Filtered ASE swept source for OCT medical imaging

• US 9,696,471 B2
• Filed: 03/20/2013
• Issued: 07/04/2017
• Est. Priority Date: 09/03/2009
• Status: Expired due to Fees

• Current Assignee: Excelitas Technologies Corporation (Excelitas Technologies Holdings LLC)
• Original Assignee: Axsun Technologies LLC
• Inventors: Flanders, Dale C., Atia, Walid A., Kuznetsov, Mark E.
• Primary Examiner(s): HANSEN, JONATHAN M
• Application Number:
  US13/847,616
• Publication Number:
  US 20130215432A1
• Time in Patent Office: 1,567 Days
• Field of Search: 356479, 356497
• CPC Class Codes: G01B 9/02004 using frequency scans
• CPC Class Codes: G01B 9/02091 Tomographic interferometers, e.g. based on optical coherence
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G01J 3/4338 Frequency modulated spectrometry
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B
• CPC Class Codes: G02B 5/22 Absorbing filters G02B5/201 - G02B5/208 take precedence

Abstract

An integrated swept wavelength optical source uses a filtered ASE signal with an optical amplifier and tracking filter. This source comprises a micro optical bench, a source for generating broadband light, a first tunable Fabry Perot filter, installed on the bench, for spectrally filtering the broadband light from the broadband source to generate a narrowband tunable signal, an amplifier, installed on the bench, for amplifying the tunable signal, and a second tunable Fabry Perot filter, installed on the bench, for spectrally filtering the amplified tunable signal from the amplifier. A self-tracking arrangement is also possible where a single tunable filter both generates the narrowband signal and spectrally filters the amplified signal. In some examples, two-stage amplification is provided. The use of a single bench implementation yields a low cost high performance system. For example, polarization control between components is no longer necessary.

Claims

1. A wavelength swept optical source, comprising:

a micro optical bench;

a source for generating broadband light;

a first tunable Fabry Perot filter, installed on the bench, for spectrally filtering the broadband light from the broadband source to generate a tunable signal, wherein a full width half maximum bandwidth of the first Fabry-Perot tunable filter is less than 20 GHz;

an amplifier, installed on the bench, for amplifying the tunable signal;

at least one filter-amplifier lens, installed on the bench, for coupling the tunable signal from the first tunable Fabry Perot filter into the amplifier;

a second tunable Fabry Perot filter, installed on the bench, for spectrally filtering the amplified tunable signal from the amplifier; and

at least one amplifier-filter lens, installed on the bench, for coupling the tunable signal from the amplifier into the second tunable Fabry Perot filter;

wherein the amplifier is located on the bench optically between the first tunable Fabry-Perot filter and the second tunable Fabry-Perot filter.

2. A wavelength swept optical source as claimed in claim 1, further comprising a hermetic package, the micro optical bench being installed within the hermetic package.

3. A wavelength swept optical source as claimed in claim 2, wherein the hermetic package is a butterfly package.

4. A wavelength swept optical source as claimed in claim 1, further comprising thermoelectric cooler attached to a backside of the optical bench to control a temperature of the optical bench.

5. A wavelength swept optical source as claimed in claim 1, wherein the source comprises a superluminescent light emitting diode, which is installed on the bench.

6. A wavelength swept optical source as claimed in claim 1, wherein the source comprises a semiconductor optical amplifier, which is installed on the bench.

7. A wavelength swept optical source as claimed in claim 1, wherein the first tunable Fabry Perot filter and the second tunable Fabry Perot filter are operated in a reflective mode.

8. A wavelength swept optical source as claimed in claim 1, wherein a full width half maximum bandwidth of the second Fabry-Perot tunable filter is at least 2 times broader in frequency than the bandwidth of the first Fabry-Perot tunable filter.

9. A wavelength swept optical source as claimed in claim 1, wherein a full width half maximum bandwidth of the first Fabry-Perot tunable filter is about 10 GHz or less.

10. A wavelength swept optical source as claimed in claim 1, wherein the amplifier is a semiconductor optical amplifier.

11. A wavelength swept optical source as claimed in claim 1, further comprising a second amplifier for amplifying the amplified tunable signal from the second tunable Fabry Perot filter.

12. A wavelength swept optical source as claimed in claim 1, further comprising an isolator between the first tunable Fabry Perot filter and the amplifier.

13. A wavelength swept optical source as claimed in claim 1, further comprising an isolator between the amplifier and second tunable Fabry Perot filter.

14. An optical tomography system comprising:

a wavelength swept optical source, including;

a micro optical bench, a source for generating broadband light, a tunable Fabry Perot filter, installed on the bench, for spectrally filtering the broadband light from the broadband source to generate a tunable signal, an amplifier, installed on the bench, for amplifying the tunable signal, and at least one filter-amplifier lens, installed on the bench, for coupling the tunable signal from the tunable Fabry Perot filter into the amplifier, wherein a full width half maximum bandwidth of the Fabry-Perot tunable filter is less than 20 GHz; and

an interferometer for transmitting the amplified tunable signals from the wavelength swept optical source to a sample and reference path and combining the optical signals from the sample and the reference path to generate an interference signal.

15. A system as claimed in claim 14, wherein the wavelength swept optical source further includes a second amplifier, installed on the bench, for amplifying the amplified tunable signal from the amplifier.

16. A system as claimed in claim 14, wherein the wavelength optical swept source further includes a second tunable Fabry Perot filter, installed on the bench, for spectrally filtering the amplified tunable signal from the amplifier.

17. A system as claimed in claim 14, further comprising a hermetic package, the micro optical bench being installed within the hermetic package.

18. A system as claimed in claim 17, wherein the hermetic package is a butterfly package.

19. A system as claimed in claim 14, further comprising thermoelectric cooler attached to a backside of the optical bench to control a temperature of the optical bench.

20. A system as claimed in claim 14, wherein the source comprises a superluminescent light emitting diode, which is installed on the bench.

21. A system as claimed in claim 14, wherein the source comprises a semiconductor optical amplifier, which is installed on the bench.

22. A system as claimed in claim 14, wherein the tunable Fabry Perot filter is a microelectromechanical filters.

23. A system as claimed in claim 16, wherein a full width half maximum bandwidth of the second Fabry-Perot tunable filter is at least 2 times broader in frequency than the bandwidth of the first Fabry-Perot tunable filter.

24. A system as claimed in claim 14, wherein a full width half maximum bandwidth of the first Fabry-Perot tunable filter is about 10 GHz or less.

25. A system as claimed in claim 14, wherein the amplifier is a semiconductor optical amplifier.

26. A system as claimed in claim 14, further comprising an isolator between the tunable Fabry Perot filter and the amplifier.