Mating of optical fibers having angled end faces

Abstract

A method for mating optical fibers, a fiber optic connector, and a fiber optic subassembly are provided in which mating fibers have angled end faces joined by index matching fluid, but in which the angled end faces of the fibers are positioned relative to one another in rotationally misaligned relationship. Applicants discovered unexpectedly that optical fibers can be spliced, to provide satisfactory optical connections, without the need for matched cleaves, and without the need for precise rotational alignment of the cleaves, provided that angled end faces are provided on both the launch and receive fibers and that index matching gel is provided between the angled end faces. Thus, the fibers are mated in positions other than in the precise rotationally aligned position previously believed essential to adequate optical performance. Angled end faces may be positioned less than 165 degrees out of phase.

Description

FIELD OF INVENTION[0001]The present invention relates generally to mating of optical fibers, and more particularly, to mating fibers prepared to have angled end faces.BACKGROUND[0002]Fiber optic communication systems include optical connectors that mate segments of optical fibers. The principal function of an optical fiber connector is to hold a fiber end such that the core of the fiber is axially aligned with the optical path of the fiber component, etc. to which the connector is mated, e.g., so that light from the one fiber is optically coupled to another. This is achieved by holding the end of the fiber such that the core of the fiber is axially aligned with the optical pathway of the mating fiber. By way of example, optical fibers may be mated at a splice, e.g., within a single connector, or may be mated between one or more connectors or optoelectronic devices.[0003]To facilitate an effective optical coupling between a connector and another connector or other device, the end fac...

AI Technical Summary

Benefits of technology

The present invention provides a method for mating optical fibers without the need for precise rotational alignment of the fibers. This is achieved by using angled end faces on both the launch and receive fibers, and applying index matching gel between the angled end faces. The fibers are then mated by positioning their angled end faces close and rotationally misaligned with each other. This avoids the need for precise alignment and allows for random relative rotational orientation of the fibers. The invention also provides a fiber optic connector and subassembly that includes angled end faces positioned in close and rotationally misaligned relationship with each other, with index matching fluid positioned between them to form an optical connection. The angled end faces may be matched or mismatched, and may be rotationally positioned less than 165 degrees out of phase about a common optical axis.

Problems solved by technology

Frequently, however, connectors must be terminated in the field where such facilities and personnel are not available.

However, as the connector temperature departs from the ambient, the refractive index of the gel changes, which increases the reflectance at the splice.

This increase can cause degradation of the optical signal, particularly when coherent light sources are used for signal propagation.

Providing an angled end face tends to cause light reflected at the fiber interface to be reflected at an angle into the cladding of the fiber, rather than back down the fiber core where it can interfere and diminish forward-propagating optical signals.

Keeping the fibers / ferrules properly oriented rotationally is complicated by the fact that the angle of the cleave cannot be perceived by the naked eye.

Accordingly, to avoid rotational misalignment, complex and relatively expensive tools and techniques were developed.

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