Semiconductor micro-resonator device

• US 6,009,115 A
• Filed: 05/04/1999
• Issued: 12/28/1999
• Est. Priority Date: 05/25/1995
• Status: Expired due to Fees

• Current Assignee: Northwestern University
• Original Assignee: Northwestern University
• Inventors: Ho, Seng-Tiong
• Primary Examiner(s): Sanghavi, Hemang
• Application Number:
  US09/304,874
• Time in Patent Office: 238 Days
• Field of Search: 372/6, 372/20, 372/23, 372/26, 372/28, 372/45, 372/46, 372/50, 372/75, 372/92, 372/94, 372/67, 372/97, 372/98, 372/108, 385/24, 385/49, 385/50, 359/124, 359/126, 359/127, 359/132, 359/173, 359/107, 359/333
• US Class Current: 372/92
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02F 1/3133 the optical waveguides being made of semiconducting materials
• CPC Class Codes: G02F 2203/055 wavelength filtering
• CPC Class Codes: G02F 2203/15 involving resonance effects, e.g. resonantly enhanced interaction
• CPC Class Codes: H01S 5/10 Construction or shape of the optical resonator , e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region H01S5/20 takes precedence
• CPC Class Codes: H01S 5/1075 Disk lasers with special modes, e.g. whispering gallery lasers
• CPC Class Codes: H01S 5/34306 emitting light at a wavelength longer than 1000nm, e.g. InP based 1300 and 1500nm lasers
• CPC Class Codes: H01S 5/3434 with a well layer comprising at least both As and P as V-compounds

Abstract

An optical, semiconductor micro-resonator device includes a microcavity resonator and a pair of adjacent waveguides. The microcavity resonator may be formed as a disk, a ring or closed loop with arbitrarily curved circumference with a diameter of approximately 56000λ_lg /n_res or less where λ_lg is the longest operating wavelength of light and n_res is the propagating refractive index. A portion of each of the waveguides is disposed adjacent to the microcavity resonator wherein the adjacent portion may be either tangential to the microcavity resonator or curve about a respective portion of the microcavity resonator. Light propagating in the first waveguide with a wavelength on resonance with the microcavity resonator is coupled thereto via resonant waveguide coupling and from the microcavity resonator the light is coupled to the second waveguide for output therefrom. Light propagating in the first waveguide with a wavelength that is off resonance with the microcavity resonator is not coupled to the microcavity resonator but continues to propagate in the first waveguide for output therefrom. The microcavity resonator and waveguides are formed of semiconductor materials for on-chip integration with other semiconductor devices.

Claims

1. A semiconductor micro-resonator device having a range of operating wavelengths of light including a longest wavelength λ

_lg of light comprising;

a microcavity resonator capable of propagating light and formed of semiconductor materials with a diameter of approximately 56000λ

_lg /n_res or less where n_res is the propagating refractive index of light in the microcavity resonator;

an input waveguide for propagating light therein formed of semiconductor materials and having an input port and an output port, a portion of said input waveguide being disposed adjacent to said microcavity resonator but separated therefrom by a gap that is less than ##EQU2## where n_gap is a propagating refractive index of the gap;

an output waveguide for propagating light therein formed of semiconductor materials having an output port, a portion of said output waveguide being disposed adjacent to said microcavity resonator but separated therefrom by a gap that is less than ##EQU3## where n_gap is a propagating refractive index of the gap;

wherein light propagating in said input waveguide with a wavelength off resonance with said microcavity resonator is output from said output port of said input waveguide and light propagating in said input waveguide with a wavelength on resonance with said microcavity resonator is coupled to said microcavity resonator and from said microcavity resonator to said output waveguide for output from the output port of said output waveguide wherein said microcavity resonator and waveguides are formed of multilayer semiconductors including a substrate, a first cladding layer disposed on top of said substrate, a guiding layer disposed on top of said first cladding layer and a second cladding layer disposed on top of said guiding layer, said guiding layer having a variable refractive index.

2. A semiconductor micro-resonator device as recited in claim 1 wherein the guiding layer has a refractive index variable by an applied voltage.

3. A semiconductor micro-resonator device as recited in claim 1 wherein the guiding layer has a refractive index variable by an injection current to tune the resonance of said micro-resonator device.

