Wen-Piao Lin

Implementation of a new ultrawide-band impulse system

In this letter, we propose a new optically based system to generate ultrawide-band (UWB) impulse signals. The system includes a Fabry-Pe/spl acute/rot laser diode under gain-switched operation and an erbium-doped fiber amplifier used as an external-injection light source to generate optical pulses on the transmitter end, together with a PIN photodiode and a first-order microwave differentiator to convert optical pulses into electrical Gaussian monocycle pulses on the receiver front-end. The experimental and fast Fourier transform analytical results demonstrate that the proposed system can generate UWB impulse signals and provide several gigahertz bandwidths for future applications of high-bit-rate UWB wireless systems.

Design of a new optical impulse radio system for ultra-wideband wireless communications

This study presents a novel optical impulse radio (IR) system for generating Gaussian monocycle pulses for ultrawideband (UWB) radio-over-fiber communications. The proposed system consists of a gain-switched Fabry-Perot laser diode, tunable filter, Er3+-doped fiber amplifier and a microwave differentiator. This new optical technique can tolerate pulse dispersion and avoid the generation of intersymbol interference (ISI) due to its easily adjustable optical pulse width, and can perform better radio communication in terms of generating the UWB signal. Simulated results indicate that the generated Gaussian pulse signal can provide a bandwidth of several gigahertz for the high-bit-rate transmissions. Moreover, experimental and analytical results demonstrate that the proposed system can generate high-quality Gaussian pulse trains for applying future high-bit-rate UWB wireless communications

The modified star-ring architecture for high-capacity subcarrier multiplexed passive optical networks

A modified star-ring architecture (MSRA) consisting of a star network on the upper level and many concatenated ring subnets on the lower level is proposed for subcarrier multiplexed passive optical network (SCM-PON). The upper level star network ensures high network capacity and its weakness in reliability is overcome by the concatenated ring subnets with self-healing capabilities. The self-healing function can be performed at remote nodes (RNs) by using optical switches (OS) to reconfigure the ring subnets if any link fails. Moreover, we design the cascade add/drop transceiver (CAT) structure in the lower level ring subnets to completely eliminate the optical beat interference (OBI) problem and achieve an OBI-free optical network. Finally, we set up an experimental network to demonstrate the feasibility of this cost-effective survivable structure.

A robust fiber-radio architecture for wavelength-division-multiplexing ring-access networks

In this paper, we propose a dynamic wavelength-allocation scheme for wavelength-division multiplexing (WDM) fiber-radio ring-access networks. This scheme can be used to improve the use efficiency of wavelengths at the burst traffic load on the fiber-radio networks. Moreover, a novel bidirectional wavelength add-drop multiplexer (B-WADM) is designed on the backboned ring, which can connect the working and standby sub-rings. It can provide the self-protected function that uses just a few optical devices under link failures. Furthermore, we carry out this study through the simulation and analysis for carrier-to-noise ratio (CNR), channel capacity, and spurious free dynamic range (SFDR) of the fiber-radio network. Finally, we set up an experimental network to demonstrate its performance. The experimental results illustrate that this fiber-radio architecture can provide the robust, flexible, and reliable characteristics for large radio terminals.

A reliable architecture for broad-band fiber-wireless access networks

We propose a broad-band DWDM/SCM fiber-wireless access network based on a two-level bidirectional path-protected ring (BPR) architecture. This architecture can perform self-healing function under link failure. The proposed network can provide high reliability, excellent flexibility and large bandwidth for future broad-band wireless networks. Finally, we set up an experimental fiber-wireless network to demonstrate the feasibility of the proposed architecture.

A self-healing architecture for fiber Bragg grating sensor network

A self-healing architecture for fiber Bragg grating (FBG) sensor networks is proposed and demonstrated. We design remote nodes by using simple optical switches to check the breakpoint and reconfigure the FBG network if any link fails. Moreover, to enhance the signal-to-noise ratio (SNR) of the sensor system, we adopt a fiber laser scheme to construct our proposed self-healing architecture. The fiber laser adopted in this system leads to the SNR over 50 dB for the sensor system. The network survivability of a 10 point FBG sensor is experimentally verified. The proposed system can facilitate a reliable sensor network for a large-scale and multipoint smart structure.

A DWDM/SCM self-healing architecture for broad-band subscriber networks

A high-capacity dense wavelength-division multiplexing/subcarrier multiplexing (DWDM/SCM) network based on a self-healing star-bus-ring architecture (SBRA) is proposed and demonstrated. This architecture has a star subnet on the upper level to be a high-capacity infrastructure for the network, several bus subnets on the middle level to offer broad-band channels for multiwavelength signals, and many ring subnets on the lower level to serve a number of nodes. We design remote nodes and bidirectional wavelength add-drop multiplexers (WADMs) by using simple optical switches to reconfigure the network under link failure. We further employ M-quadrature amplitude modulation (M-QAM) and frequency shift-keyed (FSK) signals for downstream and upstream channels, respectively. The SBRA ensures an optical-beat-interference-free (OBI-free) and high-reliability optical network. Finally, we set up an experimental network to demonstrate the feasibility of the proposed architecture.

Reducing multiple optical carriers interference in broad-band passive optical networks

This letter discusses optical beat interference (OBI) and shows the efficiency in reducing this OBI in the broad-band passive optical network (BPON) by using an extra-strong modulation sine wave. The results show that the optical interference can be reduced to acceptable levels. After calculation, the network with the extra-strong modulation sine wave can be extended to 12 optical network units (ONUs).

Generation of wavelength-tunable optical pulses using EDFA as external-injection light source and amplifier for fabry-Pe/spl acute/rot laser diode

We propose and experimentally demonstrate a system for the generation of wavelength-tunable pulses using a gain-switched Fabry-Pe/spl acute/rot laser diode (FPLD) and an erbium-doped fiber amplifier (EDFA). The EDFA is used as both an external-injection light source and an amplifier for the FPLD. The wavelength tuning is achieved by a tunable filter. The optical sidemode suppression ratio of this system is better than 32 dB over the wavelength-tunable range of 34.5 nm. Moreover, the repetition frequency is 2000 MHz, and the pulsewidth is between 49.3 and 65.3 ps. The whole system is simple and can be easily constructed.

A star-bus-ring architecture for DWDM/SCM passive optical networks

A high-capacity DWDM/SCM PONs based on a star-bus-ring-architecture(SBRA) is proposed and experimentally verified. This architecture can provide high bandwidth, reliability and flexibility for future broadband service networks.