Quantum cavity light emitting element

• US 5,617,445 A
• Filed: 06/07/1995
• Issued: 04/01/1997
• Est. Priority Date: 06/07/1995
• Status: Expired due to Fees

• Current Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Original Assignee: Picolight Inc (Lumentum Holdings Inc.)
• Inventors: Jewell, Jack L.
• Primary Examiner(s): Davie, James W.
• Application Number:
  US08/483,271
• Time in Patent Office: 664 Days
• Field of Search: 372/39, 372/92, 372/96, 372/50, 372/99
• US Class Current: 372/96
• CPC Class Codes: H01S 5/1042 Optical microcavities, e.g. cavity dimensions comparable to the wavelength
• CPC Class Codes: H01S 5/11 Comprising a photonic bandgap structure
• CPC Class Codes: H01S 5/18308 having a special structure for lateral current or light confinement
• CPC Class Codes: H01S 5/423 having a vertical cavity

Abstract

A quantum cavity light emitting element is provided, comprising first and second mirrors to form a first cavity, at least first and second reflecting surfaces to form a second cavity oriented perpendicularly to the first, and a light emitting material within both cavities. The thickness of the first cavity is designed to enhance emission of light from the light emitting material along the axis of the first cavity, while the second cavity has a predetermined thickness which suppresses emission of light from the light emitting material.

Claims

1. A light emitting element comprising:

at least one light emitting material, said light emitting material emitting light in a wavelength range centered about a center wavelength;

first and second reflecting mirrors at opposite sides of said light emitting material forming a first optical cavity in a first dimension which includes said light emitting material and reflecting mirrors and which enhances emission of light substantially parallel to said first dimension at a wavelength within said wavelength range, at least one of said mirrors being at least partially transparent to light in said wavelength range to allow said light emitted from said light emitting material to be emitted therethrough; and

at least two reflective surfaces oriented substantially perpendicular to said first dimension, said at least two reflective surfaces forming a second optical cavity in a second dimension substantially perpendicular to said first dimension, said second optical cavity being of a predetermined size such that it suppresses emission of light substantially parallel to said second dimension from said light emitting material.

2. The light emitting element recited in claim 1 wherein said at least two reflective surfaces form a shape which is substantially triangular.

3. The light emitting element recited in claim 1 wherein said at least two reflective surfaces form a shape which is substantially rectangular.

4. The light emitting element recited in claim 1 wherein said at least two reflective surfaces form a shape which is substantially square.

5. The light emitting element recited in claim 1 wherein said at least two reflective surfaces form a shape which is substantially hexagonal.

6. The light emitting element recited in claim 1 wherein said at least two reflective surfaces form a shape which is substantially circular.

7. The light emitting element recited in claim 1 wherein said light emitting material in the vicinity of said at least two reflective surfaces has been treated to reduce nonradiative recombination.

8. The light emitting element recited in claim 1 further comprising means for injecting electrical current into said light emitting material.

9. The light emitting element recited in claim 8 further comprising current confining means which confine said electrical current to central portion of said light emitting material.

10. The light emitting element recited in claim 1 wherein said at least two reflective surfaces are formed by etching.

11. The light emitting element recited in claim 1 wherein said at least two reflective surfaces extend through at most one of said first and second mirrors.

12. The light emitting element recited in claim 1 wherein said at least two reflective surfaces are bounded by a dielectric material.

13. The light emitting element recited in claim 12 wherein said dielectric material is substantially air.

14. The light emitting element recited in claim 12 wherein said dielectric material has been deposited and substantially comprises a material from the group of:

polyimide, silicon dioxide, silicon monoxide, silicon nitride.

15. The light emitting element recited in claim 1 wherein said at least two reflective surfaces are bounded by a metallic material.

16. The light emitting element recited in claim 15 wherein said at least two reflective surfaces are insulated from said metallic material.

17. The light emitting element recited in claim 1 wherein said at least two reflective surfaces completely enclose said light emitting element in said second and third dimensions.

18. The light emitting element recited in claim 1 wherein said at least two reflective surfaces do not completely enclose said light emitting element in said second and third dimensions.

19. The light emitting element recited in claim 1 wherein said second optical cavity has resonances in a lowest order mode at a first wavelength and in at least one higher order mode at a second wavelength, said second wavelength being shorter than said first wavelength, said predetermined size of said second optical cavity being such that it suppresses emission of light substantially parallel to said second dimension at both of said first and second wavelengths.

20. The light emitting element recited in claim 1 wherein at least two of said at least two reflective surfaces are substantially parallel and separated by approximately an odd number of quarter wavelengths said quarter wavelengths being measured at said center wavelength.

21. The light emitting element recited in claim 19 wherein at least two of said at least two reflective surfaces are substantially parallel and separated by greater than (N-0.1) quarter wavelengths and by less than (N+0.9) quarter wavelengths where N is an odd numbered integer, said quarter wavelengths being measured at said center wavelength.

22. The light emitting element recited in claim 1 wherein said second optical cavity has standing wave modes, said second optical cavity being of a predetermined size such that it suppresses emission of light in said standing wave modes at a wavelength within said wavelength range.

23. The light emitting element recited in claim 1 wherein said second optical cavity has traveling wave modes, said second optical cavity being of a predetermined size such that it suppresses emission of light in said traveling wave modes at a wavelength within said wavelength range.

