Broadband Light Source Using Fabry Perot Laser Diodes

• US 20080131127A1
• Filed: 12/22/2004
• Published: 06/05/2008
• Est. Priority Date: 12/22/2004
• Status: Active Grant

• Current Assignee: Korea Advanced Institute of Science and Technology
• Original Assignee: Korea Advanced Institute of Science and Technology
• Inventors: Baik, Jin-Serk, Park, Keun-Youl, Lee, Chang-Hee, Min, Hyun-Sik, Choi, Ki-Man
• Granted Patent: US 7,936,994 B2
• Time in Patent Office: Days
• US Class Current: 398/79
• CPC Class Codes: H01S 5/005 Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping H01S5/026, H01S5/18388 take precedence
• CPC Class Codes: H01S 5/0064 Anti-reflection components, e.g. optical isolators
• CPC Class Codes: H01S 5/0427 for applying modulation to the laser
• CPC Class Codes: H01S 5/0612 controlled by temperature
• CPC Class Codes: H01S 5/0656 Seeding, i.e. an additional light input is provided for controlling the laser modes, for example by back-reflecting light from an external optical component H01S5/14, H01S5/4062 and H01S5/4006 take precedence
• CPC Class Codes: H01S 5/4006 Injection locking
• CPC Class Codes: H01S 5/4068 with lateral coupling by axially offset or by merging waveguides, e.g. Y-couplers

Abstract

Disclosed is a broadband light source (BLS) necessary to implement wavelength-locked Fabry-Perot (FP) laser diodes (LDs) applicable to an optical subscriber network The BLS is based on a method using mutual injection of low-cost FP LDs and a method using FP LDs undergoing chirping. A power level of a light emitting diodes (LED), an erbium-doped fiber amplifier (EDFA), or a super luminescent diode (SLD) used as the conventional BLS is low and its cost is high, such that the conventional BLS is inefficient. However, the present invention can easily implement a low-cost BLS using proposed FP LDs.

Claims

1. A method for generating a broadband light source using Fabry-Perot (FP) laser diodes (LDs), comprising:

generating the broadband light source by broadening an oscillation line-width of laser oscillation mode generated from at least two FP LDs by mutual injection of the at least two FP LDs.

2. A method for generating a broadband light source using Fabry-Perot (FP) laser diodes (LDs), comprising:

generating the broadband light source by inducing chirping of a plurality of FP LDs in a way that directly modulates the plurality of FP LDs at a higher frequency than that of a desired transmission rate and by broadening an oscillation line-width of laser oscillation mode.

3. A broadband light source using Fabry-Perot (FP) laser diodes (LDs), comprising:

a pair of FP LDs for generating multimode light; and

an optical coupler for coupling outputs of the pair of FP LDs,

wherein output ports of the pair of FP LDs are coupled to each other such that photons are injected between the pair of FP LDs.

4. The broadband light source of claim 3, further comprising:

an isolator for receiving an output of the optical coupler, blocking reflected light, and passing transmitted light.

5. The broadband light source of claim 3, wherein the optical coupler is a 2×

2 or 1×

2 optical coupler.

6. The broadband light source of claim 3, wherein a transmission bit rate is controlled by adjusting a distance between the pair of FP LDs.

7. The broadband light source of claim 3, wherein an oscillating wavelength of the pair of FP LDs is controlled by adjusting a bias current or temperature of the pair of FP LDs.

8. The broadband light source of claim 3, wherein the pair of FP LDs are antireflection-coated FP LDs or high-power FP LDs.

9. The broadband light source of claim 3, wherein a bandwidth is improved using a broadband FP laser in which a gain band is broad.

10. A broadband light source using Fabry-Perot (FP) laser diodes (LDs), comprising:

N number of FP LDs for generating multimode light; and

an optical coupler for coupling outputs of the N FP LDs,

wherein output ports of the N FP LDs are coupled to one another such that photons are injected between the N FP LDs.

