In-microresonator linear-absorption-based real-time photocurrent-monitoring and tuning with closed-loop control for silicon microresonators
An integrated silicon optical device is capable of being monitored and tuned in real-time. The integrated silicon optical device includes: a bus waveguide, comprising an input port and an output port; an optical microresonator coupled to the bus waveguide, configured to selectively receive light at a desired resonance wavelength from the bus waveguide; a photodetector, configured to electrically read out an operation condition of the optical microresonator; a diode-tuner, configured to blueshift or redshift the resonance wavelength of the optical microresonator; a micro-heater, configured to redshift the resonance wavelength of the optical microresonator; and a control unit, comprising a transimpedance amplifier (TIA) and a microprocessor, configured to implement a two-stage closed-loop tuning scheme.
1. An integrated silicon optical device capable of being monitored and tuned in real-time, comprising:
a bus waveguide, comprising an input port and an output port;
an optical microresonator coupled to the bus waveguide, configured to selectively receive light at a desired resonance wavelength from the bus waveguide;
a photodetector, configured to electrically read out an operation condition of the optical microresonator;
a diode-tuner, configured to blueshift or redshift the resonance wavelength of the optical microresonator;
a micro-heater, configured to redshift the resonance wavelength of the optical microresonator; and
a control unit, comprising a transimpedance amplifier (TIA) and a microprocessor, configured to implement a two-stage closed-loop tuning scheme utilizing the diode-tuner and the micro-heater.
2. The integrated silicon optical device of claim 1 , wherein the waveguide, the microresonator, the photodetector, the diode-tuner, and the micro-heater are fabricated on the same silicon-on-insulator (SOI) substrate.
3. The integrated silicon optical device of claim 1 , wherein the operating wavelengths of the device is in the range of approximately 1300 nm to approximately 1600 nm.
4. The integrated silicon optical device of claim 1 , wherein the integrated silicon optical device of claim 1 is configured to accept a signal received through the input port with a data rate that does not match a data rate of the control unit.
5. The integrated silicon optical device of claim 2 , wherein the photodetector is a linear-absorption-based photodetector.
6. The integrated silicon optical device of claim 5 , wherein the linear-absorption-based photodetector is configured for surface-state absorption at a surface or interface of the linear-absorption-based photodetector.
7. The integrated silicon optical device of claim 5 , wherein the linear-absorption-based photodetector is configured for defect-state absorption in the bulk of a silicon waveguide part of the linear-absorption-based photodetector.
8. The integrated silicon optical device of claim 5 , wherein the microresonator is ring-shaped, and wherein the linear-absorption-based photodetector is a PN diode integrated along a section of a microresonator circumference, where the P and N doped regions spatially overlap with an optical mode in the microresonator.
9. The integrated silicon optical device of claim 5 , wherein the microresonator is ring-shaped, and wherein the linear-absorption-based photodetector is a P-I-N diode integrated along a section of a microresonator circumference, where the I region of the diode spatially overlaps with an optical mode in the microresonator, and the P and N doped regions are located outside the optical mode in the microresonator.
10. The integrated silicon optical device of claim 1 , wherein photocurrent from the photodetector is amplified by the TIA.
11. The integrated silicon optical device of claim 1 , wherein electrical signal from the TIA is an input signal to the two-stage closed-loop tuning scheme.
12. The integrated silicon optical device of claim 1 , wherein the two-stage closed-loop tuning scheme comprises an electro-optical tuning stage and a thermal-optical tuning stage.
13. The integrated silicon optical device of claim 12 , wherein, in the two-stage closed-loop tuning scheme, the electro-optical tuning stage is triggered first relative to the thermal-optical tuning stage.
14. The integrated silicon optical device of claim 13 , wherein, in the two-stage closed-loop tuning scheme, the thermal-optical tuning stage is triggered after the electro-optical tuning stage reaches saturation.
15. The integrated silicon optical device of claim 1 , wherein the diode-tuner is a P-I-N diode integrated along a section of the optical microresonator, where the I region of the diode spatially overlaps with an optical mode in the microresonator, and the P and N doped regions are located outside the optical mode in the microresonator.
16. The integrated silicon optical device of claim 15 , wherein the diode-tuner is configured to utilize an electro-optical free-carrier plasma dispersion effect upon a forward bias voltage across the P-I-N diode.
