VARIABLE LIGHT CONTROLLING DEVICE AND VARIABLE LIGHT CONTROLLING METHOD

Abstract

A variable light controlling device comprising a substrate, an optical waveguide disposed on the substrate, a first heater and a second heater to change the optical waveguide's temperature is fabricated. And a total amount of the power supplied to the first and the second heater, or a total amount of heat emitted from both of the first and second heater, is maintained substantially constant. Then, the substrate is protected from temperature changes, thereby, stable and quick wavelength tuning operations are realized.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The aspects of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings, in which:

FIG. 1 is a top view of a wavelength tunable filter according to a first exemplary embodiment of the present invention.

FIG. 2 is an expanded view of a ring resonator consistent with an exemplary embodiment of the present invention.

FIG. 3 is an expanded view of the A portion shown in FIG. 1.

FIG. 4 is a cross sectional view of the A portion taken along the line B-B shown in FIG. 3.

FIG. 5 is a top view showing how cores are formed consistent with an exemplary embodiment of the present invention.

FIG. 6 is a top view showing how heaters are formed consistent with an exemplary embodiment of the present invention.

FIG. 7 is a top view showing how insulation grooves are formed consistent with an exemplary embodiment of the present invention.

FIG. 8 is an expanded view showing how a heater is formed consistent with an exemplary embodiment of the present invention.

FIG. 9 is a graph describing a resonance operation caused by a resonant spectrum having three types of Free Spectral Ranges (FSRs) consistent with an exemplary embodiment of the present invention.

FIG. 10 is a graph describing principles of wavelength tuning by a plurality of ring resonators consistent with an exemplary embodiment of the present invention. As shown in FIG. 10, (1) denotes a spectrum of a small diameter ring resonator, (2) denotes a spectrum of a large diameter ring resonator, and (3) denotes a synthesized spectrum of the spectra of the small diameter ring resonator illustrated by (1) and the large ring resonator illustrated by (2).

FIG. 11 is a top view of a wavelength tunable filter in a variation of the first exemplary embodiment of the present invention.

FIG. 12 is a top view of a wavelength variable light source according to a second exemplary embodiment of the present invention.

FIG. 13 is a perspective view of the wavelength variable light source according to the second exemplary embodiment of the present invention.

FIG. 14 is a top view of a wavelength variable light source according to a third exemplary embodiment of the present invention.

FIG. 15 is a perspective view of the wavelength variable light source according to the third exemplary embodiment of the present invention.

FIG. 16 is a top view of a wavelength variable light source according to a fourth exemplary embodiment of the present invention.

FIG. 17 is a top view of a wavelength variable light source according to a fifth exemplary embodiment of the present invention.

FIG. 18 is a block diagram of a controlling circuit according to a sixth exemplary embodiment of the present invention.

FIG. 19 is a top view of a variable dispersion compensator according to a seventh exemplary embodiment of the present invention.

Claims

1. A variable light controlling device, comprising: a substrate;an optical waveguide disposed on said substrate;a first heater disposed near said optical waveguide; anda second heater disposed separately from said first heater,wherein a total amount of power supplied to both of said first and second heaters is maintained substantially constant.

2. The variable light controlling device according to claim 1, wherein said first heater is disposed on a first clad in which a core is formed, and wherein said second heater is disposed on a second clad in which no core is formed.

3. The variable light controlling device according to claim 1, further comprising an insulator configured to thermally insulate said first heater and said second heater.

4. The variable light controlling device according to claim 3, wherein said insulator comprises a groove between said first heater and said second heater.

5. The variable light controlling device according to claim 1, wherein said substrate comprises silicon.

6. The variable light controlling device according to claim 1, wherein said second heater is similar in shape to said first heater.

7. The variable light controlling device according to claim 1, further comprising a temperature controlling element which is configured to control a temperature of said substrate.

8. The variable light controlling device according to claim 7, further comprising a temperature detecting element which is configured to detect a temperature of said substrate.

9. The variable light controlling device according to claim 1, wherein said optical waveguide is configured to form at least one resonator.

10. The variable light controlling device according to claim 9, wherein said at least one resonator comprises a ring resonator.

11. The variable light controlling device according to claim 10, wherein said first heater is disposed so as to substantially cover a circumference of said ring resonator.

12. The variable light controlling device according to claim 9, further comprising a light emitting means, wherein, together, said light emitting means and said resonator form an external resonator.

13. A variable light controlling device, comprising: a substrate;an optical waveguide disposed on said substrate;a first heater disposed near said optical waveguide; anda second heater disposed separately from said first heater,wherein a total amount of heat emitted from both of said first and second heaters is maintained substantially constant.

14. The variable light controlling device according to claim 13, wherein said first heater is disposed on a first clad in which a core is formed, and wherein said second heater is disposed on a second clad in which no core is formed.

15. The variable light controlling device according to claim 13, further comprising an insulator configured to thermally insulate said first heater and said second heater.

16. The variable light controlling device according to claim 15, wherein said insulator comprises a groove between said first heater and said second heater.

17. The variable light controlling device according to claim 13, wherein said substrate comprises silicon.

18. The variable light controlling device according to claim 13, wherein said second heater is similar in shape to said first heater.

19. The variable light controlling device according to claim 13, further comprising a temperature controlling element which is configured to control a temperature of said substrate.

20. The variable light controlling device according to claim 19, further comprising a temperature detecting element which is configured to detect a temperature of said substrate.

21. The variable light controlling device according to claim 13, wherein said optical waveguide is configured to form at least one resonator.

22. The variable light controlling device according to claim 21, wherein said at least one resonator comprises a ring resonator.

23. The variable light controlling device according to claim 22, wherein said first heater is disposed so as to substantially cover a circumference of said ring resonator.

24. The variable light controlling device according to claim 21, further comprising a light emitting means, wherein, together, said light emitting means and said resonator form an external resonator.

25. A variable light controlling method, said method comprising: a first heating step comprising heating an optical waveguide which is disposed on a substrate; anda second heating step comprising heating said substrate,wherein a total amount of power supplied during both of said first and second heating steps is maintained substantially constant.

26. A variable light controlling method, said method comprising: a first heating step comprising heating an optical waveguide which is disposed on a substrate; anda second heating step comprising heating said substrate,wherein a total amount of heat emitted during both of said first and second heating steps is maintained substantially constant.