Silicon-based optical modulator for analog applications
First Claim
1. An analog optical modulator formed within an SOI structure including a silicon substrate, an overlying oxide layer and a relatively thin silicon surface waveguiding layer, the analog optical modulator comprisingan optical interferometer formed within the relatively thin silicon surface waveguiding layer, the interferometer including an input optical waveguide, a pair of parallel waveguiding arms and an output optical waveguide, with an input Y-splitter disposed between the input optical waveguide and an input to the pair of parallel waveguiding arms and an output Y-combiner disposed between an output of the pair of parallel waveguiding arms and the output optical waveguide, a continuous wave (CW) optical input signal coupled into the input optical waveguide;
- andat least one silicon-insulator-silicon capacitance (SISCAP) optical waveguiding device disposed in at least one of said pair of parallel waveguiding arms, the SISCAP optical waveguiding device comprisinga first silicon region within the relatively thin silicon surface waveguiding layer doped to exhibit a first conductivity type;
a second silicon region disposed to overlap, in part, the first silicon region, the second silicon region doped to exhibit a second, opposite conductivity type;
a relatively thin dielectric layer disposed in an overlap area between said first and second doped silicon regions, a combination of said first and second doped silicon regions with the interposed relatively thin dielectric layer defining an active region of an electro-optic device;
a voltage bias applied across the at least one SISCAP optical waveguiding device to create a predetermined, constant capacitance value across the at least one SISCAP optical waveguiding device, thereby forming a linear operating region for the analog optical modulator; and
an input RF electrical signal coupled to the second silicon region of the at least one SISCAP device, wherein the application of said input RF electrical signal, in combination with the voltage bias, modifies a phase of an optical signal passing therethrough to create a modulated analog optical output signal along the optical output waveguide, the modulated analog optical output signal replicating the input RF electrical signal.
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Abstract
A silicon-insulator-silicon capacitive (SISCAP) optical modulator is configured to provide analog operation for applications which previously required the use of relatively large, power-consuming and expensive lithium niobate devices. An MZI-based SISCAP modulator (preferably a balanced arrangement with a SISCAP device on each arm) is responsive to an incoming high frequency electrical signal and is biased in a region where the capacitance of the device is essentially constant and the transform function of the MZI is linear.
53 Citations
14 Claims
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1. An analog optical modulator formed within an SOI structure including a silicon substrate, an overlying oxide layer and a relatively thin silicon surface waveguiding layer, the analog optical modulator comprising
an optical interferometer formed within the relatively thin silicon surface waveguiding layer, the interferometer including an input optical waveguide, a pair of parallel waveguiding arms and an output optical waveguide, with an input Y-splitter disposed between the input optical waveguide and an input to the pair of parallel waveguiding arms and an output Y-combiner disposed between an output of the pair of parallel waveguiding arms and the output optical waveguide, a continuous wave (CW) optical input signal coupled into the input optical waveguide; - and
at least one silicon-insulator-silicon capacitance (SISCAP) optical waveguiding device disposed in at least one of said pair of parallel waveguiding arms, the SISCAP optical waveguiding device comprising a first silicon region within the relatively thin silicon surface waveguiding layer doped to exhibit a first conductivity type; a second silicon region disposed to overlap, in part, the first silicon region, the second silicon region doped to exhibit a second, opposite conductivity type; a relatively thin dielectric layer disposed in an overlap area between said first and second doped silicon regions, a combination of said first and second doped silicon regions with the interposed relatively thin dielectric layer defining an active region of an electro-optic device; a voltage bias applied across the at least one SISCAP optical waveguiding device to create a predetermined, constant capacitance value across the at least one SISCAP optical waveguiding device, thereby forming a linear operating region for the analog optical modulator; and an input RF electrical signal coupled to the second silicon region of the at least one SISCAP device, wherein the application of said input RF electrical signal, in combination with the voltage bias, modifies a phase of an optical signal passing therethrough to create a modulated analog optical output signal along the optical output waveguide, the modulated analog optical output signal replicating the input RF electrical signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An integrated optical communication system formed within an SOI structure comprising a silicon substrate, an overlying insulating layer and a relatively thin surface silicon waveguiding layer, the integrated optical communication system comprising
