Massachusetts Institute of Technology

Danhao Ma

Anuradha Murthy Agarwal

Brian W Anthony

Robin Singh

Peter X Su

Jurgen Michel

Yiding Lin

A photonic aerosol particle sensor includes a microfluidic sensor chamber in which is disposed a plurality of photonic waveguide resonators each having a photonic waveguide on an underlying substrate, along a separate waveguide resonator path with a lateral width different than that of other photonic waveguide resonators. All waveguides in the plurality have a common vertical thickness of a common waveguide material having a refractive index that is larger than that of the underlying substrate material. An optical input connection couples light into the waveguide resonators. An aerosol particle input fluidically connected to the microfluidic chamber fluidically conveys aerosol particles to the chamber, and an aerosol particle output fluidically connected to the microfluidic chamber fluidically conveys aerosol particles out of the chamber. At least one optical output connection accepts light out of the plurality of photonic waveguide resonators to provide a signal indicative of at least one aerosol particle characteristic.

Physical and chemical characterization of aerosols with photonic waveguides

A photonic aerosol particle sensor includes a plurality of photonic waveguide resonators each having a photonic waveguide disposed along a separate waveguide resonator path and each photonic waveguide having a lateral waveguide width different than the waveguide width of other photonic waveguide resonators in the plurality. All waveguides in the plurality of photonic waveguide resonators have a common vertical thickness and are formed of a common photonic waveguide material. An optical input connection couples light into the waveguide resonators. A particle input conveys aerosol particles toward the waveguide resonators and an aerosol particle output conveys aerosol particles away from the waveguide resonators. At least one optical output connection is optically connected to accept light out of the plurality of photonic waveguide resonators to provide a signal indicative of at least one characteristic of the aerosol particles to be analyzed.

An integrated optical modulator array useful for modulating light at different wavelengths in the same optical band includes multiple GeSi waveguides on a substrate. Each GeSi waveguide has a different width and is coupled to electrodes to form an electro-absorption modulator. A stressor material, such as SiN, disposed between the GeSi waveguides in the optical modulators applies a strain to the GeSi waveguides. Because each GeSi waveguide has a different width, it experiences a different strain. This difference can be a difference in magnitude, type (homogeneous v. inhomogeneous, compressive v. tensile), or both. The different strains shift the bandgaps of the Ge in the GeSi waveguides by different amounts, shifting the optical absorption edges for the GeSi waveguides by different amounts. Put differently, the stressor layer strains each GeSi modulator differently, causing each GeSi modulator to operate at a different wavelength.

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Danhao Ma