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Advanced Infocom Technology 2011 (ICAIT 2011), International Conference on

Date 11-14 July 2011

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Displaying Results 1 - 25 of 33
  • Technical program

    Publication Year: 2011 , Page(s): 8 - 16
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  • Performance optimization of passive mode-locked fiber ring laser

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (298 KB)  

    In this paper, firstly simulation program is used to simulate the performance of a passive mode-locked fiber ring laser. The result of the simulation shows how the two phenomena dispersion and nonlinearity affect the performance of a passive mode-locked ring laser. Hence, the performance of the passive mode-locked fiber ring laser can be optimized by setting proper dispersion and nonlinearity values. After that, a nonlinear polarization rotation (NPR) ring laser is constructed to verify the conclusions of the simulation. The conclusion from experiment matches the conclusion from simulations. Hence, the way to optimize the performance of the laser is found out and verified. Last but not least, during experiment part, the best pulse is obtained with pulse width 0.486ps, pulse bandwidth 5×107 GHz, pulse peak power 36.55 W and pulse power 315µW. View full abstract»

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  • In-band impairment measurement via Varied-SOP polarization-resolved Optical Spectrum Analysis

    Publication Year: 2011 , Page(s): 1 - 8
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1006 KB)  

    We review a novel measurement concept, based on the acquisition of multiple polarization-analyzed optical spectra corresponding to different polarization-analyzer orientations, or equivalently to varied states of polarization (SOPs) of the light impinging upon the analyzer. This approach denoted “Varied-SOP polarization-resolved Optical Spectrum Analysis” (VSOP-OSA), enables several types of in-band optical impairments to be quantified. In particular, it permits accurate and rapid measurement of optical signal to noise ratio (OSNR), differential group delay (DGD), and inter-channel-induced nonlinear effects (NLE) in term of NLE-induced signal depolarization. View full abstract»

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  • Novel L-band multiwavelength raman fiber laser based on three-stage mixed-cascaded phosphor-silicate Raman process

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (403 KB)  

    We experimentally demonstrate an L-band multiwavelength Raman fiber laser based on the three-mixed-cascaded stimulated Raman scattering (SRS) of both P2O5 and SiO2/GeO2 in a phosphosilicate fiber. A 1064 nm Yb3+-doped double-clad fiber laser (YDCFL) is used to pump a spool of 1-km phosphosilicate fiber. The three-stage mixed-cascaded Raman cavity is arranged as: 1) the 1st- and 2nd-order Raman cavities use the SRS of P2O5 and are formed by the two pairs of highly-reflective fiber Bragg gratings at 1239 and 1484 nm, respectively; 2) the 3rd-order Raman cavity uses the SRS of SiO2/GeO2 and is completed by a polarization-maintaining fiber (PMF) Sagnac comb filter and a broadband fiber loop mirror. When the injected pump power from YDCFL is 4.8 W, up to 12-wavelength stable oscillation around 1601 nm has been obtained with wavelength spacing of 0.58 nm and extinction ratio of >30 dB. View full abstract»

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  • Highly sensitive liquid-level sensor based on weak uniform fiber Bragg grating with narrow-bandwidth

    Publication Year: 2011 , Page(s): 1 - 3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (345 KB)  

    A highly sensitive liquid-level sensor based on weak uniform fiber Bragg grating (FBG) with narrow-bandwidth is proposed and demonstrated. The resonance wavelength varies as a result of axial strain change. According to this characteristic, a precise approach utilizing fiber grating as sensing element to measure height of liquid is achieved. The grating is directly bonded to a floater which can transfer floatage into axial strain on the fibre. Measurement of liquid level can be realized by monitoring the central wavelength shift of the sensing FBG. The experimental results show that for a liquid-level variation of 25 mm, a highly sensitivity of 6×10−6 m/pm with a good linearity is achieved, which is one of the best measuring accuracies ever reported. View full abstract»

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  • Tachkling mutual coupling in antenna arrays for wireless communications

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (171 KB)  

    A new model for tacking mutual coupling in wireless communications is introduced. A new concept of receiving mutual impedance is introduced and explained theoretically. Receiving mutual impedances for typical antenna arrays are obtained. Application of the new method is demonstrated in several arrays for direction finding, adaptive nulling, and MIMO communications. View full abstract»

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  • HF-PMIPv6: An enhanced fast handovers for network-based mobility management

    Publication Year: 2011 , Page(s): 1 - 7
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (144 KB)  