an analog optical modulator including an optical interferometer formed within the relatively thin silicon surface waveguiding layer, the interferometer including an input optical waveguide, a pair of parallel waveguiding arms and an output optical waveguide, with an input Y-splitter disposed between the input optical waveguide and an input to the pair of parallel waveguiding arms and an output Y-combiner disposed between an output of the pair of parallel waveguiding arms and the output optical waveguide, a continuous wave (CW) optical input signal coupled into the input optical waveguide; - and
at least one silicon-insulator-silicon capacitance (SISCAP) optical waveguiding device disposed in at least one of said pair of parallel waveguiding arms, the SISCAP optical waveguiding device comprising a first silicon region within the relatively thin silicon surface waveguiding layer doped to exhibit a first conductivity type; a second silicon region disposed to overlap, in part, the first silicon region, the second silicon region doped to exhibit a second, opposite conductivity type; a relatively thin dielectric layer disposed in an overlap area between said first and second doped silicon regions, a combination of said first and second doped silicon regions with the interposed relatively thin dielectric layer defining an active region of an electro-optic device; a voltage bias applied across the at least one SISCAP optical waveguiding device to create a predetermined, constant capacitance value across the at least one SISCAP optical waveguiding device, thereby forming a linear operating region for the analog optical modulator; and an input RF electrical signal coupled to the second silicon region of the at least one SISCAP device, wherein the application of said input RF electrical signal, in combination with the voltage bias, modifies a phase of an optical signal passing therethrough to create a modulated analog optical output signal along the optical output waveguide, the modulated analog optical output signal replicating the input RF electrical signal; and at least one optical component integrated within the SOI structure with the analog modulator; and at least one electrical component integrated within the SOI structure with the analog modulator. - View Dependent Claims (9, 10, 11)
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12. A silicon-based arrangement integrated within a single SOI structure, comprising a silicon substrate, an overlying insulating layer and a relatively thin surface silicon layer, the arrangement comprising
a plurality of N analog optical modulators interconnected in a predetermined array configuration, each analog modulator comprising: -
an optical interferometer formed within the relatively thin silicon surface waveguiding layer, the interferometer including an input optical waveguide, a pair of parallel waveguiding arms and an output optical waveguide, with an input Y-splitter disposed between the input optical waveguide and an input to the pair of parallel waveguiding arms and an output Y-combiner disposed between an output of the pair of parallel waveguiding arms and the output optical waveguide, a continuous wave (CW) optical input signal coupled into the input optical waveguide; and at least one silicon-insulator-silicon capacitance (SISCAP) optical waveguiding device disposed in at least one of said pair of parallel waveguiding arms, the SISCAP optical waveguiding device comprising a first silicon region within the relatively thin silicon surface waveguiding layer doped to exhibit a first conductivity type; a second silicon region disposed to overlap, in part, the first silicon region, the second silicon region doped to exhibit a second, opposite conductivity type; a relatively thin dielectric layer disposed in an overlap area between said first and second doped silicon regions, a combination of said first and second doped silicon regions with the interposed relatively thin dielectric layer defining an active region of an electro-optic device; a voltage bias applied across the at least one SISCAP optical waveguiding device to create a predetermined, constant capacitance value across the at least one SISCAP optical waveguiding device, thereby forming a linear operating region for the analog optical modulator; and an input RF electrical signal coupled to the second silicon region of the at least one SISCAP device, wherein the application of said input RF electrical signal, in combination with the voltage bias, modifies a phase of an optical signal passing therethrough to create a modulated analog optical output signal along the optical output waveguide, the modulated analog optical output signal replicating the input RF electrical signal; and a plurality of optical waveguides, formed within the relatively thin silicon surface layer and arranged to form connections among the plurality of N analog optical modulators. - View Dependent Claims (13, 14)
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Specification