A review is given of the main organizations responsible for optical fiber standards activities, followed by a general discussion of specifiable characteristics of single-mode fibers and test methods for measuring them. The parameters and methods are then discussed in detail, with areas of disagreement amongst standards groups pointed out and directons of future work indicated.

The measurement of the relevant parameters of single-mode optical fibres (namely cut-off wavelength, mode field diameter, chromatic dispersion, refractive-index profile) is discussed, making explicit reference both to the work carried out within CCITT and to original techniques developed by the authors. The main research evolution trends are pointed out.

The initial reason for investigating coherent optical fibre transmission techniques was to determine if the predicted improvements in receiver sensitivity of between 10 to 20 dB over direct detection (1,2) could be achieved in a laboratory experiment. There had been several areas of doubt about the practicability of coherent detection, in particular the spectral properties of semiconductor laser sources, the polarisation characteristics of the fibre transmission medium, the increased complexity of a coherent transmission system and the extensive engineering development that is necessary. Once the practical problems have been reconciled a future for coherent transmission could be forseen, not just for point-to-point long haul telecommunications, but also for wideband signal distribution in local networks. For this second application the extra sensitivity of coherent detection would largely overcome optical path splitting losses and the selectivity of coherent detection could allow many thousands of channels to be frequency multiplexed with a spacing not attainable by other techniques.

The amount of modal noise that appears in a single-mode-fiber communication system depends on the coherence properties of the laser transmitter, the length of the noise-generating fiber present in the system, and the splice losses of the connections to that piece of fiber. This paper shows that the coherence lengths of multi-mode lasers are sufficient to generate modal noise over lengths as long as several tens of meters. Nevertheless, the attenuation of the higher-order mode, even for lasers operated several tens of nm below the effective cutoff wavelength, is sufficient to reduce the modal noise to tolerable levels. From model noise experiments at 90 Mb/s, 432 Mb/s, and 1.7 Gb/s, a fiber design equation is derived that quantifies the relation between the minimum length of fiber that can be used and the maximum amount by which the effective cutoff wavelength can exceed the operating wavelength.

A simple and accurate method for measuring the chromatic dispersion of long spans of single-mode fiber in the vicinity of the minimum-dispersion wavelength is described. Agreement with Nd-YAG/Raman measurements is better than 0.5 ps/km nm within ± 30 nm of the wavelength of minimum-dispersion. Long-haul measurements on recently installed fiber-optic cables will be discussed.

This paper reviews definitions and methods for obtaining equivalent-step-index (ESI) parameters in single-mode fibers. Emphasis is on spot-size determination and extraction of ESI parameters from the data. A simple method which uses far field data to obtain ESI fiber is also described. A comparison is made between different approaches to show advantages and limitations of each. Finally, the usefulness of ESI parameters is discussed.

In this paper four main classes of splicing technique are examined and analysed in terms of loss and complexity. The strategy adopted for field splicing depends critically on the production yield of low concentricity error fibre and on the relative complexity of the power or non power monitored splicing techniques. A comparison of theoretical and experimental splice loss data is presented.

I was asked to address the question, "Is fiber optic standardization a hindrance to technical development?" What I wasn't asked was whether it is the standardization we have or that we don't have that is or is not a hindrance. Since it wasn't specified what was meant, we'll develop this as we go and see what conclusions we reach as to the relationship between standardization and technology.

Single-mode fiber refractive index profiles are determined from the intensity patterns acquired by the Transmitted Near-Field (TNF) method. The formula used for this calculation is derived from the transverse electric field form of the scalar wave equation. In addition, the singularity which occurs as we approach the center of the fiber has been remedied. Theoretical and experimental results are presented for one dimensional TNF intensity distributions.

Optical ray tracing is adapted to single and multi-mode dielectric waveguide theory in order to represent the effects of optics used in coupling optical fibers. The resulting analytical approach provides a practical tool for analyzing performance and developing design criteria for fiber optic connectors and couplers.

The index profile and core diameter of an optical fiber are often obtained by measuring the irradiance distribution at the output of the fiber. In general, a photodiode with a pinhole aperture is used to scan across the irradiance distribution and thus measure the beam profile. Using linear systems theory, we characterize this measurement process as a convolution operation and present the mathematical formalism used to estimate the achievable measurement accuracy. Experimental data are presented which confirm the theoretical results. As an outgrowth of the linear systems analysis, we suggest the use of a scanning slit rather than a pinhole to measure irradiance distributions. We show that the scanning slit is not only easier to implement than the scanning pinhole since it allows more light to be collected, but it also provides accurate beam profile data. Data collected using both techniques (pinhole and slit scanning) are presented and compared for representative beams.

In this paper we review the issues with which the fiber optic LAN planner today must contend. These include the network topology, line control procedures, the choice of medium, whether the medium should be passive or active, the selection of sources, detectors, and connectors, whether the LAN should support one or several services, the use of baseband vs. broadband signaling, and the prospects for LAN standards.