4. A semiconductor micro-resonator device as recited in claim 1 wherein the guiding layer is formed of semiconductor materials having quantum wells.

5. A semiconductor micro-resonator device as recited in claim 1 wherein the guiding layer is formed of semiconductor materials having pn junctions.

6. A semiconductor micro-resonator device as recited in claim 1 wherein said guiding layer is formed of Al_x Ga_1-x N where 0≦

x≦

1.

7. A semiconductor micro-resonator device as recited in claim 1 including a plurality of output waveguides disposed adjacent to said microcavity resonator.

8. A semiconductor micro-resonator device as recited in claim 1 wherein said first and/or second cladding layer is a transparent conductor.

9. A semiconductor micro-resonator device as recited in claim 1 wherein said first and/or second cladding layer is InSnO₂.

10. A semiconductor micro-resonator device as recited in claim 1 wherein said microcavity resonator and waveguides are formed by etching said top cladding layer either fully or partially in a pattern defining the outer walls of said microcavity resonator and waveguides.

11. A semiconductor micro-resonator device as recited in claim 1 wherein said microcavity resonator and waveguides are formed from a wafer of said multilayer semiconductor and the outer sidewalls of said microcavity resonator and waveguides are formed by etching said cladding layer and said guiding layer of said wafer in a desired geometry.

12. A semiconductor micro-resonator device as recited in claim 1 wherein said etching extends into said first cladding layer.

13. A semiconductor micro-resonator device having a range of operating wavelengths of light including a longest wavelength λ

_lg of light comprising;

a microcavity resonator capable of propagating light and formed of semiconductor materials with a diameter of approximately 56000λ

_lg /n_res or less where n_res is the propagating refractive index of light in the microcavity resonator;

an input waveguide for propagating light therein formed of semiconductor materials and having an input port and an output port, a portion of said input waveguide being disposed adjacent to said microcavity resonator but separated therefrom by a gap that is less than ##EQU4## where n_gap is a propagating refractive index of the gap;

a plurality of waveguides for propagating light therein, each formed of semiconductor materials and having an output port, a portion of each of said output waveguides being disposed adjacent to said microcavity resonator but separated therefrom by a gap that is less than ##EQU5## where n_gap is a propagating refractive index of the gap;

wherein light propagating in said input waveguide with a wavelength off resonance with said microcavity resonator is output from said output port of said input waveguide and light propagating in said input waveguide with a wavelength on resonance with said microcavity resonator is coupled to said microcavity resonator and from said microcavity resonator to said output waveguides for output from the output ports of said output waveguides.

14. A semiconductor micro-resonator device as recited in claim 13 wherein the guiding layer has a refractive index variable by an applied voltage.

15. A semiconductor micro-resonator device as recited in claim 13 wherein the guiding layer has a refractive index variable by an injection current to tune the resonance of said micro-resonator device.

16. A semiconductor micro-resonator device as recited in claim 13 wherein the guiding layer is formed of semiconductor materials having quantum wells.

17. A semiconductor micro-resonator device as recited in claim 13 wherein the guiding layer is formed of semiconductor materials having pn junctions.

18. A semiconductor micro-resonator device as recited in claim 13 wherein said guiding layer is formed of Al_x Ga_1-x N where 0≦

x≦

1.

19. A semiconductor micro-resonator device as recited in claim 13 wherein said first and/or second cladding layer is a transparent conductor.

20. A semiconductor micro-resonator device as recited in claim 13 wherein said first and/or second cladding layer is InSnO₂.

21. A semiconductor micro-resonator device as recited in claim 13 wherein said microcavity resonator and waveguides are formed by etching said top cladding layer either fully or partially in a pattern defining the outer walls of said microcavity resonator and waveguides.

22. A semiconductor micro-resonator device as recited in claim 13 wherein said microcavity resonator and waveguides are formed from a wafer of said multilayer semiconductor and the outer sidewalls of said microcavity resonator and waveguides are formed by etching said cladding layer and said guiding layer of said wafer in a desired geometry.

23. A semiconductor micro-resonator device as recited in claim 13 wherein said etching extends into said first cladding layer.