US 5,588,077 A · In-line, two-pass, fiber optic rotary joint

Abstract

An especially compact optical rotary joint for use with fiber optic cables is set forth including three embodiments capable of transferring two data streams each carried on a separate optical fiber. The rotary joint is constructed with a stationary portion and a relatively rotating portion. The two optical fiber channels are arranged in-line along the same rotational axis. Isolation of one channel from the other is achieved through a novel application of gradient index rod lenses of suitable pitch. A pair of lenses is arranged adjacent each other on each side of the rotational interface and a second pair of axially aligned lenses is arranged outboard of the first pair. An optical signal from one of the outboard lenses can be directed to one of the other lenses depending on the pitch selection. Losses due to crosstalk or overlap of the signal paths is within acceptable limits. Both channels are bidirectional, i.e., each can carry signals in either direction.

Claims10

Dependent claims

A method of transmitting optical signals along two optical channels across a fiber optic rotary joint, comprising the steps of:

(a) in a rotary joint including a rotational side and a stationary side, connecting first-channel optical fibers with a pair of axially aligned opposing lenses which transmit light between the rotational and stationary sides thereof;
and
(b) inserting second-channel optical fibers between the lenses of the first-channel fibers, aligned to transmit light between the rotating and stationary sides of the rotary joint, so that the light of the second channel will occupy the same physical space as the light of the first channel;
and
(c) wherein channel separation occurs due to the separation of the focal points of the two channels.

2 more elements

A two-channel fiber optic rotary joint for transmission of optical signals, comprising:

(a) a rotational portion aligned with a stationary portion, having a rotational axis extending therealong, and a plane of separation between said rotational and stationary portions;
(b) means for mounting first and second optical fibers in said rotational portion, spaced apart along said axis;
(c) means for mounting third and fourth optical fibers in said stationary portion, spaced apart along said axis;
(d) means for optically coupling first channel light between said first optical fiber and one of said third or fourth optical fibers;
(e) means for optically coupling second channel light between said second optical fiber and the other of said third or fourth fibers so that said second channel light shares the same physical space as said first channel light;
and
(f) the mounting means and the coupling means positioned in said rotational portion on one side of said plane of separation being a mirror image of the mounting means and the coupling means positioned in said stationary portion on the other side of said plane of separation.

4 more elements

Dependencies are inferred from the claim text.

In-line, two-pass, fiber optic rotary joint

Life of this patent

In-line, two-pass, fiber optic rotary joint

Life of this patent

Abstract

Claims10