Widespread application of optical fiber technology to short-distance transmission networks is presently hindered by higher costs than existing alternative technologies. Cost reduction can be an important benefit of the design methodology for these systems. This paper proposes a simple, yet accurate design methodology that can reduce system costs based upon technical characteristics of optical fibers designed for local networks. We propose the measurement techniques necessary to implement the method.

The phase space diagram for parabolic and step index fibers leads to a graphic representation of the bound, leaky, and refracted rays of ray theory. This concept is used to predict the attenuation of typical components of local area networks. The technique uses power transfer matrices to track the evolution of power distribution in ray packets. In particular, we predict and then measure the power transfer of two ray packets for a step index fiber. The comparison is encouraging.

A method has been developed that allows to characterize mode sensitive fiber-optic components as well as to predict concatenation effects quite accurately by means of 3x3 mode transition matrices. This characterization method works with fibers of nearly arbitrary index profile. The profile only needs to be monotonic and continuously differentiable. All measurement results are in good agreement with theoretically expected results. Application of the matrix in practice involves multiplication only.

Fused biconical tapered fiber-optic components are very attractive because of their high performance, versatility, low-cost and ease of fabrication. Several new components have been developed using fused tapered and spliced structures, and their modal characteristics were measured. Rotation-splicing has been shown very effective to achieve mode insensitivity at the output ports of such devices.

Preliminary results on development of a fiber optic system for transmitting multiple channels of data over a single optical fiber cable are given. The system employs advanced WDM and TDM techniques to greatly reduce weight and volume of interconnect wiring on modern aircraft. The following components are described: (1) fiber optic receiver for reception of data bursts, (2) a 6 channel TDM (mux and demux) for data rates over 175KBPS per channel, (3) an 8 channel WDM multiplexer and demultiplexer. Problem areas associated with multi-channel (greater than 4) WDM technology are discussed.

Attenuation, strain, and optical time domain reflectometer (OTDR) measurement techniques were applied successfully in the development of a minimum-diameter, electro-optic sea floor cable. Temperature and pressure models for excess attenuation in polymer coated, graded-index fibers were investigated analytically and experimentally using these techniques in the laboratory. The results were used to select a suitable fiber for the cable. Measurements also were performed on these cables during predeployment and sea-trial testing to verify laboratory results. Application of the measurement techniques and results are summarized in this paper.

Design of a hybrid integrated optical/bulk device that spatially separates wavelength multiplexed channels on a ferroelectric substrate is discussed. Parameter optimization yields a 2 millimeter long structure with 50 channels at crosstalk below 60 db and with 0.2% wavelength resolution. It is well understood that development of optoelectronic systems that combine optical and electronic signal processing functions on a single substrate can serve to advance optical communications technology. Recent work demonstrating photodetection in laser recrystallized silicon films on ferroelectric substrates represents a potential contribution to that development. In this paper we discuss characteristics of a demultiplexer that is designed for integration on a ferroelectric substrate as one of several coplanar signal processing devices in an optical wavelength encoded multiple channel communication system. Related though different devices have been previously studied. We have analyzed the properties of the structure shown in Figure 1 for the demultiplexer application. The device consists of a tapered diffused waveguide with a chirped grating that produces radiation out of the plane of the waveguide and into the substrate. The grating period and chirp rate are selected so that the emerging beams focus on either the crystal face opposite the grating or on the same face as the grating. Reflection from the opposite surface is required for the latter case. The chirped grating serves to focus the beams and to spatially disperse beams of different wavelength. Aspects of the design are dictated by fabrication considerations for the silicon detectors that are shown in the figure.

The feasibility of bringing an optical signal through an optical fiber to a detection and processing system at liquid helium temperature was examined. The attenuation of three multimode optical fibers, from two different manufacturers with different buffer coatings, was measured under different cooling conditions. It was found that the attenuation depends on the cooling condition and has hysteresis effects. Independent of the λ tested (0.4 - 1.65 μm) the attenuation stayed below 0.1 dB/m under controlled slow cooling and under 0,5 dB/m with very fast cooling. Therefore, optical fibers can be used to bring optical signals into a liquid helium cooled Dewar for detection and processing.

Performance data of new compact 1.523μm Helium Neon lasers are presented for applications in fiber-optic communication systems. The laser output is single-mode TEM-00 and can be used as an injector for diode laser amplifiers or as a direct source. CW power levels vary between 0.25 and 1.2mW for tube lengths from 6 to 13 inches.

A fiber optic system has been developed to measure single transient gamma rays. The gamma ray signature is converted to light by the Cerenkov process in a 20 cm length of radiation resistant optical fiber. The signal is transmitted over 1 km of optical fiber and detected by state-of-the-art, 175 MHz analog receivers. The receivers are based on silicon PIN detectors with transimpedance hybrid amplifiers and two stages of power amplification. The dc coupled receivers have less than 2% distortion up to 5 volts with less than 10 mV rms noise and a responsivity of 37,500 V/watt at 800 nm. A calibration system measures relative fiber to fiber transit time delays and "system" sensitivity. System bandwidth measurements utilized an electron linear accelerator (Linac) with a 50 ps electron pulse as the Cerenkov light source. The system will be described with supporting calibration and characterization data of parts of the system and the whole system.