The Experts below are selected from a list of 20889 Experts worldwide ranked by ideXlab platform
Sien Chi - One of the best experts on this subject based on the ideXlab platform.
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spectrally efficient direct detected ofdm transmission incorporating a tunable frequency gap and an iterative detection techniques
Journal of Lightwave Technology, 2009Co-Authors: Weiren Peng, Bo Zhang, Kaiming Feng, Alan E Willner, Sien ChiAbstract:We analytically and experimentally demonstrate a linearly field-modulated, direct-detected virtual single-sideband orthogonal frequency-division multiplexing (VSSB-OFDM) system that employs a tunable frequency gap and an iterative detection technique. The VSSB-OFDM that uses no frequency gap, which is referred to as the gapless VSSB-OFDM, is proposed as a spectrally efficient format. Compared with the intensity-modulated SSB-OFDM, the gapless VSSB-OFDM saves half the Electrical Bandwidth (BW), and exhibits better receiving sensitivity and more robust tolerance against fiber chromatic dispersion (CD). Furthermore, by incorporating a tunable frequency gap between the optical carrier and the OFDM data sideband, the calculating burden of the iterative detection is greatly alleviated and the system performance can be flexibly improved within moderate iterations. The width of the optimum frequency gap is found to be ${\sim} {\hbox {0.35}}$ sideband BW, which is reached by trading the levels of signal–signal beat interference and the residual image beat interference. Such a gapped VSSB-OFDM system requires fewer iterations to extract the desired data from the interfered signal and exhibits greater robustness against the carrier-to-signal-power ratio (CSPR) variation, compared with the gapless VSSB-OFDM. In this paper, the analytical model of the proposed gapped VSSB-OFDM system will be addressed. In addition, we also successfully conduct a gapped VSSB-OFDM signal transmission over 1600 km of uncompensated standard single-mode fiber (SSMF) with only ${\sim} {\hbox {3}}$ dB optical SNR (OSNR) penalty, and obtain a significant OSNR sensitivity improvement of ${\sim} {\hbox {8}}$ dB, compared with the gapless VSSB-OFDM, after such a 1600-km fiber link.
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spectrally efficient direct detected ofdm transmission employing an iterative estimation and cancellation technique
Optics Express, 2009Co-Authors: Weiren Peng, Kaiming Feng, Alan E Willner, V R Arbab, Bishara Shamee, Jengyuan Yang, L Christen, Sien ChiAbstract:We demonstrate a linearly field-modulated, direct-detected virtual SSB-OFDM (VSSB-OFDM) transmission with an RF tone placed at the edge of the signal band. By employing the iterative estimation and cancellation technique for the signal-signal beat interference (SSBI) at the receiver, our approach alleviates the need of the frequency gap, which is typically reserved for isolating the SSBI, and saves half the Electrical Bandwidth, thus being very spectrally efficient. We derive the theoretical model for the VSSB-OFDM system and detail the signal processing for the iterative approach conducted at the receiver. Possible limitations for this iterative approach are also given and discussed. We successfully transmit a 10 Gbps, 4-quadrature-amplitude-modulation (QAM) VSSB-OFDM signal through 340 km of uncompensated standard single mode fiber (SSMF) with almost no penalty. In addition, the simulated results show that the proposed scheme has an approximately 2 dB optical-signal-to-noise-ratio (OSNR) gain and has a better chromatic dispersion (CD) tolerance compared with the previous intensity-modulated SSB-OFDM system.
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experimental demonstration of 340 km ssmf transmission using a virtual single sideband ofdm signal that employs carrier suppressed and iterative detection techniques
Optical Fiber Communication Conference, 2008Co-Authors: Weiren Peng, Kaiming Feng, Alan E Willner, V R Arbab, Bishara Shamee, Jengyuan Yang, L Christen, Sien ChiAbstract:We propose and demonstrate a virtual SSB-OFDM with direct detection that uses half the Electrical Bandwidth by employing an RF tone at the edge of the signal. We transmit 10 Gbps data with a 4-QAM over 340 km of SSMF with no penalty.