11. The broadband light source of claim 10, further comprising:

an isolator for receiving an output of the optical coupler, blocking reflected light, and passing transmitted light.

12. The broadband light source of claim 10, wherein the optical coupler is one of 1×

2, 2×

2, 1×

N, and N×

N optical couplers.

13. The broadband light source of claim 10, wherein a wavelength interval between oscillation modes is controlled by adjusting a distance between the N FP LDs.

14. The broadband light source of claim 10, wherein an oscillating wavelength of the N FP LDs is controlled by adjusting a bias current or temperature of the N FP LDs.

15. The broadband light source of claim 10, wherein the N FP LDs are antireflection-coated FP LDs or high-power FP LDs.

16. The broadband light source of claim 10, wherein a bandwidth is improved using a broadband FP laser in which a gain band is broad.

17. The broadband light source of claim 10, wherein a plurality of lasers among the N FP LDs are modulated such that a spectrum is increased.

29. An optical transmitter, comprising:

the broadband light source according to claim 10;

a first arrayed waveguide grating (AWG) for filtering light into n number of light components in a plurality of oscillation modes of the broadband light source, where n is the number of output ports of the first AWG or the number of wavelength division multiplexing (WDM) signal channels;

an optical fiber for transmission;

n number of Fabry-Perot (FP) laser diodes (LDs) for outputting light wavelength-locked to a light wavelength injected through the first AWG;

an optical circulator for outputting light input through the first AWG; and

a second AWG for demultiplexing a WDM signal into n number of signals.

30. The optical transmitter of claim 29, further comprising:

an optical fiber amplifier or a polarization controller coupled between the broadband light source and the optical circulator.

31. The optical transmitter of claim 29, wherein the n FP LDs for outputting light wavelength-locked to the light wavelength injected through the first AWG are antireflection-coated FP LDs or high-power FP LDs.

35. A method for generating an unpolarized broadband light source using the broadband light source according to any one of claims 10 and 18, comprising:

using outputs of two output ports of one polarized broadband light source, or dividing and using an output of one output port of one polarized broadband light source, in two polarized broadband light sources for multiplexing polarized light.

36. The method of claim 35, wherein when the outputs of the two output ports of the one polarized broadband light source in the two polarized broadband light sources for multiplexing polarized light are used,

the outputs of the two output ports of the one polarized broadband light source are controlled by first and second polarization controllers, respectively, such that the outputs can be horizontally and vertically polarized light components, and the horizontally and vertically polarized light components are passed to a polarization beam splitter.

37. The method of claim 35, wherein when the outputs of the two output ports of the one polarized broadband light source in the two polarized broadband light sources for multiplexing polarized light are used,

one of the outputs of the two output ports of the one polarized broadband light source is adjusted to be vertical to polarized light of the other output by a wave plate, and polarized light components vertical to each other are passed to a polarization maintaining coupler.

38. The method of claim 35, wherein when the outputs of the two output ports of the one polarized broadband light source in the two polarized broadband light sources for multiplexing polarized light are used,

polarized light components of the outputs of the two output ports of the one polarized broadband light source are adjusted to be vertical to each other by at least one polarization controller, and the polarized light components vertical to each other are passed to a polarization maintaining coupler.

39. The method of claim 35, wherein when the output of the one output port of the one polarized broadband light source in the two polarized broadband light sources for multiplexing polarized light is divided and used,

the output of the one output port of the one polarized broadband light source is separated into two components by a 1×

2 optical coupler, the two components of the optical coupler are adjusted to be horizontally and vertically polarized light components by first and second polarization controllers, and the horizontally and vertically polarized light components are passed to a polarization beam splitter.

40. The method of claim 35, wherein when the output of the one output port of the one polarized broadband light source in the two polarized broadband light sources for multiplexing polarized light is divided and used,

the output of the one output port of the one polarized broadband light source is separated into two components by a 1×

2 optical coupler, one component output from the optical coupler is adjusted to be vertical to polarized light of the other component by a wave plate, and polarized light components vertical to each other are passed to a polarization maintaining coupler.