24. The light emitting element recited in claim 1 wherein said second optical cavity has standing wave modes, said second optical cavity being of a predetermined size such that it suppresses emission of light in said standing wave modes at a wavelength within said wavelength range, and in which said second optical cavity additionally has traveling wave modes, said second optical cavity being of a predetermined size such that it suppresses emission of light in said traveling wave modes at a wavelength within said wavelength range.

25. The light emitting element recited in claim 1 comprising a plurality of said light emitting elements.

26. The light emitting element recited in claim 25 wherein said at least two reflective surfaces completely enclose said light emitting element in said second and third dimensions.

27. The light emitting element recited in claim 25 wherein said at least two reflective surfaces do not completely enclose said light emitting element in said second and third dimensions.

28. The light emitting element recited in claim 25 wherein at least two reflective surfaces on adjacent light emitting elements are separated by a distance such that they further suppress emission of light substantially parallel to said second dimension at a wavelength within said wavelength range.

29. The light emitting element recited in claim 25 wherein at least two reflective surfaces on adjacent light emitting elements are separated by a distance such that the reflectivities of said at least two reflecting surfaces is increased.

30. The light emitting element recited in claim 25 wherein at least two reflective surfaces on adjacent light emitting elements are separated by approximately an odd number of quarter wavelengths, said quarter wavelengths being measured at said center wavelength.

31. The light emitting element recited in claim 25 wherein at least two reflective surfaces on adjacent light emitting elements are separated by greater than (N-0.1) quarter wavelengths and by less than (N+0.9) quarter wavelengths where N is an odd numbered integer, said quarter wavelengths being measured at said center wavelength.

32. The light emitting element recited in claim 25 wherein at least one light emitting element is activated to emit light and at least one light emitting element is not activated to emit light.

33. The light emitting element recited in claim 1 wherein said light emitting material comprises a semiconductor.

34. The light emitting element recited in claim 33 wherein said semiconductor comprises a compound semiconductor from the group including:

(In,Al,Ga)N, Zn(Se,S), (In,Al,Ga)(As,P), Ga(As,P), (In,Al,Ga)P, (In,Al,Ga)As, (In,Ga)(As,P).

35. The light emitting element recited in claim 1 wherein said light emitting material comprises a an organic material.

36. The light emitting element recited in claim 1 wherein said light emitting element comprises a light emitting diode.

37. The light emitting element recited in claim 1 wherein said light emitting element comprises a laser.

38. The light emitting element recited in claim 37 wherein said light emitting element comprises a vertical cavity surface emitting laser.

39. The light emitting element recited in claim 1 in which at least one of said first and second reflecting mirrors has no substantial reflectance at a wavelength within said wavelength range.

40. The light emitting element recited in claim 1 further comprising at least a third optical cavity oriented substantially perpendicular to said first dimension, said third optical cavity being of a predetermined size such that it suppresses emission of light substantially parallel to said first dimension at a wavelength within said wavelength range.

41. The light emitting element recited in claim 1 in which said second optical cavity has a length greater than two optical wavelengths, said wavelengths being measured at said center wavelength.

42. The light emitting element recited in claim 1, further characterized by an exit surface and further comprising lateral modes, said lateral modes being totally internally reflected at or before said exit surface, said second optical cavity being of a predetermined size such that it suppresses emission of light from said light emitting material into said lateral modes.

43. A light emitting element comprising:

at least one light emitting material, said light emitting material emitting light in a wavelength range centered about a center wavelength;

first and second reflecting mirrors at opposite sides of said light emitting material forming a first optical cavity in a first dimension which includes said light emitting material and reflecting mirrors and which has a resonance near said wavelength range, at least one of said mirrors being at least partially transparent in said wavelength range to allow light emitted from said light emitting material to be transmitted therethrough;

at least two reflective surfaces oriented substantially perpendicular to said first dimension, said at least two reflective surfaces forming a second optical cavity, said second optical cavity being of a predetermined size such that it substantially has no resonances within said wavelength range.

44. A light emitting element comprising:

a plurality of layers stacked along a first dimension and being substantially homogeneous in second and third dimensions perpendicular to said first dimension, said layers comprising at least one light emitting layer, said light emitting layer emitting light in a wavelength range centered about a center wavelength and first and second reflecting mirrors at opposite sides of said light emitting layer forming a first optical cavity in said first dimension which includes said light emitting layer and reflecting mirrors and which has a resonance near said wavelength range, at least one of said mirrors being at least partially transparent in said wavelength range to allow light emitted from said light emitting layer to be transmitted therethrough;

at least two reflective surfaces oriented substantially perpendicular to said first dimension, said at least two reflective surfaces forming a second optical cavity, said second optical cavity being of a predetermined size such that it substantially has no resonances within said wavelength range.

45. A light emitting element comprising:

at least one light emitting material, said light emitting material emitting light in a wavelength range centered about a center wavelength;

first and second reflecting mirrors at opposite sides of said light emitting material forming a first optical cavity in a first dimension which includes said light emitting material and reflecting mirrors and which enhances emission of light substantially parallel to said first dimension at a wavelength within said wavelength range, at least one of said mirrors being at least partially transparent to light in said wavelength range to allow said light emitted from said light emitting material to be emitted therethrough; and

at least two reflective surfaces oriented substantially perpendicular to said first dimension, said at least two reflective surfaces forming a second optical cavity in a second dimension substantially perpendicular to said first dimension, said second optical cavity being of a predetermined size such that it suppresses emission of light substantially parallel to said second dimension at a wavelength within said wavelength range.