Browsing by Author "Yeh, C. H."

Now showing 1 - 20 of 141

10 Gb/s optical carrier distributed network with W-band (0.1 THz) short-reach wireless communication system
(2012-10-01)
Chow, C. W.
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Yang, L. G.
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Yeh, C. H.
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Huang, C. B.
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Shi, J. W.
Millimeter-wave (mm-wave) operated in W-band (75 GHz-0.11 THz) is of particular interests, since this frequency band can carry signals at much higher data rates. We demonstrate a 10 Gb/s optical carrier-distributed network with the wireless communication system. The mm-wave signal at carrier frequency of 0.1 THz is generated by a high speed near-ballistic uni-traveling carrier photodiode (NBUTC-PD) based transmitter (Tx), which is optically excited by optical short pulses. The optical pulse source is produced from a self-developed photonic mm-wave waveform generator (PMWG), which allows spectral line-by-line pulse shaping. Hence these optical pulses have high tolerance to fiber chromatic dispersion. The W-band 10 Gb/s wireless data is transmitted and received via a pair of horn antennas. The received 10 Gb/s data is envelope-detected and then used to drive an optical modulator at the remote antenna unit (RAU) to produce the upstream signal sending back to the central office (CO). 20 km single mode fiber (SMF) error free transmission is achieved. Analysis about the optimum repetition rate of the optical pulse source and the transmission performance of the upstream signal are also performed and discussed. (C) 2012 Elsevier B.V. All rights reserved.
10 Gb/s TDM passive optical networks using four wavelengths multiplexed channels
(2009-07-01)
Wang, C. H.
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Shih, F. Y.
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Yeh, C. H.
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Chow, C. W.
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Chi, S.
We propose a new architecture for 10 Gb/s upstream traffic in TDM-PON using externally injection-locked Fabry-Perot laser diodes (FP-LDs) in each optical network unit (ONU). Four directly modulated 2.5 Gb/s FP-LDs were injection-locked by continuous wave (CW) carriers distributed from the optical line terminal (OLT). Hence, a total of 10 Gb/s upstream traffic can be achieved. Experimental results show negligible power penalty at a transmission of 25 km standard single mode fiber (SMF) without dispersion compensation. The performance of the injection-locked FP-LD is also studied. (C) 2009 Elsevier B.V. All rights reserved.
10 Gb/s Uplink Traffic Transmitter Using External Optical Injection for TDM Passive Optical Networks
(2009)
Wang, C. H.
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Shih, F. Y.
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Yeh, C. H.
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Chow, C. W.
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Chi, S.
We propose and demonstrate an upgrade solution for 10-Gb/s TDM-PON using four directly-modulated 2.5-Gb/s FP-LDs in each ONU. The performance of the proposed scheme is analyzed, showing its feasibility for the next-generation 10-Gb/s networks. (C) 2009 Optical Society of America
10-Gb/s Upstream TDM-PON Based on Four WDM Signals with OFDM-QAM Remodulation
(2009)
Yeh, C. H.
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Chow, C. W.
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光電工程學系
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Department of Photonics
We investigate an extend reach TDM-PON using four wavelength-multiplexed channels to achieve 16 Gb/s OFDM-QAM downlink and 10 Gb/s OOK remodulation uplink traffics.
100 GHz ultra-wideband (UWB) fiber-to-the-antenna (FTTA) system for in-building and in-home networks
(2010-01-18)
Chow, C. W.
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Kuo, F. M.
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Shi, J. W.
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Yeh, C. H.
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Wu, Y. F.
Fiber-to-the-antenna (FTTA) system can be a cost-effective technique for distributing high frequency signals from the head-end office to a number of remote antenna units via passive optical splitter and propagating through low-loss and low-cost optical fibers. Here, we experimentally demonstrate an optical ultra-wideband (UWB) - impulse radio (IR) FTTA system for in-building and in-home applications. The optical UWB-IR wireless link is operated in the W-band (75 GHz - 110 GHz) using our developed near-ballistic unitraveling-carrier photodiode based photonic transmitter (PT) and a 10 GHz mode-locked laser. 2.5 Gb/s UWB-IR FTTA systems with 1,024 high split-ratio and transmission over 300 m optical fiber are demonstrated using direct PT modulation. (C) 2010 Optical Society of America
100 GHz Ultra-wideband Wireless System for the Fiber to the Antenna Networks
(2010)
Chow, C. W.
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Kuo, F. M.
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Shi, J. W.
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Yeh, C. H.
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Wu, Y. F.
