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Ampalavanapillai Nirmalathas - One of the best experts on this subject based on the ideXlab platform.

  • capacity analysis for wdm fiber radio backbones with star tree and ring architecture incorporating wavelength interleaving
    Journal of Lightwave Technology, 2003
    Co-Authors: Ampalavanapillai Nirmalathas, D Novak, R Waterhouse
    Abstract:

    We present a model based on link budget calculations to investigate the capacity of a wavelength-division-multiplexed (WDM) fiber-radio backbone incorporating a wavelength-interleaving technique. The wavelength-interleaving technique improves the Optical Spectral Efficiency of the millimeter-wave fiber-radio systems incorporating Optical single sideband with carrier modulation. In this paper, we investigate the capacity limitations of WDM fiber-radio backbones incorporating both wavelength interleaving and Optical single sideband with carrier modulation for star-tree and ring architecture. The analysis provides an estimation of the overall system capacity and an insight into the network layout and performance limitations.

  • Dispersion tolerant novel base station Optical interface for future WDM fibre-radio systems
    2003
    Co-Authors: Masuduzzaman Bakaul, Ampalavanapillai Nirmalathas, Christina Lim
    Abstract:

    To realise simple, compact and low-cost base stations (BSs) for millimetrewave fibre-radio systems, we have proposed and demonstrated a novel BS Optical interface that supports wavelength interleaving to improve the Optical Spectral Efficiency as well as wavelength re-use to facilitate upstream transmission. The proposed Optical interface is realised by the use of a multi-port Optical circulator (OC) in conjunction with multi-notch fibre Bragg grating (FBG) filters.

  • A WDM fiber-radio system with improved Optical Spectral Efficiency incorporating remote LO delivery and novel FBG Optical filtering
    OFC 2003 Optical Fiber Communications Conference 2003., 2003
    Co-Authors: C. Marra, Christina Lim, Ampalavanapillai Nirmalathas, Dalma Novak, M. Attygalle, Leon Poladian, Wayne S. T. Rowe, T. Wang, L. Reekie, J.a. Besley
    Abstract:

    A novel WDM fiber radio system with improved Spectral Efficiency, incorporating remote LO delivery and novel FBG Optical filtering techniques is demonstrated. All channels within a 25 GHz band are successfully recovered with minimal degradation.

  • wavelength interleaved oadms incorporating optimized multiple phase shifted fbgs for fiber radio systems
    Journal of Lightwave Technology, 2003
    Co-Authors: C. Marra, Ampalavanapillai Nirmalathas, D Novak, L. Reekie, J.a. Besley, C Weeks, N J Baker
    Abstract:

    We demonstrate that a single fiber Bragg grating (FBG)-based Optical add-drop multiplexer can be used to improve the Optical Spectral Efficiency in a mm-wave WDM-fiber wireless network. The technique employs wavelength interleaving in conjunction with Optical single-sideband modulation, together with a single multiphase-shifted fiber Bragg grating. Wavelength Optical add-drop features are also demonstrated using the grating, and our results show the performance of the novel grating in terms of channel isolation and add-drop functionality. We perform simulations to optimize placement of the phase shifts when an apodization profile is applied to the grating, in an attempt to minimize in-band and out-of-band transmission-amplitude ripples. Experiments are performed using cascade configurations both with the apodized gratings with optimal phase-shift positions and with the original unoptimized gratings. The experimental results demonstrate how these novel gratings can be used in fiber-radio networks incorporating multiple Optical add-drop multiplexers.

  • technique for increasing Optical Spectral Efficiency in millimetre wave wdm fibre radio
    Electronics Letters, 2001
    Co-Authors: Christina Lim, Ampalavanapillai Nirmalathas, Dalma Novak, Rodney S. Tucker, Rod Waterhouse
    Abstract:

    A novel technique for increasing the Spectral Efficiency of millimetre-wave fibre-radio systems by employing wavelength interleaving in conjunction with Optical single sideband modulation, is proposed and demonstrated. The technique has been demonstrated experimentally by employing a wavelength interleaved Optical add-drop multiplexer and transmission of a 155 Mbit/s BPSK signal at 36 GHz over 20 km of fibre.

William Shieh - One of the best experts on this subject based on the ideXlab platform.