    Network-based mobility management overcomes the weakness of current host-based mobility management such as Mobile Node (MN) modification, signaling overhead and handover latency. In network-based mobility management, Fast Handovers for Proxy Mobile IPv6 (F-PMIPv6) improves packet loss for PMIPv6. However, in the F-PMIPv6 reactive mode, an MN performs handover before setting up a tunnel between the serving Mobile Access Gateway (i.e., P-MAG) and the target MAG (i.e., N-MAG). The P-MAG cannot forward the packets to the N-MAG without the tunnel and thus these packets are dropped by the P-MAG during handover. Moreover, the N-MAG establishes a tunnel to the P-MAG after the MN performs handover. The tunnel establishment increases the handover latency, the signaling cost and the tunnel transmission cost. To solve the above issues, we propose a Hybrid-mode Fast Handovers for PMIPv6 (HF-PMIPv6) mechanism. HF-PMIPv6 utilizes a decision table to detect the mobility mode (i.e., predictive or reactive). If the mobility mode is predictive, like F-PMIPv6, HF-PMIPv6 establishes a tunnel between the P-MAG and the N-MAG to prevent packet loss. On the contrary (i.e., in the reactive mode), HF-PMIPv6 performs handover directly without setting up a tunnel to reduce the extra handover latency, the signaling cost and the tunnel transmission cost. Since HF-PMIPv6 has the same performance as F-PMIPv6 in predictive mode, we evaluate the performance of HF-PMIPv6 and F-PMIPv6 in reactive mode in terms of the handover latency, the signaling cost and the packet delivery cost. View full abstract»

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  • Wavelength-tunable optical parametric regenerator

    Publication Year: 2011 , Page(s): 1 - 3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (93 KB)  

    In this invited talk, we will discuss the design of our proposed wavelength-tunable optical parametric regenerator and experimentally show its operation for 43-Gb/s RZ-OOK over a 20 nm input signal wavelength range. View full abstract»

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  • Bandwidth analysis of channelized tunable optical dispersion compensator based on liquid crystal on silicon

    Publication Year: 2011 , Page(s): 1 - 2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (85 KB)  

    Channelized tunable optical dispersion compensators (CTODCs) based on spatial light modulators (SLMs) are considered as enabling devices for future all optical high speed dynamic networks. This paper analyzes the relationship between CTODC bandwidth and its compensation range. Analytic expressions for the coupling loss spectrum of CTODC based on liquid-crystal on silicon (LCOS) are presented. These expressions can be useful tools for the bandwidth estimation and design of CTODC based on LCOS. View full abstract»

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  • Low-density parity-check codes used for polarization mode dispersion mitigation in 40-Gb/s optical fiber system

    Publication Year: 2011 , Page(s): 1 - 3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (411 KB)  

    Instead of Reed-Solomon (RS) code, Low-density parity-check (LDPC) codes are used with distributed fast polarization scramblers (FPSs) for polarization mode dispersion (PMD) mitigation in 40-Gb/s optical fiber system. The scrambling speed of FPS for LDPC (2040, 1903) codes system is discussed, the optimal speed 10MHz is obtained. The correction performance of LDPC codes are compared with RS codes. Results show the LDPC code can achieve a better performance than the RS (255, 239) code at a similar redundancy with soft decoding. View full abstract»

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  • Compensation of the frequency fluctuations of light sources in distributed Brillouin sensor

    Publication Year: 2011 , Page(s): 1 - 3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (331 KB)  

    Distributed sensor based on stimulated Brillouin scattering, especially Brillouin optical time-domain analysis (BOTDA) technique, attracts much interest recently due to its good performance of long sensing distance and high precision. In BOTDA system, the frequency fluctuation of the light sources is a serious problem, which will cause severe error of the measured Brillouin frequency shift (BFS), considering the narrow bandwidth of Brillouin spectrum. In this paper, a simple and low-cost method to compensate the error induced by frequency fluctuations of laser sources in a BOTDA system is proposed, by use of a local reference fiber which is loose and temperature monitored. The reference fiber, with several ten-meters long, can be part of the sensing fiber. Referring to the measured BFS of the reference fiber, one can obtain the errors induced by frequency fluctuations of light sources, and thus eliminate those errors. The proposed method is demonstrated by preliminary experiment. View full abstract»

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  • A hybrid image compression technique based on DWT and DCT transforms

    Publication Year: 2011 , Page(s): 1 - 8
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2638 KB)  

