Directional coupler with reduced phase distortion
AssigneeHoneywell International Inc.
InventorsMatthew Wade Puckett, Jianfeng Wu, Tiequn Qiu, Steven Tin
Life of this patent
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Abstract
A directional coupler with reduced phase deviation is provided. The directional coupler includes a first coupler waveguide and second coupler waveguide. At least one of a spaced distance between the first coupler waveguide and the second coupler waveguide and a length of the first coupler waveguide and the second coupler waveguide selected to achieve an acceptable phase deviation and a set coupling ratio. The phase deviation is caused by a difference in loss coefficients between a first optical mode in the first coupler waveguide and a second optical mode in the second coupler waveguide.
Claims20
A method of designing a directional coupler with reduced phase deviation, the method comprising:
- setting a coupling ratio of the directional coupler;
- setting a separation distance between a first coupler waveguide and a second coupler waveguide of the directional coupler;
- setting a length of the first coupler waveguide and the second coupler waveguide of the directional coupler;
- determining a phase deviation caused by a difference in loss coefficients between a first optical mode in the first coupler waveguide and a second optical mode in the second coupler waveguide;
- and
- when the determined phase deviation is not acceptable, changing at least one of the separation distance between the first coupler waveguide and the second coupler waveguide and the length of the first coupler waveguide and the second coupler waveguide until an acceptable phase deviation is reached while maintaining the set coupling ratio.
A directional coupler with reduced phase deviation, the directional coupler comprising:
- a first coupler waveguide;
- and
- a second coupler waveguide, at least one of a spaced distance between the first coupler waveguide and the second coupler waveguide and a length of the first coupler waveguide and the second coupler waveguide being selected to achieve an acceptable phase deviation and a set coupling ratio, the phase deviation caused by a difference in loss coefficients between a first optical mode in the first coupler waveguide and a second optical mode in the second coupler waveguide.
A gyroscope comprising:
- a first laser to generate first light waves;
- a second laser to generate second light waves;
- a ring resonator;
- a first directional coupler configured to direct the first light waves into and out of the ring resonator in a clockwise (CW) direction, the first directional coupler including,
- a first coupler waveguide, and
- a second coupler waveguide, at least one of a spaced distance between the first coupler waveguide and the second coupler waveguide and a length of the first coupler waveguide and the second coupler waveguide being selected to achieve an acceptable phase deviation of the first directional coupler and a set coupling ratio, the phase deviation of the first directional coupler caused by a difference in loss coefficients between a first optical mode in the first coupler waveguide and a second optical mode in the second coupler waveguide;
- a second directional coupler configured to direct the first light waves into and out of the ring resonator in a counterclockwise (CCW) direction, the second directional coupler including;
- a third coupler waveguide, and
- a fourth coupler waveguide, at least one of a spaced distance between the third coupler waveguide and the fourth coupler waveguide and a length of the third coupler waveguide and the fourth coupler waveguide selected to achieve an acceptable phase deviation of the second directional coupler and the set coupling ratio, the phase deviation of the second optical coupler caused by a difference in loss coefficients between a first optical mode in the third coupler waveguide and a second optical mode in the fourth coupler waveguide;
- a first pound-Drever-Hall (PDH) loop coupling an output of the first directional coupler to the first laser to stabilize a first frequency of the first light waves out of the first laser;
- a second PDH loop coupling an output of the second directional coupler to the second laser to stabilize a second frequency of the second light waves out of the second laser;
- and
- an subtractor coupled to subtract the second frequency from the first frequency to provide a rate of change output.
Dependencies are inferred from the claim text.