Retractable optical fiber assembly

Abstract

A retractable optical fiber assembly includes a housing, a spool rotatably disposed within the housing and an optical waveguide reeled onto the spool. The optical waveguide has a central length of unjacketed optical fiber and shorter end lengths of jacketed optical fiber terminating in optical connectors. The optical waveguide is reeled onto the spool such that the end lengths of jacketed optical fiber are extracted off the spool and retracted onto the spool in the same direction. The spool is biased in a first rotational direction relative to the housing by a torsion spring that exerts a retracting force on the jacketed optical fiber. A mechanical stop is also provided to prevent rotation of the spool in a second rotational direction opposite the first rotational direction. In an exemplary embodiment, the assembly is a test fiber box for use with optical test equipment to test an optical network.

Description

FIELD OF THE INVENTION [0001] The invention relates to a retractable optical fiber assembly. More particularly, the invention relates to a retractable optical fiber assembly that can be used in conjunction with optical test equipment to test, qualify, evaluate, demonstrate, emulate, calibrate, or benchmark an optical system, optical network or optical equipment. In an exemplary embodiment, the invention is a test fiber box for use with an optical time domain reflectometer (OTDR) for testing of an optical network. BACKGROUND OF THE INVENTION [0002] A test fiber box, also commonly referred to as a “launch cord,”“launch cable,”“break-out box,”“dead zone box” or “pulse suppressor” is typically utilized in conjunction with optical test equipment to test, qualify and evaluate the transmission characteristics of optical systems, optical networks or optical equipment. Examples of transmission characteristics include loss, length, time delay and reflectance. Test fiber boxes are primarily in...

AI Technical Summary

Problems solved by technology

However, the use of a conventional test fiber box as a jumper is considered impractical due to weight, bulk, and cost considerations.

The size and weight of conventional test fiber boxes, however, presents several problems.

The test fiber box is generally too large to fit comfortably inside an OTDR transit case and must be transported separately, resulting in possible loss or misplacement of the test fiber box.

If dropped or inadvertently moved, the weight of the test fiber box can cause damage to the OTDR, to the connector adapter in the optical network, or to the components of the test fiber box itself.

Another problem with existing test fiber boxes is that the jacketed optical fiber and the optical connectors on the ends of the jacketed optical fiber are difficult to manage.

The end lengths of jacketed optical fiber can easily become entangled as they are repeatedly unwrapped and rewrapped, thereby causing stress and damage to the optical waveguide (e.g., glass fiber) and jacket.

In addition, the test fiber box may include a protective lid, which may be inadvertently closed and thereby damage the jacketed optical fiber or connectors.

Furthermore, protective caps (e.g., dust caps) for the optical connectors are easily misplaced, thereby subjecting the connectors to possible damage from dust, dirt or debris.

Although existing test fiber boxes provide for storage of the optical waveguide and connectors, that is not their primary purpose.

However, test fiber boxes typically employ relatively long lengths of unjacketed optical fiber to provide sufficient delay time for test signals to propagate.

The known fiber optic storage reels do not provide adequate means for protecting and storing the long length of optical waveguide necessary for a test fiber box within a manageable size assembly.

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