Fiber optic position and shape sensing device and method relating thereto

A fiber optic method for determining the position and shape of an object, the method comprising the steps of:

• a) providing an object;
• b) providing a fiber optic position and shape sensing device comprising:
• a multi-core optical fiber for determining position and shape of the object, the multi-core optical fiber comprising at least two fiber cores spaced apart wherein mode coupling between the fiber cores is minimized, where an array of fiber Bragg gratings is disposed within each fiber core, and
• a frequency domain reflectometer positioned in an operable relationship to the multi-core optical fiber;
• c) affixing the multi-core optical fiber to the object;
• d) measuring with the frequency domain reflectometer strain at a number of points on each core in the optical fiber;
• e) determining a differential strain parameter between the cores at each point along the fiber;
• f) calculating one or more local bend parameters along the fiber based on the determined differential strain parameters;
• and
• g) determining a shape of the object based on the calculated one or more local bend parameters,
• where the number of points is sufficiently large to permit determination of the shape of the object with an accuracy better than one percent of a length of the optical fiber.

A medical instrument system, comprising:

• an elongate instrument body;
• an optical fiber at least partially encapsulated in a wall of the elongate instrument body, the optical fiber including three fiber cores having one or more Bragg gratings;
• a detector corresponding to a frequency domain reflectometer operatively coupled to a proximal end of the optical fiber and configured to detect respective light signals reflected by the one or more Bragg gratings at a number points along each core in the optical fiber;
• and
• a controller operatively coupled to the detector and configured to determine a geometric configuration of at least a portion of the elongate instrument body based on an analysis of the detected reflected portions of the light signals from which differential strain values between the cores at each point along the fiber are determined,
• where the number of points is sufficiently large to permit accurate determination of the geometric configuration of at least a portion of the elongate instrument body with an accuracy better than one percent of a length of the optical fiber.