17. The integrated silicon optical device of claim 1 , wherein the diode-tuner is a PN diode integrated along a section of the optical microresonator, where the P and N doped regions spatially overlap with an optical mode in the microresonator.
18. The integrated silicon optical device of claim 17 , wherein the diode-tuner is configured to utilize an electro-optical free-carrier plasma dispersion effect upon a reverse bias voltage across the PN diode.
19. The integrated silicon optical device of claim 17 , wherein the diode-tuner is configured to utilize an electro-optical free-carrier plasma dispersion effect upon a forward bias voltage across the PN diode.
20. The integrated silicon optical device of claim 1 , wherein the micro-heater is an integrated silicon resistor located to the inside of the microresonator or located to the outside of the microresonator.
21. The integrated silicon optical device of claim 1 , wherein the micro-heater is a layer of metal resistor that is located on top of the microresonator.
22. The integrated silicon optical device of claim 1 , wherein the micro-heater is configured to utilize a thermal-optical effect in silicon.
23. The integrated silicon optical device of claim 1 , wherein the microresonator is a circular-shaped ring resonator.
24. The integrated silicon optical device of claim 1 , wherein the microresonator is a non-circular-shaped ring resonator.
25. The integrated silicon optical device of claim 1 , wherein the microresonator is a circular-shaped microdisk.
26. The integrated silicon optical device of claim 1 , wherein the integrated silicon optical device is an electro-optical modulator.
27. The integrated silicon optical device of claim 1 , wherein the integrated silicon optical device is part of a high-order coupled-microresonator-based optical device having multiple microresonators that are identical in design or have sizes that follow the Vernier effect design;
wherein the multiple microresonators are serially-coupled to each other as a coupled resonator optical waveguide (CROW) or parallel-coupled to waveguides as side-coupled integrated spaced sequences of resonators (SCISSORs);
wherein the multiple microresonators are monitored and tuned by the control unit; and
wherein, in the two-stage closed-loop tuning scheme, triggering tuning for a particular microresonator is based on an operation condition for a microresonator coupled to the particular microresonator.
28. The integrated silicon optical device of claim 1 , wherein the integrated silicon optical device is part of an optical integrated circuit comprising various kinds of optical devices with multiple microresonators;
wherein the multiple microresonators are monitored and tuned by the control unit; and
wherein, in the two-stage closed-loop tuning scheme, triggering tuning for a particular microresonator is based on an operation condition for a microresonator coupled to the particular microresonator.
29. An optical filter capable of being monitored and tuned in real-time, comprising:
an input waveguide configured to carry optical signals in multiple wavelengths;
an output waveguide;
an optical microresonator coupled to the input and output waveguides to selectively transfer optical signals of at least one desired resonance wavelength from a plurality of optical signals of multiple wavelengths from the input waveguide to the output waveguide;
a photodetector, configured to electrically read out an operation condition of the optical microresonator;
a diode-tuner, configured to blueshift or redshift the resonance wavelength of the optical microresonator;
a micro-heater, configured to redshift the resonance wavelength of the optical microresonator;
a control unit, comprising a transimpedance amplifier (TIA) and a microprocessor, configured to implement a two-stage closed-loop tuning scheme utilizing the diode-tuner and the micro-heater.
30. An electro-optical switch capable of being monitored and tuned in real-time, comprising:
a multimode-interference-based waveguide crossing with four ports, including an input port and an output port;
an optical microresonator coupled to the multimode-interference-based waveguide crossing to selectively transfer light at a desired resonance wavelength received from the input port to the output port;
a photodetector, configured to electrically read out an operation condition of the optical microresonator;
a diode-tuner, configured to blueshift or redshift the resonance wavelength of the optical microresonator;
a micro-heater, configured to redshift the resonance wavelength of the optical microresonator;
a control unit, comprising a transimpedance amplifier (TIA) and a microprocessor, configured to implement a two-stage closed-loop tuning scheme utilizing the diode-tuner and the micro-heater.
31. The electro-optical switch of claim 30 , wherein the electro-optical switch is part of a two-dimensional array of identically designed cascaded electro-optical switches of an optical router, wherein the control unit is configured to perform real-time monitoring and tuning of all of the switching elements of the two-dimensional array, and wherein, in the two-stage closed-loop tuning scheme, triggering tuning for a particular microresonator is based on an operation condition for a prior-coupled microresonator in the two-dimensional array.