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Impact of nonlinear transfer function and imperfect splitting ratio of MZM on optical up-conversion employing double sideband with carrier suppression modulation
Journal of Lightwave Technology, 2008Co-Authors: Chun Ting Lin, Sheng-peng Dai, Jason Chen, Peng-chun Peng, Sien ChiAbstract: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).
Jinwei Shi - One of the best experts on this subject based on the ideXlab platform.
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design and analysis of ultra high speed near ballistic uni traveling carrier photodiodes under a 50 omega load for high power performance
IEEE Photonics Technology Letters, 2012Co-Authors: Jinwei Shi, Fengming Kuo, John E. BowersAbstract:We demonstrate a near-ballistic uni-traveling-carrier photodiode (NBUTC-PD) with a scaled-down epi-layer structure designed for high-power performance in the sub-THz frequency regime. Compared with UTC-PDs, NBUTC-PDs offer a higher optimum bias voltage for the near-ballistic transport of electrons, which leads to improvement in the output power performance. Furthermore, a small load resistance ( <; 50nΩ), which would sacrifice the output power for minimizing the output ac voltage swing on dc bias point, is not necessary. By scaling down the collector layer thickness and active area of the NBUTC-PDs, we achieve a large optical-to-Electrical Bandwidth (250 GHz) and a high saturation current (17 mA), which is close to the theoretical maximum, under a 50-Ω load and -2-V bias.
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front end design of w band integrated photonic transmitter with wide optical to Electrical Bandwidth for wire less over fiber applications
International Microwave Symposium, 2010Co-Authors: Hsuanju Tsai, Nanwei Chen, F M Kuo, Jinwei ShiAbstract:A broadband, integrated photonic transmitter front-end is demonstrated. The front-end essentially comprises a dipole-based structure fed horn antenna and a broadband slotline to coplanar-waveguide transition. The proposed dipole-based antenna feeding structure does not call for any modifications on the waveguide and bond wires on the structure for insertion loss reduction, which is critical for an easy and low-cost transmitter implementation in the milliliter-wave regime. For experimental demonstration, the proposed front-end is integrated with a near-ballistic uni-travelling-carrier photodiode (NBUTC-PD) through flip-chip bonding for realization of a W-band integrated photonic transmitter poised for high-speed wireless data transmission. Owing to wide optical-to-Electrical Bandwidth of the NBUTC-PD integrated with the proposed front-end, the demonstrated photonic transmitter is of a high data rate up to 12.5 Gb/s and expected to find applications in the broadband wireless-over-fiber systems.
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demonstration of a dual depletion region electroabsorption modulator at 1 55 spl mu m wavelength for high speed and low driving voltage performance
IEEE Photonics Technology Letters, 2005Co-Authors: Jinwei Shi, C A Hsieh, A C Shiao, Fanhsiu Huang, Shuhan Chen, Y T Tsai, J I ChyiAbstract:We demonstrate a novel structure of electroabsorption modulator (EAM) at a 1.55-/spl mu/m wavelength: the dual-depletion-region EAM. After an n/sup +/ delta-doped layer was inserted into the thick intrinsic region (550 nm) of a tradition p-i-n modulator, the tradeoff between driving-voltage and Electrical Bandwidth performance can be released effectively. This new structure can also release the burden imposed on downscaling the width or length of high-speed EAM with low driving-voltage performance. The microwave and Electrical-to-optical measurement of this novel device with traveling-wave electrodes show very convincing results.
