Waveguide-based sensor

Inventors

Heideman, Rene Gerrit

Assignees

LioniX International BV

Abstract

A sensor for sensing a target chemical with high signal-to-noise ratio is disclosed. In some embodiments, the sensor comprises a sensing region that is optically coupled with an attenuation region. The sensing region receives optical stimulation that comprises light characterized by an excitation wavelength. In response to exposure to the target chemical, the sensing region fluoresces at a fluorescence wavelength. The attenuation region receives light from the fluorescing sensing region that includes light characterized by the fluorescence wavelength (i.e., signal) and light characterized by the excitation wavelength (i.e., noise). The attenuation region conveys the light to a detector that provides an electrical output signal based on the target chemical. While conveying the light, however, the attenuation region improves the signal-to-noise ratio by attenuating light characterized by the excitation wavelength more than light characterized by the fluorescence region.

Core Innovation

The invention provides a fluorescence chemical sensor implemented with optical waveguides on a planar lightwave circuit (PLC). The sensor includes a sensing region and an in-line attenuation region in which excitation-wavelength light is attenuated more than fluorescence-wavelength light, improving signal-to-noise ratio (SNR) while both types of light propagate in the PLC. The sensing region produces a fluorescence signal characterized by a fluorescence wavelength when exposed to a target chemical and excitation light characterized by an excitation wavelength.

The attenuation region improves selectivity by coupling excitation-wavelength light using resonant element structures. The attenuation region includes a resonant element having a resonance at the excitation wavelength, where the resonant element couples light characterized by the excitation wavelength from one waveguide portion into another waveguide portion to remove or redirect the excitation light away from detection. This excitation-selective coupling is used to attenuate excitation light more than the fluorescence signal.

Different attenuation implementations are described, including wavelength-selective absorbing dye with cladding thinning to increase interaction length, shaped waveguide sections including spiral waveguide sections to extend dye interaction length, and resonant elements such as a racetrack ring resonator tuned to the excitation wavelength. The disclosure also describes embodiments including multi-sensor configurations, two-dimensional sensor arrays, and monolithic integration where a plurality of sensing regions are arranged in a two-dimensional arrangement and each sensing region is optically coupled to a corresponding attenuation region.

Claims Coverage

The document provides three independent claim sets for sensor structures and a sensing method that share a common inventive concept: an attenuation region that selectively couples excitation-wavelength light based on resonant element resonance, while allowing fluorescence-wavelength light to proceed to detection. Across the independent claims, the main inventive features cover selective attenuation by resonant coupling, waveguide portion partitioning in sensing and attenuation regions, and two-dimensional multi-region sensor arrangements.

Across the independent claims, the inventive concept is implemented by optical waveguide-coupled sensing regions that generate fluorescence signals upon exposure to a target chemical and excitation light, and attenuation regions that selectively attenuate excitation-wavelength light more than fluorescence-wavelength light via excitation-resonant coupling into additional waveguide portions. The multi-region independent claim further extends this architecture to a substrate with multiple sensing and attenuation regions arranged in a two-dimensional arrangement.

Stated Advantages

Documented Applications