  • Optical Field Recovery in Stokes Space
    Journal of Lightwave Technology, 2019
    Co-Authors: Di Che, Chuanbowen Sun, William Shieh
    Abstract:

    Coherent detection empowers Optical receivers the capability of recovering the Optical field propagating through the fiber. Field recovery not only increases the degree of freedom for Optical modulations, but also enables the digital compensation of fiber dispersion that avoids the sophisticated Optical dispersion management. Compared with coherent detection, direct detection (DD) owns a natural advantage—the simplicity, but lacks the capability of field recovery. To increase the modulation dimension for DD, the recent development of Stokes vector receiver takes the advantage of polarization diversity and extends the modulation dimension up to three-dimension with reference to the four-dimensional coherent detection (i.e., dual-polarization intensity and phase). However, a Stokes vector receiver is not inherently capable of field recovery because the second-order signal representation in Stokes space nonlinearizes the first-order linear field information, making it infeasible to digitally compensate the chromatic dispersion. In this paper, we provide a comprehensive review of Stokes-space field recovery (SSFR) that completely or partially recovers the Optical field by DD. We analyze the degree of freedom for a variety of Stokes-space modulations compatible with SSFR, and reveal their tradeoff between Optical Spectral Efficiency (that determines fiber capacity) and electrical Spectral Efficiency (that determines transceiver cost per bit). We review the Stokes-space polarization recovery methods and generalize a novel concept as analog polarization identification to simplify the DSP of SSFR. Furthermore, we compare the OSNR sensitivity among various common direct detection schemes to provide reliable predictions of their transmission performance. With its high Spectral Efficiency and capability of digital dispersion compensation, SSFR is very promising for future high-capacity short-reach applications over single- or multispan fiber transmission.

  • Rejuvenating direct modulation and direct detection for modern Optical communications
    Optics Communications, 2018
    Co-Authors: Di Che, Xi Chen, William Shieh
    Abstract:

    Abstract High-speed transoceanic Optical fiber transmission using direct modulation (DM) and direct detection (DD) was one of the most stirring breakthroughs for telecommunication in 1990s, which drove the internet as a global phenomenon. However, the later evolution of Optical coherent communications in 2000s gradually took over the long-haul applications, due to its superior Optical Spectral Efficiency. Nowadays, DM–DD systems are dominant mainly in cost- and power-sensitive short-reach applications, because of its natural characteristics—the simplicity. This paper reviews the recent advances of DM–DD transceivers from both hardware and signal processing perspectives. It introduces a variety of modified DM and/or DD systems for 3 application scenarios: very-short-reach interconnect with little fiber channel impact; single or a few spans of fiber transmission up to several hundred km; and distance beyond the 2nd scenario. Besides the DM–DD and multi-dimension DM–DD with polarization diversity, this paper focuses on how to rejuvenate traditional DM and DD technologies in order to bridge the transmission application gap between DM-DD and coherent transceivers, using technologies such as dispersion compensation, signal field recovery from the intensity-only DD receiver, and complex direct modulation with coherent detection. More than 30 years since the birth, DM and DD still hold indispensable roles in modern Optical communications.

  • experimental demonstration and numerical simulation of 107 gb s high Spectral Efficiency coherent Optical ofdm
    Journal of Lightwave Technology, 2009
    Co-Authors: Qi Yang, Yan Tang, William Shieh
    Abstract:

    Orthogonal frequency-division multiplexing (OFDM) is a multicarrier modulation format in which the data are transmitted with a set of orthogonal subcarriers. Recently, this modulation format has been actively explored in the field of Optical communications to take advantages of its high Spectral Efficiency and resilience to chromatic and polarization dispersion. However, to realize the Optical OFDM at 100 Gb/s and beyond requires extremely high electronic bandwidth for the electronic signal processing elements. In this paper, we investigate orthogonal-band-multiplexed OFDM (OBM-OFDM) as a suitable modulation and multiplexing scheme for achieving bandwidth scalable and Spectral efficient long-haul transmission systems. The OBM-OFDM signal can be implemented in either RF domain, or Optical domain, or a combination of both domains. Using the scheme of OBM-OFDM, we show the successful transmission of 107 Gb/s data rate over 1000-km standard single-mode fiber (SSMF) without Optical dispersion compensation and without Raman amplification. The demonstrated OBM-OFDM system is realized in Optical domain which employs 2times2 MIMO-OFDM signal processing and achieves high Optical Spectral Efficiency of 3.3 bit/s/Hz using 4-QAM encoding. Additionally, we perform numerical simulation of 107-Gb/s CO-OFDM transmission for both single-channel and wavelength-division-multiplexed (WDM) systems. We find that the Q -factor of OBM-OFDM measured using uniform filling of OFDM subbands is in fact more conservative, in particular, is 1.2 dB and 0.4 dB lower than using random filling for single-channel and WDM systems, respectively.