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high speed high responsivity and high power performance of near ballistic uni traveling carrier photodiode at 1 55 spl mu m wavelength
IEEE Photonics Technology Letters, 2005Co-Authors: Jinwei Shi, Peichin Chiu, C C HongAbstract:In this letter, we demonstrate a novel photodiode at a 1.55-/spl mu/m wavelength: the near-ballistic uni-traveling-carrier photodiode (UTC-PD). After a p/sup +/ delta-doped layer was inserted into the collector of a UTC-PD, near-ballistic transport of photogenerated electrons under high reverse bias voltage (-5 V) and a high output photocurrent (/spl sim/30 mA) was observed. The demonstrated device has been combined with an evanescently coupled optical waveguide to attain high responsivity and high saturation power performance. Extremely high responsivity (1.14 A/W), a high Electrical Bandwidth (around 40 GHz), and a high saturation current-Bandwidth product (over 1280 mA/spl middot/GHz, at 40 GHz) with high saturation radio-frequency power (over 12 dBm at 40 GHz) have been achieved simultaneously at a 1.55-/spl mu/m wavelength.
John E. Bowers - One of the best experts on this subject based on the ideXlab platform.
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design and analysis of ultra high speed near ballistic uni traveling carrier photodiodes under a 50 omega load for high power performance
IEEE Photonics Technology Letters, 2012Co-Authors: Jinwei Shi, Fengming Kuo, John E. BowersAbstract:We demonstrate a near-ballistic uni-traveling-carrier photodiode (NBUTC-PD) with a scaled-down epi-layer structure designed for high-power performance in the sub-THz frequency regime. Compared with UTC-PDs, NBUTC-PDs offer a higher optimum bias voltage for the near-ballistic transport of electrons, which leads to improvement in the output power performance. Furthermore, a small load resistance ( <; 50nΩ), which would sacrifice the output power for minimizing the output ac voltage swing on dc bias point, is not necessary. By scaling down the collector layer thickness and active area of the NBUTC-PDs, we achieve a large optical-to-Electrical Bandwidth (250 GHz) and a high saturation current (17 mA), which is close to the theoretical maximum, under a 50-Ω load and -2-V bias.
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frequency response and Bandwidth enhancement in ge si avalanche photodiodes with over 840ghz gain Bandwidth product
Optics Express, 2009Co-Authors: Wissem Sfar Zaoui, John E. Bowers, Huiwen Chen, Yimin Kang, Mike Morse, Mario J Paniccia, A Pauchard, J C CampbellAbstract:In this work we report a separate-absorption-charge-multiplication Ge/Si avalanche photodiode with an enhanced gain-Bandwidth-product of 845GHz at a wavelength of 1310nm. The corresponding gain value is 65 and the Electrical Bandwidth is 13GHz at an optical input power of −30dBm. The unconventional high gain-Bandwidth-product is investigated using device physical simulation and optical pulse response measurement. The analysis of the electric field distribution, electron and hole concentration and drift velocities in the device shows that the enhanced gain-Bandwidth-product at high bias voltages is due to a decrease of the transit time and avalanche build-up time limitation at high fields.
Weiren Peng - One of the best experts on this subject based on the ideXlab platform.
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spectrally efficient direct detected ofdm transmission incorporating a tunable frequency gap and an iterative detection techniques
Journal of Lightwave Technology, 2009Co-Authors: Weiren Peng, Bo Zhang, Kaiming Feng, Alan E Willner, Sien ChiAbstract:We analytically and experimentally demonstrate a linearly field-modulated, direct-detected virtual single-sideband orthogonal frequency-division multiplexing (VSSB-OFDM) system that employs a tunable frequency gap and an iterative detection technique. The VSSB-OFDM that uses no frequency gap, which is referred to as the gapless VSSB-OFDM, is proposed as a spectrally efficient format. Compared with the intensity-modulated SSB-OFDM, the gapless VSSB-OFDM saves half the Electrical Bandwidth (BW), and exhibits better receiving sensitivity and more robust tolerance against fiber chromatic dispersion (CD). Furthermore, by incorporating a tunable frequency gap between the optical carrier and the OFDM data sideband, the calculating burden of the iterative detection is greatly alleviated and the system performance can be flexibly improved within moderate iterations. The width of the optimum frequency gap is found to be ${\sim} {\hbox {0.35}}$ sideband BW, which is reached by trading the levels of signal–signal beat interference and the residual image beat interference. Such a gapped VSSB-OFDM system requires fewer iterations to extract the desired data from the interfered signal and exhibits greater robustness against the carrier-to-signal-power ratio (CSPR) variation, compared with the gapless VSSB-OFDM. In this paper, the analytical model of the proposed gapped VSSB-OFDM system will be addressed. In addition, we also successfully conduct a gapped VSSB-OFDM signal transmission over 1600 km of uncompensated standard single-mode fiber (SSMF) with only ${\sim} {\hbox {3}}$ dB optical SNR (OSNR) penalty, and obtain a significant OSNR sensitivity improvement of ${\sim} {\hbox {8}}$ dB, compared with the gapless VSSB-OFDM, after such a 1600-km fiber link.
