Cheng-Ling Ying

Generation and Transmission of BB/MW/MMW Signals by Cascading PM and MZM

A bidirectional three-band lightwave transport system is proposed and experimentally demonstrated for both fiber-to-the-X (FTTX) and radio-over-fiber (RoF) networks. By cascading a phase modulator (PM) and a Mach-Zehnder modulator (MZM) to generate multiple coherent lightwaves, hybrid 1.25 Gbps baseband (BB), 1.25 Gbps/20 GHz microwave (MW), and 1.25 Gbps/40 GHz millimeter-wave (MMW) downstream signals and a 1.25 Gbps BB upstream signal are simultaneously transmitted. Furthermore, with an assistance of an optical signal-to-noise ratio (OSNR) enhancement circuit, sufficient low bit error rate (BER) values are experimentally achieved for both down-link BB/MW/MMW and up-link BB signals. No additional high-frequency local oscillator, mixers and upstream laser diode are required in both transmitter and receiver sites. Under this architecture, both wire-lined and wireless clients can be simultaneously served without using any extra device/equipment to convert the downstream signals among BB, MW and MMW formats.

A Hybrid WDM Lightwave Transport System Based on Fiber-Wireless and Fiber-VLLC Convergences

A hybrid wavelength-division-multiplexing (WDM) lightwave transport system for millimeter-wave (MMW)/microwave (MW)/baseband (BB) signals that are transmission based on fiber-wireless and fiber-visible laser light communication (VLLC) convergences is proposed and demonstrated. A broadband light source with an optical signal-to-noise ratio enhancement scheme in a hybrid lightwave transport system is employed. Light is optically promoted from a 5-Gbps/15-GHz RF data signal to 5-Gbps/60-GHz MMW and 5-Gbps/30-GHz MW data signals in fiber-wireless convergence. Light is also optically demoted from a 5-Gbps/15-GHz RF data signal to a 5-Gbps data stream in fiber-VLLC convergence. Over a 40-km single-mode fiber and a 4-m RF wireless/a 10-m free-space VLLC transmission, bit error rate performs impressively for 60-GHz MMW, 30-GHz MW, and 5-Gbps BB signal transmission. Such a hybrid WDM lightwave transport system could have practical applications for fiber-wireless and fiber-VLLC convergences to provide broadband integrated services.

An Upconverted Phase-Modulated Fiber Optical CATV Transport System

A fiber optical CATV transport system that employed an upconverted technique and a phase modulation scheme to reduce noise and distortion induced by system is proposed and experimentally demonstrated. In contrast to a fiber optical CATV transport system that used a conventional intensity modulation scheme, excellent performances of carrier-to-noise ratio, composite second order, and composite triple beat are obtained in our proposed systems over a 100-km single-mode fiber transmission. It verifies the feasibility of the proposed systems and reveals an outstanding one with excellent transmission performances.

Hybrid lightwave subcarrier CATV/16-QAM/16-QAM OFDM transmission system

A hybrid lightwave subcarrier CATV/16-QAM/16-QAM orthogonal frequency-division multiplexing (OFDM) transmission system employing light injection/optoelectronic feedback techniques and photonic crystal fiber (PCF) is proposed and demonstrated. Good performance of carrier-to-noise ratio (CNR), composite second order, and composite triple beat were obtained for the CATV band, and high CNR and low bit error rate values were achieved for the 16-QAM and 16-QAM OFDM bands over a combination of 80 km single-mode fiber (SMF) and 2.86 km PCF transport.

Novel ROF/FTTX/CATV hybrid three-band transport system.

A novel cost-effective radio-over-fiber (ROF)/fiber-to-the-X (FTTX)/CATV hybrid three-band transport system based on direct modulation of a distributed feedback laser diode (DFB LD) with multi-wavelength output characteristic is proposed and experimentally demonstrated. Radio-frequency (RF) (1.25 Gbps/6 GHz) signal with direct modulation, as well as baseband (BB) (622 Mbps) and CATV (channels 2-78) signals with external remodulation are successfully transmitted simultaneously. Low bit error rate (BER) and clear eye diagram were achieved for ROF and FTTX applications; as well as good performances of carrier-to-noise ratio (CNR), composite second-order (CSO) and composite triple beat (CTB) were obtained for CATV signals over an 80-km single-mode fiber (SMF) transport.