We experimentally demonstrate an optical ultra-wideband (UWB) (75GHz-110GHz) fiber-to-the-antenna (FTTA) system using our developed W-band near-ballistic unitraveling-carrier photodiode (NBUTC-PD) based photonic transmitter (PT). 2.5Gb/s and 1.5Gb/s UWB-FTTA systems with 1,024 high split-ratio are demonstrated. (C)2010 Optical Society of America
115 Gbit/s downstream and 10 Gbit/s upstream TWDM-PON together with 11.25 Gbit/s wireless signal utilizing OFDM-QAM modulation
(2014-03-01)
Yeh, C. H.
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Chow, C. W.
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Chen, H. Y.
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Liu, Y. L.
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光電工程學系
In this work, we propose and investigate a 115 Gbit/s (4 x 28.75 Gbit/s) downstream and 10 Gbit/s upstream time- and wavelength-division-multiplexing passive optical network (TWDM-PON) together with 11.25 Gbit/s wireless broadcasting signal using multi-band orthogonal-frequency-divisionmultiplexing (OFDM) modulation within 10 GHz bandwidth. Here, to compensate the power fading and chromatic dispersion in the higher frequency, we utilize a -0.7 chirp parameter Mach-Zehnder modulator (MZM) for the OFDM signal. Hence, negative power penalties of -0.3 and -0.4 dB in the downstream and broadcasting wireless signals; and power penalty of 0.3 dB in the upstream signal are measured at the bit error rate (BER) of 3.8 x 10 (3) after 20 km standard single mode fiber transmission without dispersion compensation. (C) 2013 Elsevier Inc. All rights reserved.
13 Gbit/s WDM-OFDM PON using RSOA-based colourless ONU with seeding light source in local exchange
(2011-10-27)
Chow, C. W.
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Yeh, C. H.
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Wu, Y. F.
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Chen, H. Y.
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Lin, Y. H.
Optical-carrier-distribution using reflective-semiconductor-optical-amplifier (RSOA)-based colorless optical-networking-unit (ONU) is a promising candidate for the wavelength-division-multiplexed passive-optical-network (WDM-PON). However, commercial available RSOA has a typical modulation-bandwidth of similar to 1 GHz, which is not enough for the future bandwidth demand. Here we demonstrate a WDM-PON using 1 GHz bandwidth RSOA-based ONU, which can be operated up to 13 Gbit/s. Experimental results show that 20 km singlemode-fibre transmission of the 13 Gbit/s orthogonal-frequency-division-multiplexed (OFDM) signal can be achieved with bit-error rate lower than the forward error correction threshold.
2.5-10 Gbit/s laser source based on two optical-injection Fabry-Perot laser diodes
(2013-12-01)
Wu, Y. F.
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Yeh, C. H.
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Chow, C. W.
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Liu, Y. L.
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Sung, J. Y.
In this investigation, a wavelength tunable laser source based on optical-injection of two Fabry-Perot laser diodes (FP-LDs) is demonstrated. In the proposed laser source, a self-injection locked master FP-LD provides a stable continuous-wave (CW) lasing, which wavelength can be selected by means of an optical tunable bandpass filter (TBF). The CW wavelength is launched into another FP-LD (the slave laser) for direct signal modulation. In this two optical-injection FP-LD architecture, directly modulation of 2.5 Gbit/s on-off keying (OOK) and 10 Gbit/s orthogonal frequency division multiplexing (OFDM) signals can be achieved in the proposed laser source with negligible power penalty after 25 km single-mode-fiber (SMF) transmission. (C) 2013 Elsevier Inc. All rights reserved.
40-Gb/s downstream DPSK and 40-Gb/s upstream OOK signal remodulation PON using reduced modulation index
(2010-12-06)
Chow, C. W.
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Yeh, C. H.
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光電工程學系
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Department of Photonics
As different high speed signal-remodulation wavelength division multiplexed - passive optical network (WDM-PON) solutions up to 10 Gb/s have been proposed, researchers are going to further increase the data rate of PON towards 40 Gb/s or higher. However, scaling up from 10 Gb/s/wavelength to 40 Gb/s/wavelength PON is very challenging. Although many studies have been performed on upgrading the exiting 10 Gb/s network to 40 Gb/s, the study of the 40 Gb/s signal-remodulation network is very little. In this work, we will first study the chromatic dispersion effect on the signal-remodulation PON. Then, we will propose and demonstrate a signal-remodulation PON using 40-Gb/s downstream differential-phase shift keying (DPSK) and 40-Gb/s upstream on-off keying (OOK) signals. By using the reduced modulation index (RMI) of the downstream DPSK signal, the tolerance to the residual chromatic dispersion of the whole system can be greatly enhanced. Due to the reduced impact of the accumulated chromatic dispersion, the quality of the upstream remodulated OOK signal can be significantly improved. Besides, by detecting the downstream demodulated DPSK signal at the destructive output port of the demodulator, good quality of the demodulated DPSK signal can still be achieved. (C) 2010 Optical Society of America
40-Gb/s Upstream Transmitters Using Directly Modulated 1.55-mu m VCSEL Array for High-Split-Ratio PONs
(2010-03-01)
Chow, C. W.
