Silicon photonic waveguide biosensor configurations

Abstract

Methods and devices relating to sensors and sensor blocks for use in detecting and monitoring molecular interactions. A silicon waveguide sensing element is provided along with a layer of silicon. A silicon oxide layer is also provided between the waveguide element and the layer of silicon. The sensing element is adjacent to an aqueous solution in which the molecular interactions are occurring. A light beam travelling in the silicon waveguide creates an evanescent optical field on the surface of the sensing element adjacent to the boundary between the sensing element and the aqueous medium. Molecular interactions occurring on this surface affect the intensity or the phase of the light beam travelling through the waveguide by changing the effective refractive index of the medium. By measuring the effect on the intensity, phase, or speed of the light beam, the molecular interactions can be detected and monitored in real time. Various configurations using this sensor technology is also disclosed.

1 . An optical sensor block for use in detecting molecules in a liquid or gas medium, the sensor block comprising:
 a group of sensors comprising at least two sensor elements wherein each sensor element comprises
 a substrate layer 
 a light waveguide sensor adjacent said medium 
 a lower cladding layer between said waveguide sensor and said substrate layer 
 wherein 
 molecular interactions at the waveguide sensor surface affect at least one characteristic of light travelling through said waveguide sensor 
 light travelling through said waveguide sensor is for eventual reception by an optical detector. 
   
   
   
       2 . An optical sensor block according to  claim 1  wherein said sensor block has a single optical input and said sensor block further comprises an optical signal splitting means. 
   
   
       3 . An optical sensor block according to  claim 1  wherein said sensor block has a plurality of optical inputs. 
   
   
       4 . An optical sensor block according to  claim 3 , wherein said plurality of optical inputs are coupled to said sensors through an array of vertical waveguide couplers. 
   
   
       5 . An optical sensor block according to  claim 4 , wherein at least one of said array of vertical waveguide couplers is a diffraction grating. 
   
   
       6 . An optical sensor block according to  claim 4  wherein at least one of said array of vertical waveguide couplers is a 45 degree mirror. 
   
   
       7 . An optical sensor block according to  claim 2  wherein said optical splitting means is an optical splitter for splitting said single optical input between said at least two sensor elements in said group. 
   
   
       8 . An optical sensor block according to  claim 2  wherein said optical splitting device is an optical demultiplexer for demultiplexing said single optical input between said at least two sensor elements in said group. 
   
   
       9 . An optical sensor block according to  claim 1  wherein at least one sensor element in said sensor block is configured as an optical ring resonator such that for said at least one sensor element, said light waveguide sensor is configured as a ring. 
   
   
       10 . An optical sensor block according to  claim 1  wherein at least one sensor element in said sensor block is configured as a two-mirror resonator, such that for said at least one sensor element, said light waveguide sensor is in a waveguide resonator cavity formed between two mirrors. 
   
   
       11 . A sensor block according to  claim 1  wherein at least one sensor element in said sensor block is configured as a spiral such that for said at least one sensor element, said light waveguide sensor adjacent said medium is arranged as a spiral. 
   
   
       12 . A sensor block according to  claim 1  wherein at least one sensor element in said sensor block has said light waveguide sensor arranged and configured as a single weft weaving pattern with each trace of said pattern being parallel to other traces to result in a grid-like pattern of parallel lines adjacent said medium 
   
   
       13 . A sensor block according to  claim 1  wherein at least one sensor element in said sensor block comprises waveguide sections with different dn/dT characteristics for reducing sensor temperature sensitivity. 
   
   
       14 . A sensor block according to  claim 9  wherein the or each of said at least one sensor element is configured as a ring resonator and has a specific resonance wavelength such that an input beam having said specific wavelength passes through said ring resonator. 
   
   
       15 . An optical sensor block for use in detecting molecules in a liquid or gas medium, the sensor block comprising:
 a Mach-Zehnder interferometer having a first and a second arm, said first arm being a sensor arm having an optical sensor element, said optical sensor element comprising:
 a substrate layer 
 a light waveguide sensor adjacent said medium 
 a lower cladding layer between said waveguide sensor and said substrate layer 
 wherein 
   molecular interactions at the waveguide sensor surface affect at least one characteristic of light travelling through said waveguide sensor   light travelling through said waveguide sensor is for eventual reception by an optical detector.   
   
   
       16 . An optical sensor block according to  claim 15  wherein said optical sensor element is configured as a ring resonator with said light waveguide sensor being configured as a ring. 
   
   
       17 . An optical sensor block according to  claim 15  wherein said second arm is a reference arm having a modulator. 
   
   
       18 - 21 . (canceled) 
   
   
       22 . A sensor for use in detecting molecules in a liquid or gas medium, the sensor comprising:
 a substrate layer,   a light waveguide sensor element adjacent said medium   a lower cladding layer between said sensor element and said substrate layer   wherein   molecular interactions at the waveguide surface affect at least one characteristic of light travelling through said waveguide sensor element   and wherein said sensor element is configured as one arm of a Mach-Zehnder interferometer.   
   
   
       23 . A sensor according to  claim 22  wherein said sensor element comprises a thin, high refractive index contrast waveguide. 
   
   
       24 . A sensor according to  claim 22  wherein said sensor element comprises a silicon photonic waveguide. 
   
   
       25 . A sensor according to  claim 22  wherein said lower cladding layer comprises a layer of silicon oxide.