    In this paper, a hybrid technique using the discrete cosine transform (DCT) and the discrete wavelet transform (DWT) is presented. We show evaluation and comparative results for DCT, DWT and hybrid DWT-DCT compression techniques. Using the Power Signal to Noise Ratio (PSNR) as a measure of quality, we show that DWT with a two-threshold method named “improved-DWT” provides a better quality of image compared to DCT and to DWT with a one-threshold method. Finally, we show that the combination of the two techniques, named improved-DWT-DCT compression technique, showing that it yields a better performance than DCT-based JPEG in terms of PSNR. View full abstract»

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  • A novel discrete cosine transform algorithm for optimized hardware implementation in audio decoding

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (84 KB)  

    This paper presents a novel algorithm of discrete cosine transform (DCT) for digital theatre system (DTS) and windows media audio (WMA) decoding based on the type IV discrete cosine transform (DCT-IV). By virtue of the format conversion, the DTS and WMA decoding shares the same DCT-IV kernel, thus increasing the efficiency. The computation of DCT-IV is based on fast Fourier transform (FFT) and the coefficients are calculated in recursive algorithm. The performance of the proposed algorithm is compared with other reported algorithms. Both the efficiency of multiplication computation and the simplicity of hardware implementation are largely improved. View full abstract»

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  • Frequency-octupling millimeter-wave generation based on optical two-step self-heterodyne technique

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (562 KB)  

    A cost-effective frequency-quadrupling scheme which is capable of generating high frequency millimeter-wave (mm-wave) signal is theoretically proposed. By employing optical two-step self-heterodyne technique, this scheme is easy to realize and have a high efficiency. Base on this scheme, a frequency-octupling frequency component is generated. This proposed scheme is a viable solution for the future ultra-high frequency mm-wave applications. View full abstract»

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  • A new power control algorithm based on game theory in Cognitive Radio system

    Publication Year: 2011 , Page(s): 1 - 5
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (86 KB)  

    Power control is the key technology in Cognitive Radio (CR) systems. In this paper, we introduce the emergence of the problem for power control, analysis the theory of power control design problem basing on the cost function, redesign the cost function, put a new power control algorithm basing on game theory in cognitive radio networks, it can greatly improve the power control performance in the cognitive radio systems. View full abstract»

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  • A presentation deadline-based cross-layer design for IPTV services over wireless networks

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (255 KB)  

    Recently, IPTV services over Internet and wireless networks have been increasing rapidly. Hence, in this paper we introduce a presentation deadline-based cross-layer design for improving the QoS of IPTV services over wireless networks. Our cross-layer design uses the presentation timestamp in the RTP packet header to derive a presentation deadline for each MAC frame. In our design, the wireless Access Point (AP) uses the presentation deadline and the number of retrys to determine whether a MAC frame can be sent or not. Moreover, the MAC fragment size can adapt to the wireless channel conditions. Numerical results demonstrate that the proposed cross-layer design can avoid a waste of wireless channel resources on serving useless MAC frames which will be dropped at the receiver due to missing their presentation deadlines. In addition, the proposed cross-layer design can achieve a lower lateness loss rate and a better application layer goodput for IPTV services. View full abstract»

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  • Design of wireless sensor node for drought monitoring in vineyards

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (282 KB)  

    For the application of vineyards drought monitoring, a wireless sensor network (WSN) sensing node was designed which is suitable for setting up a WSN in vineyards. Each of the sensing nodes was composed of an ATmega128L micro-processor for data processing and controlling, SHT11 and TDR-3 sensor modules for data measurements, and a nRF905 transceiver module for data transmission and reception. In-field networking experiments were conducted in 5 different node deployments based on nodes density. The average values of packet loss rate (PLR) under different scenarios were 0.96%, 3.47%, 7.86%, 10.65%, 14.83%, respectively. Results indicated that the system can collect the temperature, humidity and soil water content, and transmit data remotely to the base station, provided with the characteristics of working stability and reliability. View full abstract»

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  • Particle swarm optimization applied to designing LDPC codes for wireless communications

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (117 KB)  

    A particle swarm optimization (PSO) method is applied to finding the optimum degree distributions of check and bit nodes of an irregular low-density parity-check (LDPC) code. This population based optimization method can efficiently reduce the number of evaluations of the computation demanding fitness function. We also show how to find the thresholds under message-passing (MP) algorithm. View full abstract»

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  • Chromatic dispersion monitor method for signals with high duty cycles

    Publication Year: 2011 , Page(s): 1 - 3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (576 KB)  

