The advent of cost-effective fiberoptics technology has made ubiquitous broadband services, e.g. Broadband-ISDN (B-ISDN), a tomorrow's reality. Even today, large business customers are demanding services for high-speed data transfer and video communications which can only be economically provided with optical fiber. The "cost parity" of fiber with copper is getting very close, and in many instances fiber has proven to be more cost effective. Optical communications technologies have matured, and cost-effective deployment of fiber-based infrastructures for communication services and applications is technically feasible. Successful field trials  have been conducted in many piaces including the U.S., Europe, Japan, and Republic of China (ROC). All new installations, especially in telecommunication-developing countries, have considered using fiber. For examples, Germany is planning an Fiber-To-The-Curb (FTFC) based telephony system for 10 million subscribers in the eastern Gennany. Thailand is installing an FTI'C based telephony system for 2 million subscribers in Bangkok. Singapore has announced to complete its fiber-based infrastructure by 2005. Many telecommunication-developed countries, due to slow growth rates, have set 2015 as the target time frame for completing their fiber-based infrastructures. ROC needs an Island-Wide Fiber Infrastructure (IWFI) to become an information state and be competitive in the global environment. The establishment of the IWFI in Taiwan is of the greatest urgency and importance to ensure an adequate platform to support ROC's communication needs in the remaining decade and the early next century.
A cost-effective method of multiplexing, transmitting and selecting optical video signals is proposed and demonstrated by using appropriate combinations of bi-directional optical trunk- amplifiers, medium-density WDM and optical space switching techniques for rapid cost- effective construction. This paper describes the major factors affecting optical video transport/distribution system design. In particular, a tapping type optical loop-shaped trunk section network is proposed from the viewpoint of system reliability, probability of call-loss and ''B-ISDN with analog overlay''.
We have developed a high precision fusion splicer, which can instantly splice a 12-fiber ribbon at the maximum. By automatic inspection on a fiber ribbon at the stage of pre/post splicing, a estimated splice loss can be inferred through calculation. In the case of splicing a 12-fiber ribbon, the resultant splice losses averaged 0.03 dB, while 2 min. were required for splicing.
In this paper, we propose the idea of wavelength synchronization and construct a novel multiwavelength network--a wavelength synchronized network called Synchronous Wavelength Optical Network (SWONet). Unlike most of the proposed networks featuring distributed light source architectures, the SWONet adopts centralized light source architecture to achieve wavelength synchronization. The SWONet shows many advantages resulting from wavelength synchronization; it also has profound implications on future fiber networking. Specifically, it is a feasible way toward a standard multiwavelength optical network in the future.
Upgrading strategies for B-ISDN systems are investigated and refined by studying the evolution of telephone and broadcasting services. The study suggests that the penetration of B- ISDN could require more than a century. The evolution of B-ISDN for the first thirty years, which is divided into three phases of a period of ten years each, is predicted. Upgrading strategies from phase to phase are investigated both for B-ISDN services and subscriber networks. A typical example of optimizing such strategies is studied to show a possibility of providing attractive services (such as super HDTV with a 2000 lines resolution) at a reasonable cost (such as 2000 dollars per subscriber).
We present a practical configuration of an amplified distributed reflective N-star coupler using 2 X 2 3-dB fiber couplers and least numbers of erbium-doped fibers, pump lasers, and standard fibers. The constitution and characteristics of this coupler are investigated. Besides a tremendous saving of the required standard fibers, this distributed coupler is more efficient, more reliable, more flexible for future expansion, and more cost-effective for application in optical networks.
A subscriber system of optical fiber network is presented. We address the design principles of the splitter-based passive optical network (PON) system developed by Telecommunication Laboratories (TL). The splitter-based PON architecture benefits from sharing optoelectronics and optical loop plants over a number of optical network units (ONUs). The PON system uses 1 X 8 optical couplers to form an 8-way split optical network. The system is capable of delivering 24 digital speech channels over one pair of optical fibers.
Architecture for OC-3 Terminal Multiplexer is presented in this paper, which could be used as a practical implementation guide for SONET OC-3 Terminal Multiplexer. Basic ingredients in SONET are introduced for those who need to be familiar with SONET standard. The hardware architecture including System Control and Transmission is then proposed. A brief introduction to software architecture is also introduced in this paper.
Since the middle and late 1980s, there has been great interest in using subcarrier multiplexing for high capacity lightwave systems. While fiber optic systems are known to give superior performance with digital systems, the present cost of high-speed electronics for processing digital signals continues to make the subcarrier alternative attractive. For these systems, it is useful to have an a-priori knowledge of the distortion produced by a directly modulated laser diode. In this paper, we discuss the harmonic and intermodulation distortion arising from the inherent non-linearity of lasing action manifest in the rate equations. Only analytical techniques are considered. We point out the problem with an approximate harmonic balance technique reported earlier. The main emphasis is on the intermodulation products interfering with subcarriers, as only these products are of interest when the subcarriers are restricted to an octave bandwidth. Earlier analytical work was restricted to two subcarriers and required certain assumptions for determining multicarrier intermodulation distortion. We examine these assumptions in the light of our recent investigations.
