High speed and low loss GeSi/Si electro-absorption light modulator and method of fabrication using selective growth
AssigneeMassachusetts Institute of Technology
InventorsDong Pan, Jifeng Liu, Jurgen Michel, Lionel C. Kimerling
Life of this patent
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Abstract
An optoelectronic device includes an input waveguide structure that receives an input optical signal. A GeSi/Si waveguide structure receives from the input waveguide the input optical signal and performs selective optoelectronic operations on the input optical signal. The GeSi/Si waveguide structure outputs an optical or electrical output signal associated with the selective optoelectronic operations performed on the input optical signal. An output waveguide structure receives the output optical signal from the GeSi/Si waveguide structure and provides the optical output signal for further processing.
Claims17
An optoelectronic device on Si or SOT wafer comprising:
- a substrate;
- an on-chip input waveguide structure that receives an input optical signal;
- a GeSi/Si waveguide structure having a GeSi absorption region which is in contact with and directly butt-coupled to said on-chip input waveguide, said GeSi/Si waveguide structure receives the input optical signal and performs optical modulation at reverse bias on the input optical signal based on Franz-Keldysh effect, the GeSi/Si waveguide structure outputs an output optical signal associated with the optical modulation operations performed on said input optical signal;
- an on-chip output waveguide structure that is directly butt-coupled to and in contact with said GeSi absorption region, receives the output optical signal and provides said optical output signal for further processing, said on-chip input waveguide structure and said on-chip output waveguide structure each having a first dielectric layer, said first dielectric layers being directly positioned on said substrate, said on-chip input waveguide structure and said on-chip output waveguide structure each comprising a core being directly positioned on said first dielectric layers and a second dielectric layer being directly positioned on said on-chip input waveguide structure and said on-chip output waveguide structure;
- and
- a first doped semiconductor layer having a selective doping type positioned on the GeSi absorption region and a second doped semiconductor layer positioned on another side of said GeSi absorption region having an opposite doping type from said selective doping type to allow electric fields to be applied to the GeSi absorption region at reverse bias;
- wherein
- said first doped semiconductor layer being directly positioned on said substrate, said GeSi absorption region being directly positioned on said first doped semiconductor layer and said second semiconductor layer being directly positioned on said GeSi absorption region.
A method of forming an optoelectronic device comprising:
- providing a substrate,
- forming on said substrate an on-chip input waveguide structure that receives an input optical signal;
- forming a GeSi/Si waveguide structure having a GeSi absorption region which is in contact with and directly butt-coupled to said on-chip input waveguide, said GeSi/Si waveguide structure receives the input optical signal and performs optical modulation at reverse bias on the input optical signal based on Franz-Keldysh effect, the GeSi/Si waveguide structure outputs an output optical signal associated with the optical modulation operations performed on said input optical signal;
- forming an on-chip output waveguide structure that is directly butt-coupled to and in contact with said GeSi absorption region the output waveguide structure receives said output optical signal, and provides said output optical signal for further processing, said on-chip input waveguide structure and said on-chip output waveguide structure each having a first dielectric layer, said first dielectric layers being directly positioned on said substrate, said on-chip input waveguide structure and said on-chip output waveguide structure each comprising a core being directly positioned on said first dielectric layers and a second dielectric layer being directly positioned on said on-chip input waveguide structure and said on-chip output waveguide structure;
- and
- forming a first doped semiconductor layer having a selective doping type positioned on the GeSi absorption region and a second doped semiconductor layer positioned on another side of said GeSi absorption region having an opposite doping type from said selective doping type to allow electric fields to be applied to the GeSi absorption region at reverse bias;
- wherein
- said first doped semiconductor layer being directly positioned on said substrate, said GeSi absorption region being directly positioned on said first doped semiconductor layer and said second semiconductor layer being directly positioned on said GeSi absorption region.
A monolithically integrated optoelectronic circuit on Si or SOI wafer comprising:
- an on-chip input waveguide structure that transmits an input optical signal;
- a GeSi/Si waveguide structure, said GeSi/Si waveguide structure has a GeSi absorption region which is directly butt-coupled to said on-chip input waveguide;
- said GeSi/Si waveguide structure receives the input optical signal and performs optical modulation at reverse bias on the input optical signal based on Franz-Keldysh effect;
- an on chip output waveguide structure that is directly butt-coupled to and in contact with said GeSi absorption region that receives the modulated optical signal from said GeSi/Si waveguide structure and transfers said modulated optical signals for further processing, said on-chip input waveguide structure and said on-chip output waveguide structure each having a first dielectric layer, said first dielectric layers being directly positioned on said substrate, said on-chip input waveguide structure and said on-chip output waveguide structure each comprising a core being directly positioned on said first dielectric layers and a second dielectric layer being directly positioned on said on-chip input waveguide structure and said on-chip output waveguide structure;
- a first doped semiconductor layer having a selective doping type positioned on the GeSi absorption region and a second doped semiconductor layer positioned on another side of said GeSi absorption region having an opposite doping type from said selective doping type to allow electric fields to be applied to the GeSi absorption region at reverse bias, said first doped semiconductor layer being directly positioned on said substrate, said GeSi absorption region being directly positioned on said first doped semiconductor layer and said second semiconductor layer being directly positioned on said GeSi absorption region;
- an optoelectronic function module that receives the modulated optical signals from said output waveguide structure and performs optoelectronic functions;
- and
- a second GeSi/Si waveguide structure with the same GeSi composition and device structure as said first GeSi/Si waveguide structure that receives the optical signal from said optoelectronic function module via butt-coupling and outputs said optical signal for further processing.
Dependencies are inferred from the claim text.