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Xu, L.
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Yeh, C. H.
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Tsang, H. K.
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Hofmann, W.
We propose and demonstrate a 40-Gb/s symmetric passive optical network with a high split-ratio of 64. The upstream 4 x 10 Gb/s signal is produced by using a directly modulated, uncooled 1.55 mu m monolithic integrated vertical-cavity surface-emitting laser array. The downstream signal is a single-channel 40-Gb/s dark-return-to-zero (DRZ) data, broadcasting information to different optical networking units (ONUs). As the ONU is cost-sensitive, we also demonstrate, by means of simulations, using a 12-Gb/s receiver at the ONU to receive the 40-Gb/s DRZ downstream signal.
400Mbit/s OOK green-LED visible light communication with low illumination
(2018-12-01)
Yeh, C. H.
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Chow, C. W.
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Gu, C. S.
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Guo, B. S.
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Chang, Y. J.
In this work, we propose and demonstrate a LED-based visible light communication (VLC) system. Here, an analog front end (AFE) circuit with optimal equalization design is investigated to enhance the modulation bandwidth of LED. The VLC data rates of 340Mbit/s can be achieved under 1.5-3m free space transmissions with error-free (bit error ratio, BER<1x10(-9)). When the traffic rate is increased to 400Mbit/s, the BER satisfying the forward error correction (FEC) limit (BER=3.8x10(-3)) can be achieved at the low illumination of 34.1 Lux.
A Convergent Wireline and Wireless Time-and-Wavelength-Division-Multiplexed Passive Optical Network
(2015-06-01)
Chow, C. W.
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Sung, J. Y.
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Yeh, C. H.
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光電工程學系
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光電工程研究所
We propose and demonstrate a convergent wireline and wireless access network using time-and-wavelength-division-multiplexed passive optical network (TWDM-PON) architecture. Bidirectional 40-km single-mode-fiber transmissions (including the 60-GHz wireless transmission) satisfying the forward error correction limit are demonstrated, with data rates of similar to 10 Gb/s per wavelength in the downstream signal and 17.50 Gb/s per wavelength in the upstream signal. To achieve higher data rate, bit-loading orthogonal frequency-division modulation was used. We also analyze the laser-linewidth-induced performance variation to the signal generated by optical beating and the baseband signal.
A PRACTICAL IN-HOME ILLUMINATION CONSIDERATION TO REDUCE DATA RATE FLUCTUATION IN VISIBLE LIGHT COMMUNICATION
(2015-04-01)
Chow, C. W.
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Liu, Y.
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Yeh, C. H.
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Sung, J. Y.
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Liu, Y. L.
Visible light communication based on LED has attracted more and more attention. As the primary function of LED luminaries is optimized for lighting and illumination, it challenges the communication properties of VLC. An investigation based on different in-home illumination conditions using commercially available white-light LED luminaries to optimize both illumination and communication is highly desirable. In this work, we investigate joint illumination and communication systems to provide an in-home lighting and VLC system. We first focus on the performance constraints set by illumination properties and discuss lighting conditions using different kinds of commercially available luminaries, beam angles, and LED lamp arrangements, and consider reflections off different wall materials. Then we propose and experimentally demonstrate a white-light phosphor-based LED adaptive data rate VLC system. Finally, the achievable data rates of a joint illumination and VLC system are discussed based on the experimental results, and an environment with reduced VLC data rate fluctuation can be achieved.
A scalable and continuous-upgradable optical wireless and wired convergent access network
(2014-06-02)
Sung, J. Y.
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Cheng, K. T.
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Chow, C. W.
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Yeh, C. H.
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Pan, C. -L.
