Browsing by Author "Peng, Wei-Ren"

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A star-ring-bus architecture for WDM fiber-wireless system
(2006-01-01)
Chiou, Hung-Yu
;
Peng, Peng-Chun
;
Feng, Kai-Ming
;
Peng, Wei-Ren
;
Chen, JyeHong
A self-healing star-ring-bus architecture for high-capacity WDM fiber-wireless system is proposed and verified experimentally. This architecture can provide reliable, flexible, and robust characteristics for large radio terminals. (C) 2006 Optical Society of America.
Analysis of Laser Phase Noise Effect in Direct-Detection Optical OFDM Transmission
(2010-09-01)
Peng, Wei-Ren
;
光電工程學系
;
Department of Photonics
In this paper, we characterize the impact of laser phase noise (PN) in direct-detection optical OFDM (DDO-OFDM) and identify its many differences from those in coherent optical OFDM (CO-OFDM). The analytical models for the diverse PN effects, including power degradation, phase rotation term (PRT), and inter-carrier interference (ICI), are given in terms of critical system parameters with or without the small PN assumption. In particular, the analytical upper-bound of the ICI power with a simple form is also provided. We also present a bit error rate (BER) estimation approach which is proven to be reliable for an optical signal-to-noise-ratio (OSNR) penalty lower than 2 dB. In addition, the PN tolerances, in terms of OSNR penalty, are also numerically analyzed and discussed with different QAM formats, data rates, laser linewdiths, and subcarrier numbers.
Bit Error Rate Calculation for a Single Sideband OFDM Signal with Direct Detection Optically Pre-amplified Receivers
(2008)
Peng, Wei-Ren
;
Feng, Kai-Ming
;
Chi, Sien
;
Willner, Alan E.
;
光電工程學系
We provide a fast and accurate BER calculation for a SSB-OFDM signal by considering the SNR of each subcarrier separately. The numerical results show that our scheme can accurately evaluate the BER for different QAM formats even under a strong optical filtering. (C) 2008 Optical Society of America
Compensation for I/Q Imbalances and Bias Deviation of the Mach-Zehnder Modulators in Direct-Detected Optical OFDM Systems
(2009-01-01)
Peng, Wei-Ren
;
Zhang, Bo
;
Wu, Xiaoxia
;
Feng, Kai-Ming
;
Willner, Alan E.
We demonstrate an equalization technique to simultaneously compensate for the fiber chromatic dispersion and the distortions induced by the in-phase/quadrature-phase (I/Q) imbalances and bias deviation in the Mach-Zehnder modulators (MZMs). With this technique, the requirement for the monitoring circuits at the transmitter could be relaxed or even eliminated, and thus simplifies the system design and reduces the system cost. The system exhibits a good performance with our proposal over a broad range of imbalances and bias deviation in the MZM. With deliberately introducing I/Q imbalances and bias deviation, we have observed a 2- and 4-dB optical signal-to-noise ratio improvement, for the back-to-back and 800 km of uncompensated standard single-mode fiber transmission, respectively, with our proposed scheme.
DPSK-Labeled Direct-Detected Optical OFDM Transmission
(2009)
Peng, Wei-Ren
;
Feng, Kai-Ming
;
Chi, Sien
;
光電工程學系
;
Department of Photonics
We propose the generation, detection, and label swapping methods for DPSK-labelled OFDM transmission. Without increasing the signal bandwidth, we show the attached label has almost no influence on the superior performance of OFDM payload. (C) 2009 Optical Society of America
Estimation of the Bit Error Rate for Direct-Detected OFDM Signals With Optically Preamplified Receivers
(2009-05-15)
Peng, Wei-Ren
;
Feng, Kai-Ming
;
Willner, Alan E.
;
Chi, Sien
;
光電工程學系
In this paper, we provide a numerical bit error rate (BER) estimation approach for direct-detected orthogonal frequency division multiplexing (OFDM) signals in the presence of optical preamplified receivers. The individual BER of each subcarrier is first computed by considering their electrical signal-to-noise ratio (SNR), and then the ensemble BER is derived simply by taking the average of all the subcarriers' BERs. The calculated BER is verified by the conventional error-counting approach with high precision and is still accurate with higher quadratic-amplitude modulation (QAM) formats, even under the influences of the optical filtering and polarization mode dispersion (PMD) effects. Based on our simulation approach, the required extra power budget for 16- and 64-QAM relative to 4-QAM format are found to be similar to 3.8 and 8.2 dB, respectively, at a BER of 10(-9) Furthermore, we use this approach to compare the receiving sensitivities and PMD tolerances for the previous proposed gapped and interleaved radio-frequency (RF)-tone-assisted OFDM systems. The results show that the gapped OFDM has a better sensitivity while the interleaved OFDM has a more PMD-tolerable capability.
