Apparatus for coupling an optical fiber to a structure at a desired angle

• US 5,448,662 A
• Filed: 02/24/1993
• Issued: 09/05/1995
• Est. Priority Date: 02/12/1992
• Status: Expired due to Fees

• Current Assignee: Goodrich Corporation (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: DeGroot, Peter J., Kittell, David H., Hayes, Guy H.
• Primary Examiner(s): Mintel, William
• Assistant Examiner(s): TRAN, MINH LOAN
• Application Number:
  US08/021,711
• Time in Patent Office: 923 Days
• Field of Search: 385/25, 385/75, 385/90, 385/53-76, 385/88-94, 385/136-140, 385/147
• US Class Current: 385/25
• CPC Class Codes: G01B 5/0014 due to temperature on machine tools B23Q11/0003

Abstract

Optical metrology apparatus, specifically a laser probe (1), includes a frame (10) comprised of a material selected to have a predetermined coefficient of thermal expansion. A beamsplitter (36) is coupled to the frame for generating a sample beam optical path (D) and a reference beam optical path (C). The beamsplitter is optically coupled to an optical fiber (12) that delivers radiation to and conveys radiation from the frame. A piezoelectric stack (48) has an excitation signal coupled thereto and includes a mirror (26) for phase modulating the reference beam optical path length in response to the excitation signal. The laser probe includes a first strain gauge (58) that is coupled to the piezoelectric stack and a second strain gauge (60) that is coupled to the frame. A closed loop control system (A1, A2, A3, A4, VR) varies the excitation signal in accordance with the detected strains so as to maintain the reference beam optical path length in a predetermined relationship to a path length of the sample beam optical path. This athermalizes the probe, in that any expansion or contraction of the frame is matched by the piezoelectric stack, yielding a net zero change in the non-common beam path lengths. The apparatus includes an optical fiber support (14) that is rotatably coupled to the frame for positioning the optical fiber at a desired angular position.

Claims

1. Apparatus for coupling an optical fiber to a structure comprising:

a fiber support mandrill for securable receiving said optical fiber;

an elongated ball member having an elongated body and a first end for receiving said mandrill and a tapered, slightly rounded second end;

a clamp having a rounded recess for receiving said slightly rounded second end such that said ball member and mandrill rotate said optical fiber to the desired angle relative to a surface of the structure; and

means for securing said clamp to said structure to fix the desired angle.

2. The apparatus of claim 1 wherein said first end is slightly rounded.