  • experimental demonstration and numerical simulation of 107 gb s high Spectral Efficiency coherent Optical ofdm
    OFC NFOEC 2008, 2009
    Co-Authors: Qi Yang, Yan Tang, William Shieh
    Abstract:

    Orthogonal frequency-division multiplexing (OFDM) is a multicarrier modulation format in which the data are transmitted with a set of orthogonal subcarriers. Recently, this modulation format has been actively explored in the field of Optical communications to take advantages of its high Spectral Efficiency and resilience to chromatic and polarization dispersion. However, to realize the Optical OFDM at 100 Gb/s and beyond requires extremely high electronic bandwidth for the electronic signal processing elements. In this paper, we investigate orthogonal-band-multiplexed OFDM (OBM-OFDM) as a suitable modulation and multiplexing scheme for achieving bandwidth scalable and Spectral efficient long-haul transmission systems. The OBM-OFDM signal can be implemented in either RF domain, or Optical domain, or a combination of both domains. Using the scheme of OBM-OFDM, we show the successful transmission of 107 Gb/s data rate over 1000-km standard single-mode fiber (SSMF) without Optical dispersion compensation and without Raman amplification. The demonstrated OBM-OFDM system is realized in Optical domain which employs 2 × 2 MIMO-OFDM signal processing and achieves high Optical Spectral Efficiency of 3.3 bit/s/Hz using 4-QAM encoding. Additionally, we perform numerical simulation of 107-Gb/s CO-OFDM transmission for both single-channel and wavelength-division-multiplexed (WDM) systems. We find that the Q-factor of OBM-OFDM measured using uniform filling of OFDM subbands is in fact more conservative, in particular, is 1.2 dB and 0.4 dB lower than using random filling for single-channel and WDM systems, respectively.

R Waterhouse - One of the best experts on this subject based on the ideXlab platform.

  • capacity analysis for wdm fiber radio backbones with star tree and ring architecture incorporating wavelength interleaving
    Journal of Lightwave Technology, 2003
    Co-Authors: Ampalavanapillai Nirmalathas, D Novak, R Waterhouse
    Abstract:

    We present a model based on link budget calculations to investigate the capacity of a wavelength-division-multiplexed (WDM) fiber-radio backbone incorporating a wavelength-interleaving technique. The wavelength-interleaving technique improves the Optical Spectral Efficiency of the millimeter-wave fiber-radio systems incorporating Optical single sideband with carrier modulation. In this paper, we investigate the capacity limitations of WDM fiber-radio backbones incorporating both wavelength interleaving and Optical single sideband with carrier modulation for star-tree and ring architecture. The analysis provides an estimation of the overall system capacity and an insight into the network layout and performance limitations.

D Novak - One of the best experts on this subject based on the ideXlab platform.

  • capacity analysis for wdm fiber radio backbones with star tree and ring architecture incorporating wavelength interleaving
    Journal of Lightwave Technology, 2003
    Co-Authors: Ampalavanapillai Nirmalathas, D Novak, R Waterhouse
    Abstract:

    We present a model based on link budget calculations to investigate the capacity of a wavelength-division-multiplexed (WDM) fiber-radio backbone incorporating a wavelength-interleaving technique. The wavelength-interleaving technique improves the Optical Spectral Efficiency of the millimeter-wave fiber-radio systems incorporating Optical single sideband with carrier modulation. In this paper, we investigate the capacity limitations of WDM fiber-radio backbones incorporating both wavelength interleaving and Optical single sideband with carrier modulation for star-tree and ring architecture. The analysis provides an estimation of the overall system capacity and an insight into the network layout and performance limitations.

  • wavelength interleaved oadms incorporating optimized multiple phase shifted fbgs for fiber radio systems
    Journal of Lightwave Technology, 2003
    Co-Authors: C. Marra, Ampalavanapillai Nirmalathas, D Novak, L. Reekie, J.a. Besley, C Weeks, N J Baker
    Abstract:

    We demonstrate that a single fiber Bragg grating (FBG)-based Optical add-drop multiplexer can be used to improve the Optical Spectral Efficiency in a mm-wave WDM-fiber wireless network. The technique employs wavelength interleaving in conjunction with Optical single-sideband modulation, together with a single multiphase-shifted fiber Bragg grating. Wavelength Optical add-drop features are also demonstrated using the grating, and our results show the performance of the novel grating in terms of channel isolation and add-drop functionality. We perform simulations to optimize placement of the phase shifts when an apodization profile is applied to the grating, in an attempt to minimize in-band and out-of-band transmission-amplitude ripples. Experiments are performed using cascade configurations both with the apodized gratings with optimal phase-shift positions and with the original unoptimized gratings. The experimental results demonstrate how these novel gratings can be used in fiber-radio networks incorporating multiple Optical add-drop multiplexers.