A Bidirectional Hybrid Lightwave Transport System Based on Fiber-IVLLC and Fiber-VLLC Convergences

This paper proposes and validates a bidirectional hybrid lightwave transport system based on fiber-invisible laser light communication (IVLLC) and fiber-visible laser light communication (VLLC) convergences with light injection and optoelectronic feedback techniques. This paper is also the first to employ light injection and optoelectronic feedback techniques in a bidirectional lightwave transport system based on fiber-IVLLC and fiber-VLLC integration. Light is successfully modulated directly with cable television (CATV), 16-quadrature amplitude modulation (QAM), and 16-QAM-orthogonal frequency-division multiplexing (OFDM) signals. Good carrier-to-noise ratio, composite second order, composite triple beat, and bit error rate (BER) are obtained for CATV, 16-QAM, and 16-QAM-OFDM signal transmissions over a combined 40-km single-mode fiber, a 1.43-km photonic crystal fiber, and 6-m free-space transmission. The proposed bidirectional hybrid lightwave transport system exhibits significant potential in providing broadband integrated services, such as CATV, Internet, and telecommunication, via optical fiber and free-space indoor networks.

A full-duplex CATV/wireless-over-fiber lightwave transmission system.

A full-duplex CATV/wireless-over-fiber lightwave transmission system consisting of one broadband light source (BLS), two optical interleavers (ILs), one intensity modulator, and one phase modulator is proposed and experimentally demonstrated. The downstream light is optically promoted from 10Gbps/25GHz microwave (MW) data signal to 10Gbps/100GHz and 10Gbps/50GHz millimeter-wave (MMW) data signals in fiber-wireless convergence, and intensity-modulated with 50-550 MHz CATV signal. For up-link transmission, the downstream light is phase-remodulated with 10Gbps/25GHz MW data signal in fiber-wireless convergence. Over a 40-km single-mode fiber (SMF) and a 10-m radio frequency (RF) wireless transport, bit error rate (BER), carrier-to-noise ratio (CNR), composite second-order (CSO), and composite triple-beat (CTB) are observed to perform well in such full-duplex CATV/wireless-over-fiber lightwave transmission systems. This full-duplex 100-GHz/50-GHz/25-GHz/550-MHz lightwave transmission system is an attractive alternative. This transmission system not only presents its advancement in the integration of fiber backbone and CATV/wireless feeder networks, but also it provides the advantages of a communication channel for higher data rates and bandwidth.

A 20-km/60-Gb/s Two-Way PON Based on Directly Modulated Two-Stage Injection-Locked 1.55-

A 20-km/60-Gb/s two-way passive optical network (PON) based on directly modulated two-stage injection-locked 1.55-μm vertical-cavity surface-emitting laser (VCSEL) transmitters and negative dispersion fibers (NDFs) is proposed and demonstrated. A one-stage injection-locked technique has been confirmed as an effective approach for increasing the frequency response of a VCSEL. A two-stage injection-locked technique, which can further increase the frequency response of a VCSEL, is thereby expected to have excellent transmission performance in a two-way PON. To be the first to employ directly modulated two-stage injection-locked 1.55-μm VCSEL transmitters in a two-way PON, brilliant bit-error-rate performance and a clear eye diagram are obtained over a 20-km NDF transport. A directly modulated VCSEL has a positive chirp, whereas an NDF has a negative dispersion property in the transmission fiber; this negative dispersion property compensates the laser positive chirp and results in systems with better transmission performance. Such an innovative two-way PON provides the advantage of a communication link for high data rates, which is an attractive feature that is useful for broadband network applications.

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A two-way fiber-wireless convergence system based on a two-stage injection-locked 1.55-μm vertical-cavity surface-emitting lasers (VCSELs) transmitter and an optical interleaver (IL) to deliver intensity-modulated and phase-remodulated millimeter-wave (MMW) data signals over a 40-km single-mode fiber (SMF) and a 5-m radio frequency (RF) wireless transport is proposed and experimentally demonstrated. Bit error rate (BER) and eye diagram perform brilliantly through a serious investigation in systems. Such a two-way fiber-wireless convergence system is a promising option, it reveals a prominent one to present its advancement in integration of distribute fiber and in-house network.

VCSEL Transmitters and Negative Dispersion Fibers

Abstract. We propose and experimentally demonstrate a hybrid CATV/16-QAM-Digital CATV/16-QAM-OFDM in-building network over a 40-km single-mode fiber and graded index-plastic optical fiber/10-m visible light communication. The application of external injection technology with the addition of an optoelectronic feedback that raises the resonance frequency of the laser diode results in increased system transmission capability. Good performances of carrier-to-noise ratio, composite second-order, and composite triple-beat are obtained for the CATV signal. A low bit-error-rate value is achieved for the 16-QAM-Digital CATV/16-QAM-OFDM signal.