi segments connected in series was reported. An experimental bandwidth reduction of approximately 31%, compared with a filter composed by a single SI was obtained. Using the configuration proposed in the present work, a reduction of approximately 52% in the range of 1533 to 1586 nm and a sensitivity of -1.27 nm/degC was obtained. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • All-Optical Asynchronous Detection for a Compact Integrable Incoherent Optical CDMA System

    Page(s): 5370 - 5375
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (991 KB) |  | HTML iconHTML  

    In this paper, we investigate all-optical truly asynchronous detection without global clocking in an incoherent optical code-division multiple-access (CDMA) system. The implemented system is designed with an integrable optical source consisting of an electro-absorption modulator for pulse carving, compact coders consisting of fiber Bragg grating arrays for encoding and decoding, and receiver consisting of an all-optical thresholder for data and clock recovery. We compare three detection schemes: (1) synchronous detection with data from a photodetector and clock from an external source; (2) asynchronous detection with data and clock from the all-optically thresholded signal received by a clock and data recovery (CDR) unit; and (3) asynchronous detection with data from a photodetector and clock extracted from the all-optically thresholded signal using CDR. Error-free transmission is obtained for detection schemes (1) and (3). A combination of all-optical thresholding and CDR technology is demonstrated in an optical CDMA system for the first time. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optical Coding for Enhanced Real-Time Dynamic Bandwidth Allocation in Passive Optical Networks

    Page(s): 5376 - 5384
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1048 KB) |  | HTML iconHTML  

    In this paper, optical pulse encoding and decoding technology is proposed to enable real-time signaling in a passive optical network (PON) setting. Unique optical codes are assigned to selected optical network units (ONUs) equipped with the corresponding encoders. An out-of-band pulse train is broadcast from the optical line terminal (OLT) and is modulated by ONU-based switches. The encoded reflections of pulses are thus used to update the status of the OC-enabled queues at the OLT in real time. We explore the enhanced PON architecture and define its major design parameters. Through extensive simulations, we investigate the design principles and limits of our system parameters. Through a performance comparison of native interleaved polling with adaptive cycle time with its OC-enhanced counterpart, we show that our OC enhancement breaks the fundamental delay lower bound associated to the polling cycle. We propose and investigate new dynamic bandwidth allocation (DBA) algorithms that exploit real-time queue updates enabled through OC-enhanced polling. We also explore the pay-as-you-grow implementation of OC-enhanced polling to realize quality-of-service (QoS) differentiation, elaborate on possible migration paths from conventional PONs, and investigate absolute QoS performance guarantee improvements achieved through OC-enabled real-time DBA algorithms. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

The Journal of Lightwave Technology contains articles on current research, applications and methods used in lightwave technology and fiber optics.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Peter J. Winzer
Alcatel-Lucent Bell Labs