Method and apparatus for tuning a Bragg grating in a semiconductor substrate

• US 6,947,616 B2
• Filed: 01/02/2003
• Issued: 09/20/2005
• Est. Priority Date: 06/13/2001
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Liu, Ansheng, Paniccia, Mario J., Nicolaescu, Remus
• Primary Examiner(s): Nguyen, Thong
• Assistant Examiner(s): Pritchett, Joshua L
• Application Number:
  US10/335,765
• Publication Number:
  US 20030133658A1
• Time in Patent Office: 992 Days
• Field of Search: 385/2, 385/8, 385/10, 385/129, 385/130, 385/132, 359/237, 359/245, 359/288, 359/289
• US Class Current: 385/10
• CPC Class Codes: G02B 2006/12097 Ridge, rib or the like
• CPC Class Codes: G02B 2006/12135 Temperature control
• CPC Class Codes: G02B 6/124 Geodesic lenses or integrated gratings
• CPC Class Codes: G02F 1/0147 based on thermo-optic effects G02F1/132 takes precedence
• CPC Class Codes: G02F 1/025 in an optical waveguide structure G02F1/017, G02F1/2257 take precedence
• CPC Class Codes: G02F 2201/307 Reflective grating, i.e. Bragg grating

Abstract

A tunable Bragg grating method and apparatus. In one aspect of the present invention, a method according to an embodiment of the present invention includes directing an optical beam into a first end of an optical path having the first end and a second end disposed in a semiconductor substrate, reflecting a first portion of the optical beam having a first center wavelength back out from the first end of the optical path and tuning the optical path to reflect a second portion of the optical beam having a second center wavelength back out from the first end of the optical path. In one embodiment, the Bragg grating is tuned with a heater used to adjust a temperature of the semiconductor substrate. In another embodiment, charge in charge modulated regions along the optical path is modulated to tune the Bragg grating.

Claims

1. An apparatus, comprising:

a semiconductor substrate layer;

a heater disposed proximate to the semiconductor substrate layer;

an optical path through the semiconductor substrate layer, wherein a temperature of the semiconductor substrate layer including the optical path is responsive to the heater;

a plurality of silicon and polysilicon regions disposed in the semiconductor substrate layer along the optical path forming a Bragg grating having a Bragg wavelength, the Bragg wavelength responsive to the temperature of the semiconductor substrate layer;

a first optical confinement layer disposed proximate to the semiconductor substrate layer; and

a second optical confinement layer disposed proximate to the semiconductor substrate layer such that the semiconductor substrate layer is disposed between the first and second optical confinement layers.

2. The apparatus of claim 1 further comprising an optical waveguide disposed in the semiconductor substrate layer, the optical waveguide including the optical path.

3. The apparatus of claim 2 wherein the optical waveguide disposed in the semiconductor substrate layer comprises an optical rib waveguide.

4. The apparatus of claim 1 further comprising a second semiconductor layer such that the second optical confinement layer is disposed between the semiconductor substrate layer and the second semiconductor layer.

5. The apparatus of claim 4 wherein the semiconductor substrate layer, the second semiconductor substrate layer, the first optical confinement layer and the second optical confinement layer are included in a silicon-on-insulator wafer.

6. The apparatus of claim 1 wherein the plurality of silicon and polysilicon regions disposed in the semiconductor substrate layer along the optical path provide a periodic perturbation of a refractive index along the optical path.

7. The apparatus of claim 6 wherein the Bragg grating comprises a uniform Bragg grating disposed in the semiconductor substrate layer.

8. The apparatus of claim 1 wherein the plurality of silicon and polysilicon regions disposed in the semiconductor substrate layer along the optical path are provided a quasi-periodic perturbation of a refractive index along the optical path.

9. The apparatus of claim 8 wherein the Bragg grating comprises an apodized Bragg grating disposed in the semiconductor substrate layer.

10. The apparatus of claim 1 wherein the heater comprises a thin-film heater.

11. An apparatus, comprising:

a semiconductor substrate;

an optical path through the semiconductor substrate;

a plurality of charge modulated regions disposed along the optical path within the semiconductor substrate to establish a Bragg grating having a plurality of perturbations of a refractive index along the optical path;

a first optical confinement layer disposed proximate to the semiconductor substrate; and

a second optical confinement layer disposed proximate to the semiconductor substrate such that the semiconductor substrate is disposed between the first and second optical confinement layers.

12. The apparatus of claim 11 further comprising an optical waveguide disposed in the semiconductor substrate, the optical waveguide including the optical path.

13. The apparatus of claim 12 wherein the optical waveguide disposed in the semiconductor substrate includes an optical rib waveguide.

14. The apparatus of claim 11 further comprising:

an insulating layer disposed proximate to the semiconductor substrate; and

a plurality of conductive elements disposed proximate to the insulating layer such that the insulating layer is disposed between the plurality of conductive elements and the semiconductor layer, the plurality of conductive elements coupled to receive a modulation signal, the plurality of charge modulated regions coupled to be modulated in response to the modulation signal.

15. The apparatus of claim 14 wherein the insulating layer comprises the first optical confinement layer.

16. The apparatus of claim 11 wherein the plurality of perturbations of the refractive index of the semiconductor substrate along the optical path are provided with periodic changes in a geometry of the optical path in the semiconductor substrate along the optical path.

17. The apparatus of claim 16 wherein the periodic changes in the geometry of the optical path provide a uniform Bragg grating disposed in the semiconductor substrate.

18. The apparatus of claim 11 wherein the plurality of perturbations of the refractive index of the semiconductor substrate along the optical path are provided with quasi-periodic changes in a geometry of the optical path in the semiconductor substrate along the optical path.

19. The apparatus of claim 18 wherein the quasi-periodic changes in the geometry of the optical path provide an apodized Bragg grating disposed in the semiconductor substrate.