Evaluation of the inherent ripple effects on the performance of an optical DQPSK signal generated by using only one MZM
(2006)
Peng, Wei-Ren
;
Chen, Jason (Jyehong)
;
Tsai, Shen-You
;
Tsao, Cheng
;
Chi, Sien
We analytically computed the optical spectra and numerically evaluated the ripple impacts on the performance of an optical DQPSK signal generated by only one MZM. We confirmed the necessity of a pulse carver to this kind of signal. The tolerances to the timing mismatch between the data and the pulse carver were analyzed among different duty-cycles. The conventional DQPSK signal generated by two parallel DPSK modulators were also analyzed for comparisons. We also provided some experimental results to demonstrate the possibility of the one-MZM scheme and the necessity of a pulse carver in terms of the clearly opened demodulated eyes.
Experimental Demonstration of 1600 km SSMF Transmission of a Generalized Direct Detection Optical Virtual SSB-OFDM System
(2008-01-01)
Peng, Wei-Ren
;
Zhang, Bo
;
Wu, XiaoXia
;
Feng, Kai-Ming
;
Willner, Alan E.
We experimentally demonstrate a generalized VSSB-OFDM format that judiciously determines the frequency gap between an inserted RF tone and the signal. The proposed scheme for 10 Gbps exhibits similar to 3 dB penalty after 1600 km SSMF transmission, and has an 8 dB improvement over the regular VSSB-OFDM.
Experimental demonstration of 340 km SSMF transmission using a virtual single sideband OFDM signal that employs carrier suppressed and iterative detection techniques
(2008-01-01)
Peng, Wei-Ren
;
Wu, Xiaoxia
;
Arbab, Vahid R.
;
Shamee, Bishara
;
Yang, Jeng-Yuan
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 kin of SSMF with no penalty. (C) 2008 Optical Society of America.
Experimental demonstration of a coherently modulated and directly detected optical OFDM system using an RF-tone insertion
(2008-01-01)
Peng, Wei-Ren
;
Wu, Xiaoxia
;
Arbab, Vahid R.
;
Shamee, Bishara
;
Christen, Louis C.
We experimentally demonstrate an RF-tone assisted OFDM transmission. Our system has a 5-dB better sensitivity compared to the conventional baseband SSB-OFDM and exhibits a negligible penalty transmission after 260 km of SSMF. (C) 2008 Optical Society of America.
Hybrid Optical Access Network Integrating Baseband and Radio Signals Transmitted on a Single Wavelength
(2007)
Lin, Chun-Ting
;
Peng, Peng-Chun
;
Chen, Jason (Jyehong)
;
Peng, Cheng-Feng
;
Peng, Wei-Ren
We propose a hybrid optical access network integrating FTTH and RoF systems sharing a single distributed infrastructure. After transmission over 50km optical fiber, power penalties of baseband and RF signals are less than 0.2dB. (C) 2007 Optical Society of America
Hybrid optical access network integrating fiber-to-the-home and radio-over-fiber systems
(2007-03-01)
Lin, Chun-Ting
;
Chen, Jason (Jyehong)
;
Peng, Peng-Chun
;
Peng, Cheng-Feng
;
Peng, Wei-Ren
Hybrid optical access networks, integrating fiber-to-the-home (FTTH) and radio-over-fiber (RoF) systems that share a single distributed infrastructure, are promising for future multiservice access networks. The primary concern is to enable RoF and FTTH systems to transmit both radio-frequency (RF) and baseband (BB) signals on a single wavelength over a single fiber. This study experimentally demonstrates simultaneous generation and transmission of a wired-line BB signal and a wireless RF signal on a single wavelength, using one external modulator. The hybrid signals transmitted over standard single-mode fiber (SSMF) do not suffer from periodic performance fading due to fiber dispersion. Following transmission over 50-km SSMF, the power penalties of both RF and BB signals are less than 0.2 dB.
Joint CD and PMD Compensation for Direct-Detected Optical OFDM Using Polarization-Time Coding Approach
(2009)
Peng, Wei-Ren
;
Feng, Kai-Ming
;
Chi, Sien
;
光電工程學系
;
Department of Photonics
We demonstrate a polarization-time coding method for direct-detected OFDM, which provides the signal with immunity against both fibre CD and PMD effects. Further dynamic PTC method is introduced for trading the PMD tolerance with receiving sensitivity.
