Bell Telephone Laboratories

Lucent Technologies Inc.

American Telephone & Telegraph Co., At&t Bell Laboratories

Western Electric Company, Inc.

Bernard Raymond Eichenbaum

Manuel R Santana

David John DiGiovanni

Andrew Roman Chraplyvy

David Kalish

Raffaele A Sabia

Mujibun Nisa Khan

Charles H Gartside

William B Gardner

Raymond Bradfield Kummer

Janice Bilecky Haber

Francis J Topolski

Basant Kumar Tariyal

Gary Patrick Emery

Dual concentric core fiber is used for optical communication. Inbound messages lying in a first wavelength channel are received from a terminal portion of the fiber, and outbound messages lying in a second such channel are injected into the terminal portion. The optical fiber has at least one annular portion surrounding a central core portion. The inbound messages are received from the annular portion, and the outbound messages are injected into the central core portion. Alternatively, the inbound messages are received from the central core portion, and the outbound messages are injected into the annular portion.

Method and apparatus for bidirectional communication over a single optical fiber

A beam splitter/combiner module for multiplexing and/or demultiplexing a plurality of optical signals having at least three different wavelengths &lgr;,, &lgr;,, and &lgr;,traveling through the module. The module includes a first dichroic mirror having low loss transmission over a first preselected range of wavelengths including &lgr;,and &lgr;,so as to substantially transmit signals having wavelengths &lgr;,and &lgr;,through the first mirror and along an optical signal path of the module. The first dichroic mirror also has high reflectance over a second preselected range of wavelengths including &lgr;,so as to substantially reflect from the first mirror signals having wavelength &lgr;,. A second dichroic mirror, disposed along the optical signal path for receiving from the first mirror the signals transmitted through the first mirror, has low loss transmission over a third preselected range of wavelengths including &lgr;,so as to substantially transmit signals having wavelength &lgr;,through the second dichroic mirror. The second dichroic mirror also has high reflectance over a third preselected range of wavelengths including &lgr;,so as to substantially reflect from the second mirror signals having wavelength &lgr;,.

Beam splitter/combiner module

A high-capacity optical fiber network &lsqb;,&rsqb; includes wavelength-division multiplexing (WDM) within the 1.4 micron (&mgr;m) wavelength region (i.e., 1335-1435 nm). Such a system includes optical fiber &lsqb;,&rsqb; whose peak loss in the 1.4 &mgr;m region is less than its loss at 1310 nm. The optical fiber has a zero dispersion wavelength (&lgr;,) at about 1310 nm, and linear dispersion between about 1.5 and 8.0 ps/nm-km within the 1.4 &mgr;m region. At least three WDM channels operate at 10 Gb/s in the 1.4 &mgr;m wavelength region and have a channel separation of 100 GHz. In one illustrative embodiment of the invention, a broadcast television channel, having amplitude modulated vestigial sideband modulation, simultaneously operates in the 1.3 &mgr;m region (i.e., 1285-1335 nm) and/or the 1.55 &mgr;m region (i.e., 1500-1600 nm). In another embodiment of the invention, 16 digital data channels are multiplexed together in the 1.55 &mgr;m region, each channel operating at about 2.5 Gb/s. Raman amplifiers &lsqb;,&rsqb; are used for amplification in the 1.3 &mgr;m and the 1.4 &mgr;m wavelength regions, whereas an Erbium amplifier &lsqb;,&rsqb; is used for amplification in the 1.55 &mgr;m wavelength region.

Arrangement of optical fiber segments for minimizing effect of nonlinearities

Optical fiber cables have an inner sheath extruded or otherwise applied to surround optical fibers. If the fibers are coupled to the sheath, substantial shrinkage of the sheath during manufacturing induces microbending losses in the optical fibers. The inventive technique involves choosing a sheath material having a low viscoelastic modulus, typically PVC, and the application of tension thereto during or after extrusion that prevents such shrinkage. This approach typically avoids the necessity of including longitudinal compressive strength members in the cable. A filled optical fiber cable having a flexible gel to prevent water entry advantageously uses the present technique.

Sheathed optical fiber cable

A single mode optical fiber ribbon cable is disclosed. In preferred embodiments, the cable comprises a filling compound having a critical yield stress less than about 70 Pa at 20.degree. C. and/or fibers having a coating that comrises a low modulus (less than about 1.5.multidot.10.sup.6 Pa at 20.degree. C.) inner coating and a high modulus (more than 10.sup.8 Pa at 20.degree. C.) outer coating. Communication cable according to the invention can have low cabling loss, is adapted for array joining, can have high fiber density, and can advantageously be used in short-haul applications such as for metropolitan trunk lines or loop, as well as for long-haul applications.

Single mode optical fiber ribbon cable

The forward scattering pattern from a transversely-illuminated polymer-coated optical fiber can be used to insure well-centered coatings on optical fibers. A simple interpretation of the scattering pattern provides an error signal to guide compensatory coating cup alignment. For polymers coating materials with a refractive index higher than that of silica, the scattering pattern contains caustic surfaces. If the coating is eccentric in a direction perpendicular to the incident rays, the positions of the caustic surfaces vary monotonically with eccentricity.

Manufacture of concentric coatings for fiber waveguides

In order to organize a plurality of fiber lightguides (33--33) into a planar array (40), so that they can be bonded together between two tapes (34--34) to form a ribbon (32), the fiber lightguides are payed out from individual supply spools (51--51) and advanced toward a takeup (43). Interposed between the supply spools and the takeup is at least one surface (72) past which the lightguides are advanced and which is effective to organize them contiguously into a single layer array (76). The surface is made with a curvature which is convex in the direction of advance of the fiber lightguides and which is concave in a direction transverse to the direction of advance. The single layer array (76) is advanced past and in engagement with another surface (86) which reforms the array into a planar configuration after which the lightguides are bonded together to form the ribbon (32). A plurality of the ribbons may be formed into a stack which comprises a core (31) of an optical communication cable and which lends itself to group-splicing techniques.

Methods of and apparatus for organizing fiber lightguides into a planar

Microbending loss is reduced and abrasion protection is afforded for optical fibers by relatively thick polymer coatings characterized in part by a preferred elastic tensile modulus and cold flow property. The coating process uses rapid cooling of a liquid application to promote rapid gelation or solidification and thus achieve uniform coating diameter without beading. Fibers so coated are formed into ribbon structures having definite center-to-center fiber spacing. Preparation of coated fibers or ribbon structures for splicing is achieved by solvent stripping of the coating.

Growing community of inventors

Basking Ridge, NJ, United States of America

Bernard Raymond Eichenbaum