Optical pulse reflectometer

• US 6,211,950 B1
• Filed: 07/26/1999
• Issued: 04/03/2001
• Est. Priority Date: 11/29/1996
• Status: Expired due to Fees

• Current Assignee: Deutsche Telekom AG
• Original Assignee: Deutsche Telekom AG
• Inventors: Walter, Herbert
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): MERLINO, AMANDA H
• Application Number:
  US09/308,729
• Time in Patent Office: 617 Days
• Field of Search: 356/73.1, 385/12, 385/13, 385/27, 385/39-42, 385/16
• US Class Current: 356/73.1
• CPC Class Codes: G01M 11/3109 Reflectometers detecting the back-scattered light in the time-domain, e.g. OTDR

Abstract

An optical pulse reflectometer includes switch for selectively connecting a light source to an associated test object and for selectively connecting the test object to an associated photodetector (70). The power utilization and thus the sensitivity is improved over conventional optical pulse reflectometers.

Claims

1. An optical pulse reflectometer comprising:

at least one light source operating in a constant light mode;

at least one test object;

at least one photodetector;

an indication device connected downstream of an output of the at least one photodetector;

at least one optical switch for selectively connecting the light source to the at least one test object and the at least one test object to the at least one photodetector; and

a control device for driving the at least one optical switch so as to produce light pulses having a predefined frequency and duration.

2. The optical pulse reflectometer as recited in claim 1 wherein the at least one light source is a laser diode.

3. The optical pulse reflectometer as recited in claim 1 wherein the at least one test object is an optical fiber.

4. The optical pulse reflectometer as recited in claim 1 wherein the at least one optical switch is at least one of a 2×

2 directional coupler and an acousto-optical modulator.

5. The optical pulse reflectometer as recited in claim 4 wherein an unused port of the at least one optical switch is terminated with a light shielding and absorption device.

6. The optical pulse reflectometer as recited in claim 1 further comprising a launching fiber having a predetermined length, the launching fiber being connected upstream of the at least one test object.

7. The optical pulse reflectometer as recited in claim 1 further comprising a Boxcar averager and a logarithm converter connected between the at least one photodetector and the indication device.