    This paper proposed a method which utilizes phase-matched FWM to effectively enhance the chromatic dispersion (CD) monitoring sensitivity and monitoring range of the signals with high duty cycles. The scheme was realized by inputting a signal and continuous probe wave simultaneously into high nonlinear fiber, and the generated idler wave, whose power carried the CD information, was followed by a filter and optical power meter. The numerical simulation showed clearly that through employing this method, the monitoring range for CSRZ and NRZ could be 8 and 6.2dB respectively. In this paper we also puted forward a peak search algorithm utilizing a TDC module to increase NRZ and CSRZ monitoring range to 800 ps/nm. View full abstract»

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  • A second-order approximation coupling model of fused biconical tapered fiber coupler

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (296 KB)  

    The paper presents a mathematical model of the fused tapered fiber coupling theory, which considers the practical position of fibers in the coupling region. Based on the theory of regular optical waveguide, attention is concentrated on the second-order approximations of the propagation constant and coupling coefficient. Experimental studies of fiber coupler are investigated in detail by fabricating couplers. It is shown that the experimental data agree with the theoretical analysis with regard to the coupling ratio. View full abstract»

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  • Survivability schemes in metro interconnected ring networks

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (502 KB)  

    In Metro interconnected ring network, each ring can be used as a protection path for the other by using the cross-connecting operation of OXCs, and hence to improve the survivability of the network. Firstly, we propose the survivability model of the metro interconnected network, and analyze the survivability schemes in detail. Then, we perform a quantitative analysis of the survivability in interconnected ring network. Next, we set up the link simulation by using Optisystem software to simulate the survivability schemes in intersection ring network. Finally, we compare the BER performance before and after the failure, and study how the EDFAs and nonlinear effects impact the performance of the network. Simulation results show that interconnected ring network can improve the survivability of MAN. In addition, the influence of cascaded EDFAs and nonlinear effects should be considered and the related parameters should be optimized while planning the metro interconnected ring network. View full abstract»

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  • Highly sensitive in-band OSNR monitors based on phase-matched four-wave mixing

    Publication Year: 2011 , Page(s): 1 - 3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (390 KB)  

    This paper presents a novel all-optical in-band optical signal-to-noise (OSNR) monitoring method based on phase-matched four-wave mixing (FWM). The monitoring ability arises from the power transfer function (PTF) giving preferential gain to clean pulses when compared to noisy pulses. By selecting the phase match condition a much higher monitoring sensitivity can be achieved at a reduced input power compared to other PTF-based methods proposed before. Numerical simulations are used to quantify the sensitivity enhancement for signals with different modulation formats. View full abstract»

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  • Research on strain sensing based on passively mode-locked fiber laser using saturable absorber

    Publication Year: 2011 , Page(s): 1 - 2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (116 KB)  

    Based on a passively mode-locked fiber laser, we proposed a new method of strain sensing. The laser cavity optical length variation, mainly caused by strain and temperature, is corresponded with the repetition frequency change which can be easily measured by spectrum analyzer. Theoretical calculation shows that the device can measured nano-strain in the optical fiber. Experimental result shows that the sensing signal is very sensitive to the environmental change. View full abstract»

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  • Optical fiber sensors based on photonics crystal fiber loop mirrors

    Publication Year: 2011 , Page(s): 1 - 7
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (476 KB)  

    We summarize various sensors based on photonic crystal fiber loop mirrors proposed by our research team, including strain sensors, temperature sensors and curvature sensors. Both of highly birefringent and lowly birefringent photonic crystal fibers (PCFs) have been inserted into fiber loop mirrors (FLMs) as the sensing elements. A temperature-insensitive strain sensor with highly birefringent PCF based FLM has been realized and it has a strain sensitivity of 0.23 pm/µε in the range of 0–30 mε. For a low-cost, a demodulation is proposed by using a distributed-feedback (DFB) laser as the light source and an optical power meter instead of an expensive OSA. Strain and curvature sensors based on FLMs are also demonstrated by using a lowly birefringent PCF, which has a strain sensitivity of 0.457 pm/µε and a curvature sensitivity of 0.337 nm/ m−1, respectively. Further, a novel and compact temperature sensor based on a FLM combined with an alcohol-filled highly birefringent PCF is proposed and experimentally demonstrated and it has a high sensitivity as high as 6.6 nm/°C. View full abstract»

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  • Optically tuning of chromatic dispersion compensators

    Publication Year: 2011 , Page(s): 1 - 3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (107 KB)  

    We present a new tuning method for chromatic dispersion compensators, which can be optically tunable. The dispersion compensators were made in Er/Yb co-doped fiber and were pumped with 980nm laser diodes. The tunable dispersion for a chirped grating and also a uniform-period grating was successfully demonstrated in the experiment. View full abstract»

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