The optimal pump period for the least total pump power required for the long-haul transmission system with periodically pumped distributed erbium-doped fiber amplifier is studied numerically. The pump power of the distributed erbium-doped fiber amplifier is minimized with the optimal doping density. It is found that the optimal pump period depends only slightly on the total transmission length.
The main constraint on applying digital intersymbol interference (ISI) cancellation scheme to high-speed optical receivers is the limited processing speed. A novel ISI cancellation technique is given to relax this limitation by doing ISI cancellation merely for some marginal bits near the decision threshold but not for every bit. The proposed 'Soft Decision ISI cancellation' (SDIC) scheme can operate at a speed much lower than the transmission bit rate. The results show that the SDIC scheme can nearly double the transmission distance at BER equals 10-10, and for fixed distance, it can decrease the BER by three orders.
The polarization and modal properties of fiber lasers are theoretically and experimentally analyzed. The polarization properties of the fiber laser is advantageously applied to a novel form of fiber laser sensor.
A quiet but deliberate revolution is taking place in the automobile field. Electronics and optical technologies familiar to the communication engineers are increasingly used in vehicles and in ways we would not have anticipated a decade ago. Optical fibers, head-up displays, holographic reflectors, in-vehicle LAN, cellular and microcellular radio communications, microprocessors for real time analysis and control, distributed intelligence, fiber gyros, integration of devices in optical and electrical connectors, to name a few familiar technologies are all part of the emerging intelligent vehicles and intelligent highways. This paper gives a brief overview of these emerging applications.
Chalcogenide and heavy metal oxide (HMO) glasses doped with various rare-earth elements have been studied for the possibility of developing new solid state laser materials to operate in the mid-infrared. This study investigates the synthesis and optical characterization of As2S3 and Bi2O3-PbO-Ga2O3 glasses doped with rare-earth elements Nd, Er, Ho, Dy, Pr and Tm. Absorption and fluorescence spectra of glasses doped with rare- earths confirmed the presence of trivalent rare-earth ions in the amorphous matrix. As2S3 glasses doped with 0.4 wt% Nd showed strong fluorescence at 1.09 and 1.38 micrometers , while glasses doped with 2.0 wt% Dy exhibited fluorescence at 2.98 and 4.40 micrometers . Further, doping of Ho up to approximately 2.0 wt% showed fluorescence at 2.01 and 3.92 micrometers .
This paper reports the development of a 16-channel and a 8-channel wideband amplified optical power divider with erbium-doped fiber amplifier by using two high power 1480 nm pump LDs in a bidirectional pumping configuration. Over +16 dBm saturation output power was divided by a 16-channel distributed star coupler, and the signal output power from each port was higher than +3 dBm in 1530 nm to 1570 nm wavelength range. It was also determined that a 1 X 8 balanced or unbalanced tree coupler can be integrated into the EDFA module, this constitutes an active optical device for characterizing the optical communication system performance at different signal power levels.
Recent development of low-loss, Er-doped silica fibers has made deployment of optical amplifiers in today's optical communication networks a reality. Among several techniques used for fabricating rare-earth doped fibers, the solution-doping technique offers advantages of versatility and ease of use. Detailed descriptions of the preparation procedures, properties of Er-doped fibers and amplifier performance will be presented.
Fault tolerance determines reliability of local, wide, and metropolitan area networks. Carried- out considerations are addressed to reliability evaluation of the classical, and the enhanced performance double rings, which are configurated according to ShuffleNet interconnection pattern realized by the use of wavelengths dependent signals. The considered multi-channel optical networks are modeled applying the Queuing Theory: the Continuous Time Markov Chains. Introduced models allow to determine in the data networks Mean Time to Failure, Data Throughput, and Time Delay. The results are implemented for performance simulation of advanced fiber optic data networks oriented towards High Speed Data Communications.
Synchronous Optical NETwork (SONET) is a newly adopted transmission standard proposed by Bellcore in 1985. The main purposes of SONET are the mid-span meets (transmission equipment provided by different vendor can be connected directly), management of the entire network in terms of the embedded operation channel, and supporting the application interfaces. SONET Network Element (NE) is the basic equipment in SONET which consists of Terminal Multiplexer (TM), add-drop multiplexer, and digital cross-connect system etc. This paper presents a general guide to design the software architecture of the SONET NE. The object-oriented and layering concepts are heavily used as design rules, which in the future will provide a better approach for designing a product family of the SONET NEs, i.e., reuse the objects. Furthermore, maintenance, testing, and debugging of the software can be easily achieved.
This paper presents a fiber optic simulation methodology for the design of digital lightwave link. Computer-aided analysis of high speed optical data link is important for a system designer to predict the system performance in advanced. Accurate modeling and simulation contribute the fundamental evaluation of optical communication integrated circuit feasibilities. In this paper, the modeling of optical source waveform, transmission fiber, photodetector and timing recovery technique using surface acoustic wave (SAW) filter are discussed. A SONET OC-3 transceiver is simulated as an example, while measured eye diagrams are compared with the simulation result.