Showing papers on "Optical Transport Network published in 1987"

Loop-back control apparatus for a loop network having duplicate optical fiber transmission lines

Abstract: A loop-back control apparatus for use in an optical fiber transmission system, wherein it is possible to compensate for faults in opto-electrical and electro-optical converters contained in the optical fiber transmission system. An electrical switch, an optical switch, and duplicate access controllers are provided, the electrical and optical switches being controlled by a control signal generator to enable selection from among the various electro-optical and opto-electrical converters in the event of fault in one of those devices.

A 1.7 gigabit-per-second, time-multiplexed photonic switching experiment

Abstract: Current experimental Ti:LiNbO 3 switching systems need electronics for control, regeneration, and compensation for the imperfections of the photonic switching fabric. These early photonic switches do, however, have advantages over their electronic counterparts: 1) They can carry 100 Mb/s or 10 Gb/s with little modification to the switching fabric, 2) They are synergistic with fiber transmission, especially when optical amplifiers can be used, 3) They provide valuable experience in optics and photonic switching, 4) They give insight into the future of optical switching and how the signaling and protocols of the network need to evolve to accommodate this emerging technology.

Principles and Applications of Nonlinear Optical Elements in Fiber Optics Code Division Multiple Access Networks (FO-CDMA)

Abstract: In this paper we introduce, for the first time, the use of nonlinear optical elements in fiber optics code division multiple access (FO-CDMA) networks using optical orthogonal codes, newly invented sets of orthogonal codes for positive systems, with desired auto- and cross correlation properties. Specifically, we consider a class of nonlinear optical elements in which their nonlinearities are achieved only as a result of their input light intensity. We use optical orthogonal codes to demonstrate the principles and advantages (e.g., reducing the interference signal's intensity) of nonlinear optical elements in FO-CDMA environment. Then, system performance based on optical orthogonal codes and nonlinear optical elements in FO-CDMA is analyzed. For example, we show that, for an error rate of 10?10, FO-CDMA networks with nonlinear optical elements can accommodate 5 times as many more users w.r.t. FO-CDMA networks without the nonlinear optical elements.

All-Optical Fibre Networks For Coal Mines

Abstract: Lublin Technical UniversityP.O.Box 189, Lublin 1, PolandAbstractA topic of the paper is fiber -optic integrated network (FOIN) suited to the most hostileenvironments existing in coal mines. The use of optical fibres for transmission of mineinstrumentation data offers the prospects of improved safety and immunity to electromagneticinterference (EMI). The feasibility of optically powered sensors has opened up new oppor-tunities for research into optical signal processing architectures. This article discussesa new fibre -optic sensor network involving a time domain multiplexing(TDM)scheme and opticalsignal processing techniques. The pros and cons of different FOIN topologies with respect tocoal mine applications are considered. The emphasis has been placed on a recently developedall- optical fibre network using spread spectrum code division multiple access (COMA) tech-niques. The all -optical networks have applications in explosive environments where electri-cal isolation is required.IntroductionWhile currently emphasis on fibre optic applications is being placed on telecommunica-tions for voice and data transfer, the potential of this technology is much wider. Many usesfor fibre optics are in applications that can benefit from the advantages of either size,weight, or immunity to interference that it has over conventional cables. The resourceindustries are just one example of an area where opportunities of this kind are plentiful.Coal mine transmission systemsA typical problem which exists in some mining installations is illustrated in Fig.l.Shafts are used for many purposes, such as transporting ore to the surface, for carryingboth power and communication lines. Due to the heavy electrical currents carried over thepower lines, difficulties are often experienced in the operation of video, voice, and datacommunications links which have cables in the shaft. Also, the monitoring of importantsafety parameters like air quality, presence of methane, operation of equipment, is perfor-med over data links which again are susceptible to interference and also to adverse environ-mental conditions. Therefore optical fibre networks are ideal for use in conditions whichare wet, dirty, corrosive, electrically noisy, or where there is a fire /explosion hazard.A schematic diagram of a coal mine security system is shown in Fig.2. The use of thefibre optic technique in this system opens up a number of possibilities previously difficultto realize. Monitoring responsible factors such as air quality, moisture, temperature,vibration and the presence of methane can now take place at an above- ground control centre.Due to large number of the signals transmitted from the chambers ( Fig.3) multiplexing tech-niques can provide substantial impovements in the transmission efficiency of the system.The use of the FOIN's can solve basic problems related to security of the mines and canprovide rugged, relatively maintenance -free, transmission links. The realisation thatoptical fibres could also be used for sensors and sensing systems has increased rapidly inrecent years./ An all- optical fibre network using optical signal processing and integratedoptical devices will not only provide enormous information capacity but will lead to novelnetwork configurations as well.All- optical TOM networkA schematic diagram of an all- optical network using TOM techniques is shown in Fig.4.The network architecture is matched to the adverse environment of a coal mine. The under-ground part of the network includes optical devices which are entirely sparkless and immuneto EMI. The designing of the TDM network involves a channel bit rate and an opticalloss budget.The required minimum bit rate of the TOM channel is given byCTDM

Network evolution strategies: Network and equipment provider's perspectives

Abstract: This article discusses the common denominators in evolving network strategies T he objective of this theme for ISSLS '86 was to bring together the views of network and equipment providers with respect to the choices they are making in terms of architecture, technology, modernization, and deployment of services. Although it is difficult to draw a clear distinction between this theme and the three others of the symposium, in general the papers in this theme tended to take a large scale, strategic level view primarily from a planning perspective. The papers were organized into 3 sessions. Of the 13 papers, 8 were from operating companies or their affiliates and 5 were from equipment providers and represented a great diversity of approach to a relatively small set of objectives and requirements. Given the differences in market and political environments, the great variety of technology now and soon to be available, it is impossible if not outright dangerous to generalize about the common denominators. Nevertheless, I will attempt to do just that. To a large extent the papers presented took ISDN as a given and focused on issues of developing broadband services and networks, providing local data networking, introducing fiber in the access network for business services, and the introduction of new switching techniques to handle a variety of traffic types. Uniformly, all papers proposed' fiber as the technology of long term choice particularly in those parts of the access network that have large traffic cross-sections. Although there are still some short term applications for multimode fiber particularly over short distances, the trend toward single mode fiber is clear. The distribution of electronics into the outside plant and to customer premises, accompanied by a distribution of intelligence, in some cases giving control directly to the customer is also a common theme. The deve lopmen t of over lay ne tworks in those countries without established CATV systems provides a strong driving force for the development of a fiber-based broadband infrastructure and associated technology. However, these commonalities hide the diversity of architectural approaches, technology choices, introduction rates, and service offerings on the part of administrations and suppliers represented in this session. This diversity although troubling to some certainly makes for interesting conferences and more fundamentally in my opinion expresses a richness of choice which points to an exciting future in this area.