Joint compensation of CD and PMD in direct-detected OFDM transmission using polarization-time coding
(2010-02-01)
Peng, Wei-Ren
;
Feng, Kai-Ming
;
Chi, Sien
;
光電工程學系
;
Department of Photonics
We propose and demonstrate a polarization-time coding (PTC) method which can effectively compensate both the CD and first order PMD in direct-detected OFDM transmission. Compared with the previous methods, the proposed PTC not only alleviates the need for the complex dynamic polarization controller but also exhibits superior transparencies to both the OFDM format and transmission data rate. For the proposed PTC method, we have analytically derived the transmission model with CD and first order PMD, and theoretically prove the PTC indeed can jointly compensate both CD and PMD. The numerical results show that, with the PTC method, both the previously proposed gapped and interleaved OFDM formats behave virtually immune to both CD and PMD with a price of 3-dB OSNR penalty in back-to-back (BtB). Aimed to mitigate this BtB 3-dB penalty, further partial PTC approach is proposed for trading the PMD tolerance with the BtB OSNR sensitivity. The interleaved OFDM system is found to gain profits in terms of lower sensitivity with the partial coding. (C) 2010 Optical Society of America
On the Phase Noise Impact in Direct-Detection Optical OFDM Transmission
(2010-05-01)
Peng, Wei-Ren
;
(Jyehong) Chen, Jason
;
Chi, Sien
;
光電工程學系
;
Department of Photonics
In this letter, we characterize the impact of laser phase noise (PN) in direct-detection optical orthogonal frequency-division multiplexing (OFDM) and emphasize its several differences from those in coherent optical OFDM. We also analyze the system performance in the presence of PN for various quadrature-amplitude-modulation formats and provide the bit-error-rate estimation method which can yield reliable results when the PN-induced optical signal-to-noise ratio penalty is lower than similar to 2 dB.
Quantum limit of optimum four-level ASK signals with direct detection optically preamplified receivers
(2007-05-28)
Peng, Wei-Ren
;
Chi, Sien
;
光電工程學系
;
Department of Photonics
We analytically obtain the exact fundamental limit of 4- level amplitude shifted keying formats (4ASK) with direct detection optically preamplified receivers. The optimum multilevel spacing and the corresponding decision thresholds, which depend both on the signal to noise ratio and optical bandwidth, are obtained numerically considering the Chis-quared distribution of each level. The quantum limit under the optimum level spacing is 127.5 photons/bit, which is about 0.2 dB smaller than the results by the Gaussian approximation. Over a broad range of the signal to noise ratio and the optical bandwidth, we have found that not only the bit error rate but also the optimum level spacing are well predicted by Gaussian method, although the three decision thresholds are all underestimated. (C) 2007 Optical Society of America.
Reliable architecture for high-capacity fiber-radio systems
(2007-07-01)
Peng, Peng-Chun
;
Feng, Kai-Ming
;
Chiou, Hung-Yu
;
Peng, Wei-Ren
;
Chen, Jason (Jyehong)
In this paper, we present a reliable architecture for high-capacity fiber-radio system and demonstrate its feasibility. The main trunk of the proposed architecture is a star network with branches comprising a series of concatenated ring subnets. The conventional drawback, the lack of reliability, of star networks is overcome by the ring subnets with a self-healing function based on optical switches. To compensate the extra loss of the system, we adopt compact erbium-doped waveguide amplifiers to construct our proposed architecture. The architecture can provide highly reliable, flexible, and robust performance for fiber-radio systems. (c) 2007 Elsevier Inc. All rights reserved.
Sensitivity Bound for Optically-Preamplified Direct-Detected OFDM Systems Using Spectrally Matched Filters
(2009)
Peng, Wei-Ren
;
Feng, Kai-Ming
;
Willner, Alan E.
;
Chi, Sien
;
光電工程學系
We investigate the sensitivity bound, in terms of OSNR, for direct-detected OFDM systems in presence of optically-preamplified receivers, and show that OSNR requirement for DD-OFDM could theoretically reach that of CO-OFDM using the spectrally matched filters. (C) 2009 Optical Society of America
Simultaneous baseband and RF signal generation using only one single-electrode MZM based on double-sideband with optical carrier suppression
(2006)
Lin, Chun-Ting
;
Peng, Wei-Ren
;
Peng, Peng-Chun
;
Peng, Cheng-Feng
;
Chiang, Chun-Chen
We propose and experimentally demonstrate a simple simultaneous generation of baseband and RF signal based on double-sideband with optical carrier suppression (DSBCS). The relation between the RF driving level (VP-P/2V pi) for dual-electrode MZM and the receiver sensitivity are studied. Based on the optimal RF driving level of 0.43, only one single-electrode MZM is needed to generate the microwave using DSBCS scheme. After the microwave based on DSBCS scheme using only one single-electrode MZM is transmitted over 100km of SSMF, no penalty for the baseband and down-converted signals of the receiver sensitivity is observed.
Simultaneous generation of baseband and radio signals using only one single-electrode Mach-Zehnder modulator with enhanced linearity
(2006-11-01)
Lin, Chun-Ting
;
Peng, Wei-Ren
;
Peng, Peng-Chun
;
Chen, Jason (Jyehong)
;
Peng, Cheng-Feng
We experimentally demonstrate a simultaneous generation of baseband (BB) and RF signals, using only one single-electrode Mach-Zehnder modulator (SD-MZM) based on double-sideband with optical carrier suppression (DSBCS) scheme. With optimal modulation index (MI = Vp-p/2V(pi)) equal to 0.43 for driving MZM, the receiver sensitivity of the RF signal can have 1-dB improvement. Based on this result, only one SD-MZM is needed to generate optical microwaves using DSBCS scheme, thus eliminating the requirement of a high-cost dual-electrode MZM without degrading the signal performance. Following 75-km standard single-mode fiber, the power penalties of both BB and RF signals are less than 0.3 dB.