ANALOG EXTERNAL CAVITY LASER

• US 20080219304A1
• Filed: 03/14/2008
• Published: 09/11/2008
• Est. Priority Date: 04/02/2004
• Status: Abandoned Application

• Current Assignee: Frans Kusnadi, John Major, Sabeur Siala, Vladimir Kupershmidt
• Original Assignee: Frans Kusnadi, John Major, Sabeur Siala, Vladimir Kupershmidt
• Inventors: Kupershmidt, Vladimir, Major, John, Siala, Sabeur, Kusnadi, Frans
• Application Number:
  US12/049,055
• Publication Number:
  US 20080219304A1
• Time in Patent Office: Days
• US Class Current: 372/29.02
• CPC Class Codes: H01S 2301/03 Suppression of nonlinear conversion, e.g. specific design to suppress for example stimulated brillouin scattering [SBS], mainly in optical fibres in combination with multimode pumping
• CPC Class Codes: H01S 3/1055 one of the reflectors being constituted by a diffraction grating
• CPC Class Codes: H01S 3/1398 by using a supplementary modulation of the output
• CPC Class Codes: H01S 5/0064 Anti-reflection components, e.g. optical isolators
• CPC Class Codes: H01S 5/0078 for frequency filtering
• CPC Class Codes: H01S 5/02216 Butterfly-type, i.e. with electrode pins extending horizontally from the housings
• CPC Class Codes: H01S 5/02251 using optical fibres
• CPC Class Codes: H01S 5/02325 Mechanically integrated components on mount members or optical micro-benches
• CPC Class Codes: H01S 5/02415 by using a thermo-electric cooler [TEC], e.g. Peltier element
• CPC Class Codes: H01S 5/02438 Characterized by cooling of elements other than the laser chip, e.g. an optical element being part of an external cavity or a collimating lens
• CPC Class Codes: H01S 5/028 Coatings ; Treatment of the laser facets, e.g. etching, passivation layers or reflecting layers
• CPC Class Codes: H01S 5/0427 for applying modulation to the laser
• CPC Class Codes: H01S 5/06804 by monitoring an external parameter, e.g. temperature
• CPC Class Codes: H01S 5/0683 by monitoring the optical output parameters
• CPC Class Codes: H01S 5/0687 Stabilising the frequency of the laser
• CPC Class Codes: H01S 5/141 using a wavelength selective device, e.g. a grating or etalon H01S5/146 takes precedence
• CPC Class Codes: H01S 5/147 having specially shaped fibre, e.g. lensed or tapered end portion
• CPC Class Codes: H01S 5/4012 Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms
• CPC Class Codes: H01S 5/4062 with an external cavity or using internal filters, e.g. Talbot filters
• CPC Class Codes: H01S 5/4087 emitting more than one wavelength

Abstract

The present invention relates to the analog external cavity lasers (ECLs) including designs, materials, methods of manufacturing and methods of use for such ECLs and packages for such ECLs. Numerous criteria are presented that lead to improved cost/performance for ECLs and for systems incorporating such ECLs.

Claims

1-18. -18. (canceled)

19. An optical transmitter comprising:

an external cavity laser for generating an optical signal and transmitting the optical signal over a dispersive fiber optic link;

a first piezoelectric transducer coupled to the external cavity laser;

an electronic circuit coupled to the piezoelectric transducer to change spectral characteristics of the external cavity laser through changing physical properties of the external cavity laser by applying a time varying stress to the external cavity laser, thereby reducing an effect of noise in a received signal arising from stimulated Brillouin scattering (SBS) generated in the dispersive fiber optic link.

20. The optical transmitter of claim 19 arranged so that the optical signal is launched at 1550 nm.

21. The optical transmitter of claim 19 wherein the external cavity laser comprises a semiconductor laser coupled to a fiber Bragg grating (FBG), the optical transmitter arranged so that the time varying stress is applied to the FBG.

22. The optical transmitter of claim 19 wherein the external cavity laser comprises:

a) a light source having a reflective back facet and a transmissive front facet, said light source further comprising a Fabry-Perot gain element with an active length between approximately 300 micrometers and approximately 600 micrometers, wherein said light source has a symmetrical far-field beam profile; and

b) a partially reflective feedback element forming a laser cavity in cooperation with said reflective back facet.

23. The optical transmitter of claim 22 wherein the ratio of mode spacing to the bandwidth of the feedback element is from approximately 0.5 to approximately 1.3.

24. The optical transmitter of claim 19 wherein the first piezoelectric transducer is attached to the external cavity laser.

25. The optical transmitter of claim 19 wherein at least a portion of the external cavity laser is mounted to a substrate and the first piezoelectric transducer is attached to the substrate.

26. The optical transmitter of claim 19 comprising a second piezoelectric transducer, wherein the first piezoelectric transducer is attached to a first side of the external cavity laser and the second piezoelectric transducer is attached to a second side of the external cavity laser, wherein the first side and second side are substantially opposite to each other.

27. The optical transmitter of claim 19 wherein the piezoelectric transducer comprises a piezoelectric coating disposed on the external cavity laser.

28. In an optical system having an optical transmission source comprising a light source optically coupled with an in-line grating to form a laser, a method of lessening effects of noise in a received signal arising from stimulated Brillouin scattering (SBS) generated in a dispersive fiber optic link optically coupled with the laser, the method comprising:

applying a time varying stress to the in-line grating with a first piezoelectric transducer so as to change spectral characteristics of the in-line grating.

29. The method of claim 28 wherein the time varying stress applied to the in-line grating is a periodic stress.

30. The method of claim 28 wherein the spectral characteristics include a refractive index of the grating.

31. The method of claim 28 wherein the in-line grating is a fiber Bragg grating (FBG).

32. The method of claim 28 wherein the laser is a narrow band laser.

33. The method of claim 28, wherein the time varying stress is applied to the grating at a rate that is sufficient to substantially lessen the effects of the SBS.

34. The method of claim 28 wherein the first piezoelectric transducer is attached to the in-line grating.

35. The method of claim 28 wherein the optical system comprises a second piezoelectric transducer, wherein the first piezoelectric transducer is attached to a first side of the in-line grating and the second piezoelectric transducer is attached to a second side of the in-line grating, wherein the first side and second side are substantially opposite to each other.

36. A system comprising:

a dispersive fiber optic link;

a laser optically coupled with the dispersive fiber optic link, wherein the laser includes a narrow band optical source and a fiber Bragg grating (FBG) forming an output facet of the laser; and

first piezoelectric means for dithering the spectral response of the FBG by applying a time varying stress to the FBG to reduce noise in a received signal arising from stimulated Brillouin scattering (SBS) generated in the dispersive optical fiber link.

37. The system of claim 36 wherein the narrow band optical source has a symmetrical far-field beam profile.

38. The system of claim 36 wherein the first piezoelectric means is attached to the FBG.

39. The system of claim 36 wherein the FBG is mounted to a substrate and the piezoelectric means is attached to the substrate.

40. The system of claim 36 comprising a second piezoelectric means, wherein the first piezoelectric means is attached to a first side of the FBG and the second piezoelectric means is attached to a second side of the FBG, wherein the first side and second side are substantially opposite to each other.

41. The system of claim 36 wherein the piezoelectric means comprises a piezoelectric coating disposed on the FBG.

42. The system of claim 36 wherein the laser comprises a feedback element and the ratio of mode spacing to the bandwidth of the feedback element is from approximately 0.5 to approximately 1.3.