Christina Lim - One of the best experts on this subject based on the ideXlab platform.

  • Dispersion tolerant novel base station Optical interface for future WDM fibre-radio systems
    2003
    Co-Authors: Masuduzzaman Bakaul, Ampalavanapillai Nirmalathas, Christina Lim
    Abstract:

    To realise simple, compact and low-cost base stations (BSs) for millimetrewave fibre-radio systems, we have proposed and demonstrated a novel BS Optical interface that supports wavelength interleaving to improve the Optical Spectral Efficiency as well as wavelength re-use to facilitate upstream transmission. The proposed Optical interface is realised by the use of a multi-port Optical circulator (OC) in conjunction with multi-notch fibre Bragg grating (FBG) filters.

  • A WDM fiber-radio system with improved Optical Spectral Efficiency incorporating remote LO delivery and novel FBG Optical filtering
    OFC 2003 Optical Fiber Communications Conference 2003., 2003
    Co-Authors: C. Marra, Christina Lim, Ampalavanapillai Nirmalathas, Dalma Novak, M. Attygalle, Leon Poladian, Wayne S. T. Rowe, T. Wang, L. Reekie, J.a. Besley
    Abstract:

    A novel WDM fiber radio system with improved Spectral Efficiency, incorporating remote LO delivery and novel FBG Optical filtering techniques is demonstrated. All channels within a 25 GHz band are successfully recovered with minimal degradation.

  • technique for increasing Optical Spectral Efficiency in millimetre wave wdm fibre radio
    Electronics Letters, 2001
    Co-Authors: Christina Lim, Ampalavanapillai Nirmalathas, Dalma Novak, Rodney S. Tucker, Rod Waterhouse
    Abstract:

    A novel technique for increasing the Spectral Efficiency of millimetre-wave fibre-radio systems by employing wavelength interleaving in conjunction with Optical single sideband modulation, is proposed and demonstrated. The technique has been demonstrated experimentally by employing a wavelength interleaved Optical add-drop multiplexer and transmission of a 155 Mbit/s BPSK signal at 36 GHz over 20 km of fibre.

  • Wavelength-interleaving technique to improve Optical Spectral Efficiency in millimeter-wave WDM fiber-radio
    LEOS 2001. 14th Annual Meeting of the IEEE Lasers and Electro-Optics Society (Cat. No.01CH37242), 1
    Co-Authors: Christina Lim, Ampalavanapillai Nirmalathas, Dalma Novak, Rodney S. Tucker, Rod Waterhouse
    Abstract:

    In this paper we present a novel wavelength-interleaving scheme to increase the Optical Spectral Efficiency in mm-wave WDM fiber-radio systems and demonstrate the feasibility of the proposed scheme via experiment and simulation. The technique employs wavelength interleaving in conjunction with OSSB+C modulation. A wavelength-interleaved Optical add-drop multiplexer using fiber gratings and an Optical circulator was realized to implement the technique, the feasibility of which was demonstrated via three interleaved WDM channels each transporting a 155 Mb/s BPSK signal at 36 GHz over a 20 km fiber link. Capacity analysis shows that the wavelength-interleaving technique increases the maximum number of channels by almost 75% after taking into account overall system performance and device limitation.

  • Capacity analysis for a WDM fiber-radio backbone incorporating wavelength-interleaving
    Optical Fiber Communication Conference and Exhibit, 1
    Co-Authors: Christina Lim, Ampalavanapillai Nirmalathas, Dalma Novak, Rod Waterhouse
    Abstract:

    We have investigated network capacity limitations for star-tree WDM mm-wave fiber-radio systems incorporating wavelength-interleaving technique to increase Optical Spectral Efficiency. A model was developed based on link budget calculations to provide estimations of the network capacity which can also be utilized to find the optimum network architecture in conjunction with other factors such as cost. It was found that a completely passive feeder network offers simplicity however is limited by a maximum network reach of 9 km. A pre-amplification arrangement enables a centralized control architecture, however amplifier saturation effects limit the System capacity to 100 channels with a network reach of 50 km. Incorporating an amplified RN architecture (post-amplification) significantly increases the overall capacity however increased cost and network management complexity trade-offs must be also take into account.