In this work, a scalable and continuous upgradable convergent optical access network is proposed. By using a multi-wavelength coherent comb source and a programmable waveshaper at the central office (CO), optical millimeter-wave (mm-wave) signals of different frequencies (from baseband to > 100 GHz) can be generated. Hence, it provides a scalable and continuous upgradable solution for end-user who needs 60 GHz wireless services now and > 100 GHz wireless services in the future. During the upgrade, user only needs to upgrade their optical networking unit (ONU). A programmable waveshaper is used to select the suitable optical tones with wavelength separation equals to the desired mm-wave frequency; while the CO remains intact. The centralized characteristics of the proposed system can easily add any new service and end-user. The centralized control of the wavelength makes the system more stable. Wired data rate of 17.45 Gb/s and w-band wireless data rate up to 3.36 Gb/s were demonstrated after transmission over 40 km of single-mode fiber (SMF). (C) 2014 Optical Society of America
A self-protected colorless WDM-PON with 2.5 Gb/s upstream signal based on RSOA
(2008-08-04)
Yeh, C. H.
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Chow, C. W.
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Wang, C. H.
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Shih, F. Y.
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Chien, H. C.
In this investigation, we propose and demonstrate a colorless wavelength division multiplexed passive optical network (WDM-PON) at 2.5 Gb/s using reflective semiconductor optical amplifier (RSOA)-based optical networking units (ONUs); together with a self-protected architecture against fiber fault. In the optical line terminal (OLT), we use an array of self-seeding Fabry-Perot laser diodes (FP-LDs) to provide single-longitudinal-mode (SLM) continuous wave (CW) optical sources for the external injection to the RSOA-based ONUs. The self-survivable function for protecting the fiber fault in the distributed fibers and the proposed network performance are investigated and discussed. (C) 2008 Optical Society of America.
AC-based phosphor LED visible light communication by utilizing novel signal modulation
(2013-10-01)
Liu, Y. F.
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Yeh, C. H.
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Chow, C. W.
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Liu, Y. L.
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光電工程學系
We propose and demonstrate a new AC-light emitting diode based visible light communication system, in which the message signal is up-converted to 400 kHz frequency band and combine with the 60 Hz AC-power from the outlet. A special design bias-tee circuit is first implemented to combine the message signal and the AC-power for minimizing the signal distortion. Thus, the spectra of both signals are well separated. A special design clock recovery is used to synchronize the AC-power with the message signal; hence the message signal can be correctly applied to the rectified AC-power cycle.
Adaptive 84.44-190 Mbit/s phosphor-LED wireless communication utilizing no blue filter at practical transmission distance
(2014-04-21)
Yeh, C. H.
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Chow, C. W.
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Chen, H. Y.
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Chen, J.
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Liu, Y. L.
We propose and experimentally demonstrate a white-light phosphor-LED visible light communication (VLC) system with an adaptive 84.44 to 190 Mbit/s 16 quadrature-amplitude-modulation (QAM) orthogonal-frequency-division-multiplexing (OFDM) signal utilizing bit-loading method. Here, the optimal analogy pre-equalization design is performed at LED transmitter (Tx) side and no blue filter is used at the Rx side. Hence, the similar to 1 MHz modulation bandwidth of phosphor-LED could be extended to 30 MHz. In addition, the measured bit error rates (BERs) of < 3.8 x 10(-3) [forward error correction (FEC) threshold] at different measured data rates can be achieved at practical transmission distances of 0.75 to 2 m. (C) 2013 Optical Society of America
Adaptive Control of OFDM Data Rate for LED Visible Light Communications in Different Free Space Transmission Distances and Offsets
(2012)
Liu, Y. F.
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Yeh, C. H.
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Chow, C. W.
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Liu, Y.
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光電工程學系
Using orthogonal-frequency-division-multiplexing (OFDM) for light-emitting-diode (LED) visible-light-communication (VLC) is a promising approach. Here we demonstrate an LED communication link with adaptive control of the OFDM data rate for different communication environments.
Adaptive scheme for maintaining the performance of the in-home white-LED visible light wireless communications using OFDM
(2013-04-01)
Chow, C. W.
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Yeh, C. H.
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Liu, Y. F.
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Huang, P. Y.
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Liu, Y.
Spectral-efficient orthogonal frequency division multiplexing (OFDM) is a promising modulation format for the light-emitting-diode (LED) optical wireless (OW) visible light communication (VLC). VLC is a directional and line-of-sight communication; hence the offset of the optical receiver (Rx) and the LED light source will result in a large drop of received optical power. In order to keep the same luminance of. the LED light source, we propose and demonstrate an adaptive control of the OFDM modulation-order to maintain the VLC transmission performance. Experimental results confirm the feasibility of the proposed scheme. (C) 2012 Elsevier B.V. All rights reserved.