41. The method of claim 35, wherein when the output of the one output port of the one polarized broadband light source in the two polarized broadband light sources for multiplexing polarized light is divided and used,

polarized light components generated from the output of the one output port of the one polarized broadband light source are adjusted to be vertical to each other by at least one polarization controller, and the polarized light components vertical to each other are passed to a polarization maintaining coupler.

42. An optical transmitter comprising:

the unpolarized broadband light source according to claim 35;

a first arrayed waveguide grating (AWG) for filtering light into n number of light components in a plurality of oscillation modes of the unpolarized broadband light source, where n is the number of output ports of the first AWG or the number of wavelength division multiplexing (WDM) signal channels;

an optical fiber for transmission;

n number of Fabry-Perot (FP) laser diodes (LDs) for outputting light wavelength-locked to a light wavelength injected through the first AWG,

an optical circulator for outputting light input through the first AWG; and

a second AWG for demultiplexing a WDM signal into n number of signals.

43. The optical transmitter of claim 42, further comprising:

an optical fiber amplifier or a polarization controller coupled between the broadband light source and the optical circulator.

44. The optical transmitter of claim 42, wherein the n FP LDs for outputting light wavelength-locked to the light wavelength injected through the first AWG are antireflection-coated FP LDs or high-power FP LDs.

18. A broadband light source using a Fabry-Perot (FP) laser diode (LD), comprising:

an FP LD for generating multimode light; and

a frequency generator for inducing chirping of the FP LD.

19. The broadband light source of claim 18, wherein an oscillating wavelength of the FP LD is controlled by adjusting a bias current or temperature of the FP LD.

20. The broadband light source of claim 18, wherein the FP LD is an antireflection-coated FP LD or high-power FP LD.

21. The broadband light source of claim 18, wherein a bandwidth is improved using a broadband FP laser in which a gain band is broad.

22. The broadband light source of claim 18, wherein mode partition noise is reduced when a spectrum undergoing chirping goes through an optical fiber.

32. An optical transmitter, comprising:

the broadband light source according to claim 18;

a first arrayed waveguide grating (AWG) for filtering light into n number of light components in a plurality of oscillation modes of the broadband light source, where n is the number of output ports of the first AWG or the number of wavelength division multiplexing (WDM) signal channels;

an optical fiber for transmission;

n number of Fabry-Perot (FP) laser diodes (LDs) for outputting light wavelength-locked to a light wavelength injected through the first AWG;

an optical circulator for outputting light input through the first AWG; and

a second AWG for demultiplexing a WDM signal into n number of signals.

33. The optical transmitter of claim 32, further comprising:

an optical fiber amplifier or a polarization controller coupled between the broadband light source and the optical circulator.

34. The optical transmitter of claim 32, wherein the n FP LDs for outputting light wavelength-locked to the light wavelength injected through the first AWG are antireflection-coated FP LDs, high-power FP LDs, or broadband FP LDs.

23. A broadband light source using Fabry-Perot (FP) laser diodes (LDs), comprising:

N number of FP LDs for generating multimode light;

a frequency generator for inducing chirping of the N FP LD; and

an optical coupler for coupling outputs of the N FP LDs.

24. The broadband light source of claim 23, wherein an oscillating wavelength of the N FP LDs is controlled by adjusting a bias current or temperature of the N FP LDs.

25. The broadband light source of claim 23, wherein the N FP LDs are antireflection-coated FP LDs or high-power FP LDs.

26. The broadband light source of claim 23, wherein a bandwidth is improved using a broadband FP laser in which a gain band is broad.

27. The broadband light source of claim 23, wherein the optical coupler is a 1×

N optical coupler.

28. The broadband light source of claim 23, wherein polarized light output from the N FP LDs is adjusted by a polarization controller.