Stress-tuned planar lightwave circuit and method therefor
First Claim
1. A planar-lightwave circuit (PLC) comprising:
- a first waveguide having;
a core that supports the propagation of an optical mode of a first light signal, the optical mode including a first TE-polarization mode and a first TM-polarization mode, the core including a plurality of layers that collectively support the propagation of the optical mode, the plurality of layers comprising a first silicon nitride layer, a second silicon nitride layer, and a silicon dioxide layer that is between the first silicon nitride layer and second silicon nitride layer; and
a top cladding disposed on the core;
a first layer comprising a piezoelectric material, the first layer being disposed on the first waveguide in at least a portion of a first region;
wherein the first layer is dimensioned and arranged to induce a first stress-induced phase shift in the first TE-polarization mode and a second stress-induced phase shift in the first TM-polarization mode in response to a first electric signal applied to the first layer.
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Abstract
A planar lightwave circuit that can be optically coupled with an external device with low optical loss, while also providing low-power functional control over an optical signal propagating through the PLC is disclosed. The PLC includes a high-contrast waveguide region in a stress-inducing (SI) phase shifter is formed such that it can control the phase of the optical signal. The high-contrast-waveguide region is optically coupled to a low-contrast-waveguide region via a spotsize converter, thereby enabling optical coupling to off-chip devices with low optical loss. Formation of the SI phase shifter in a high-contrast-waveguide region enables improved responsivity and phase control, reduced voltage, and smaller required chip real estate. As a result, the present invention enables lower-cost and higher-performance PLC systems.
28 Citations
17 Claims
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1. A planar-lightwave circuit (PLC) comprising:
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a first waveguide having; a core that supports the propagation of an optical mode of a first light signal, the optical mode including a first TE-polarization mode and a first TM-polarization mode, the core including a plurality of layers that collectively support the propagation of the optical mode, the plurality of layers comprising a first silicon nitride layer, a second silicon nitride layer, and a silicon dioxide layer that is between the first silicon nitride layer and second silicon nitride layer; and a top cladding disposed on the core; a first layer comprising a piezoelectric material, the first layer being disposed on the first waveguide in at least a portion of a first region; wherein the first layer is dimensioned and arranged to induce a first stress-induced phase shift in the first TE-polarization mode and a second stress-induced phase shift in the first TM-polarization mode in response to a first electric signal applied to the first layer. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A planar-lightwave circuit (PLC) comprising:
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a first waveguide having a core and a top cladding disposed on the core, wherein the first waveguide has a first region in which the core includes a plurality of layers that collectively support the propagation of a first light signal having a first optical mode that includes a first TE-polarization mode and a first TM-polarization mode, the plurality of layers including a first silicon nitride layer, a second silicon nitride layer, and a silicon dioxide layer that is between the first and second silicon nitride layers; and a stress-inducing (SI) phase shifter that is operatively coupled with the first waveguide in the first region; wherein the SI phase shifter is dimensioned and arranged to induce a stress in at least one layer of the plurality thereof to control a first phase shift in the first TE-polarization mode and a second phase shift in the first TM-polarization mode. - View Dependent Claims (9, 10, 11, 12)
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13. A method for controlling the phase of each of a TE-polarization mode and a TM-polarization mode of a light signal propagating through a first waveguide of a planar-lightwave circuit (PLC), the method comprising:
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providing the first waveguide such that, in a first region, it includes a core that comprises a plurality of dielectric layers that includes a first silicon nitride layer, a second silicon nitride layer, and a silicon dioxide layer that is between the first and second silicon nitride layers, the plurality of dielectric layers collectively supporting an optical mode of the light signal, the optical mode including the TE-polarization mode and TM-polarization mode; providing a first layer comprising a piezoelectric material, the first layer being disposed on the first waveguide; applying a first electric signal to the first layer; and controlling the magnitude of the first electrical signal; wherein the application of the first electric signal to the first layer gives rise to a stress in the first waveguide; and wherein the first layer is dimensioned and arranged such that the stress induces a first stress-induced phase shift in the TE-polarization mode and a second stress-induced phase shift in the TM-polarization mode. - View Dependent Claims (14, 15, 16, 17)
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Specification