Optical-transmission characteristics of optical-fiber cables and installed optical-fiber cable networks for WDM systems

Many cables containing 1.3-/spl mu/m zero-dispersion single-mode (SM) optical fibers are installed in trunk and access networks. Recently, there have been a number of studies on wavelength-division-multiplexing (WDM) systems designed to increase transmission capacity and flexibility. If we can construct WDM systems using SM optical-fiber cable networks designed to transmit using wavelengths in the 1.3-/spl mu/m window (O-band), this will prove very effective in reducing construction costs. It is therefore important to examine the wavelength dependence of the transmission characteristics of SM optical-fiber cables and networks that have already been installed and in which several optical fibers are joined. In this paper, we describe the measured optical characteristics of SM optical-fiber cables and installed optical-fiber cable networks at various wavelengths. The optical characteristics were stable in the 1.46 to 1.625-/spl mu/m wavelength range and we confirmed that the installed SM optical-fiber cable networks could be used for WDM system applications.     

Higher-density single-mode optical fibre cables than 1 fibre/mm2, containing hundreds of fibres

A slotted-rod structure was investigated to obtain the maximum fibre density of high-fibre-count cables. A 500-fibre cable with a fibre density of 1.5 fibres/mm2 was designed and manufactured. The manufactured cable was composed of 10-fibre ribbons inserted into the designed slots. The optical losses of the cabled single-mode fibres were confirmed to be stable at 1.3 and 1.55 ?m. This cable has the highest fibre density of existing optical cables.     

Electrostatically driven fiber-optic micromechanical on/off switchand its application to subscriber transmission systems

The structural design of the switch element is evaluated theoretically and experimentally, and an optimum combination of membrane length and insulator thickness is obtained. Based on the results, a 32-element electrostatically driven switch array is fabricated; its switching performance was found to be excellent. The switch array is applied to a subscriber transmission system using an abnormal subscriber end. A disturbance light from an abnormal subscriber end is successfully interrupted     

Nonmetallic 1000-fiber cable

A nonmetallic high-fiber-count cable that contains fiber ribbons inserted tightly into slots and has tensile force applied to the central and slotted-rod unit strength members is described. The cable bending flexibility, tensile strain, and cable diameter, which are important for its economical and efficient construction, were theoretically and experimentally evaluated and an optimum combination of diameters for the strength members was obtained. Based on the results, a nonmetallic 1000-fiber cable was manufactured and its transmission, mechanical, and water-blocking performances were confirmed to be excellent     

Performance prospects for distributed measurement of Raman gain characteristics in optical fibers

A new technique has already been proposed by the authors for measuring Raman gain characteristics in single-mode optical fibers. The advantage of this technique is that it enables the evaluation of the longitudinal distribution of the Raman gain efficiency in concatenated fibers. With such distributed measurements, it is important to investigate the measurable length, which is determined by the signal-to-noise ratio (SNR) of the detected signal. In this paper, the maximum measurable length available with the previous technique was clarified based on both theoretical and experimental investigation. The SNR of the detected signal has been calculated theoretically, and it has been found that calculated and experimental results were in good agreement. Based on the SNR calculation, the measurable lengths available with this technique for various spatial resolutions and signal wavelengths are discussed.     

Fiber-optic switch arrays for optical subscriber transmissionsystems

Optical array devices play an important role in subscriber transmission systems because they can efficiently accommodate the large number of optical channels required. The use of two single-mode fiber-optic switch arrays in subscriber transmission systems is discussed. The first is a 16-element micromechanical switch array which is electrostatically driven and is used to separate abnormal subscriber units that transmit disturbing light signals. The second is a 16-element switch array which interconnects a pair of probe fibers and any one of 16-channel subscriber-line fibers to execute fault testing     

Ultra-high-density 1000-fibre cable with 5 fibre/mm

An ultra-high-density 1000-fibre cable is proposed, which uses mono-coated low-bending-loss optical fibres with a diameter of 0.25 mm. This cable has great advantages in terms of cable weight and diameter and will be easy to install in a small space in underground ducts. The selection of optical fibre with an optimum low bending loss and cable reliability are investigated experimentally for this cable in order to achieve the maximum fibre density and high reliability. A 1000-fibre cable with a fibre density of 5 fibre/mm and a cable diameter of 15.8 mm was obtained.     

Single-mode optical-fibre ribbon cable

A single-mode optical-fibre ribbon cable was manufactured and investigated. An average cable loss of 0.45 dB/km and average fusion mass-splice loss of 0.35 dB have been achieved at a wavelength of 1.3 ?m. These results indicate that single-mode-fibre ribbon can be applicable to large fibre count transmission.     

Optical fiber cables for residential and business premises

This paper describes a new drop cable, a new cluster-type drop cable for residential premises, a new indoor cable, a new termination cable and a new riser cable for fiber distribution in residential and business premises. The structural design of these cables is investigated and the optimum structures for cost reduction of cable and installation are obtained. Based on the results, these cables are manufactured and their transmission and mechanical characteristics are confirmed to be stable     

Statistical dispersion budgeting method for single-mode fibertransmission systems

A statistical dispersion budgeting method for spliced single-mode fiber transmission spans is proposed. The method aids in the design of fiber spans in high bit-rate (>1 Gb/s) systems. Intended for spans containing many splices, the method yields, in theory, greater span lengths than those calculated with the traditional worst-case dispersion budgeting method