Polarization controlling fiber probe for semiconductor source spectroscopy system

• US 20060132782A1
• Filed: 12/21/2004
• Published: 06/22/2006
• Est. Priority Date: 12/21/2004
• Status: Active Grant

• Current Assignee: Excelitas Technologies Corporation (Excelitas Technologies Holdings LLC)
• Original Assignee: Axsun Technologies Incorporated
• Inventors: Atia, Walid A., Flanders, Dale C., Kuznetsov, Mark E.
• Granted Patent: US 7,230,710 B2
• Time in Patent Office: Days
• US Class Current: 356/432
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0224 using polarising or depolarising elements
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01N 2021/399 Diode laser
• CPC Class Codes: G01N 21/39 using tunable lasers
• CPC Class Codes: G01N 2201/0612 Laser diodes
• CPC Class Codes: G01N 2201/062 LED's
• CPC Class Codes: G01N 2201/08 Optical fibres; light guides

Abstract

A semiconductor source spectroscopy system controls optical power variation of the tunable signal due to polarization dependent loss in the system and thus improves the noise performance of the system. It relies on using polarization control between the source and the sample and/or the sample and the detector.

Claims

1. A semiconductor source spectroscopy system, comprising:

a semiconductor source for generating a signal for illuminating a sample;

a detector for detecting a signal from a sample generated by the illumination of the sample by the semiconductor source; and

polarization controlling fiber in the optical link between the semiconductor source and the detector.

2. A system as claimed in claim 1, wherein the polarization controlling fiber is polarization maintaining fiber.

3. A system as claimed in claim 1, wherein the polarization controlling fiber is optical fiber that propagates only a single polarization.

4. A system as claimed in claim 1, wherein the semiconductor source comprises a superluminescent light emitting diode.

5. A system as claimed in claim 1, wherein the semiconductor source comprises a tunable semiconductor laser source comprising a semiconductor optical amplifier and an intracavity tunable element.

6. A system as claimed in claim 5, wherein the intracavity tunable element is a Fabry-Perot tunable filter.

7. A system as claimed in claim 5, wherein the intracavity tunable element is a microelectromechanical Fabry-Perot tunable filter.

8. A system as claimed in claim 5, wherein the intracavity tunable element is a grating.

9. A system as claimed in claim 1, wherein the semiconductor source comprises a broadband edge emitting, light emitting diode, and the system further comprises a tunable filter for filtering the source signal prior to illuminating the sample making a predispersive spectroscopy system.

10. A system as claimed in claim 1, wherein the semiconductor source comprises an edge emitting, light emitting diode, and the system further comprises a tunable filter for filtering a signal from the sample prior to detection by the detector making a postdispersive spectroscopy system 11. A spectroscopy method, comprising:

generating a signal for illuminating a sample using a semiconductor gain medium;

detecting a signal from a sample generated by the illumination of the sample by the semiconductor gain medium; and

controlling a polarization of signals in an optical link between the semiconductor gain medium and the detector.