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spectrally efficient direct detected ofdm transmission employing an iterative estimation and cancellation technique
Optics Express, 2009Co-Authors: Weiren Peng, Kaiming Feng, Alan E Willner, V R Arbab, Bishara Shamee, Jengyuan Yang, L Christen, Sien ChiAbstract:We demonstrate a linearly field-modulated, direct-detected virtual SSB-OFDM (VSSB-OFDM) transmission with an RF tone placed at the edge of the signal band. By employing the iterative estimation and cancellation technique for the signal-signal beat interference (SSBI) at the receiver, our approach alleviates the need of the frequency gap, which is typically reserved for isolating the SSBI, and saves half the Electrical Bandwidth, thus being very spectrally efficient. We derive the theoretical model for the VSSB-OFDM system and detail the signal processing for the iterative approach conducted at the receiver. Possible limitations for this iterative approach are also given and discussed. We successfully transmit a 10 Gbps, 4-quadrature-amplitude-modulation (QAM) VSSB-OFDM signal through 340 km of uncompensated standard single mode fiber (SSMF) with almost no penalty. In addition, the simulated results show that the proposed scheme has an approximately 2 dB optical-signal-to-noise-ratio (OSNR) gain and has a better chromatic dispersion (CD) tolerance compared with the previous intensity-modulated SSB-OFDM system.
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experimental demonstration of 340 km ssmf transmission using a virtual single sideband ofdm signal that employs carrier suppressed and iterative detection techniques
Optical Fiber Communication Conference, 2008Co-Authors: Weiren Peng, Kaiming Feng, Alan E Willner, V R Arbab, Bishara Shamee, Jengyuan Yang, L Christen, Sien ChiAbstract:We propose and demonstrate a virtual SSB-OFDM with direct detection that uses half the Electrical Bandwidth by employing an RF tone at the edge of the signal. We transmit 10 Gbps data with a 4-QAM over 340 km of SSMF with no penalty.
C C Hong - One of the best experts on this subject based on the ideXlab platform.
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high speed high responsivity and high power performance of near ballistic uni traveling carrier photodiode at 1 55 spl mu m wavelength
IEEE Photonics Technology Letters, 2005Co-Authors: Jinwei Shi, Peichin Chiu, C C HongAbstract:In this letter, we demonstrate a novel photodiode at a 1.55-/spl mu/m wavelength: the near-ballistic uni-traveling-carrier photodiode (UTC-PD). After a p/sup +/ delta-doped layer was inserted into the collector of a UTC-PD, near-ballistic transport of photogenerated electrons under high reverse bias voltage (-5 V) and a high output photocurrent (/spl sim/30 mA) was observed. The demonstrated device has been combined with an evanescently coupled optical waveguide to attain high responsivity and high saturation power performance. Extremely high responsivity (1.14 A/W), a high Electrical Bandwidth (around 40 GHz), and a high saturation current-Bandwidth product (over 1280 mA/spl middot/GHz, at 40 GHz) with high saturation radio-frequency power (over 12 dBm at 40 GHz) have been achieved simultaneously at a 1.55-/spl mu/m wavelength.