PHOTONIC CRYSTAL FIBER SENSOR

• US 20100284020A1
• Filed: 05/08/2009
• Published: 11/11/2010
• Est. Priority Date: 05/08/2009
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Sanders, Glen A.
• Granted Patent: US 7,952,772 B2
• Time in Patent Office: Days
• US Class Current: 356/480
• CPC Class Codes: G01N 2021/7766 Capillary fill
• CPC Class Codes: G01N 2021/7789 Cavity or resonator
• CPC Class Codes: G01N 21/39 using tunable lasers
• CPC Class Codes: G01N 21/7746 the waveguide coupled to a cavity resonator
• CPC Class Codes: G02B 6/02366 Single ring of structures, e.g. "air clad"
• CPC Class Codes: G02B 6/02385 Comprising liquid, e.g. fluid filled holes

Abstract

Apparatus and method for chemical and biological agent sensing. An example sensing apparatus includes a resonator having a resonance frequency. The resonator includes a coil of a photonic crystal fiber. The photonic crystal fiber has a solid region configured to guide a substantially single optical mode of light having, a cladding surrounding an exterior of the solid region, and at least one hollow core within the cladding. The cladding contains at least one hollow core. The photonic crystal fiber is configured to introduce a fluid that may contain an analyte to the hollow core. The photonic crystal fiber is configured so that the light interacts with the fluid. The resonator is configured to produce a resonance signal centered at the resonance frequency. A predetermined change in the resonance signal indicates a presence of a quantity of the analyte in the fluid.

Claims

1. A photonic crystal fiber resonator comprising:

a solid region; and

a cladding surrounding an exterior of the solid region, the cladding comprising at least one hollow channel configured to receive a fluid from an external source, the fluid may contain a quantity of an analyte,

wherein the photonic crystal fiber has a coil section having at least one turn, the photonic crystal fiber has two ends configured to be in optical communication with each other, the solid region is configured to guide a substantially single optical mode of light that extends into the at least one hollow channel containing the fluid, the photonic crystal fiber resonator is configured to pass the substantially single optical mode of light through the at least one hollow channel containing the fluid multiple times, the photonic crystal fiber resonator is configured to resonate a first resonance signal when the substantially single optical mode of light is frequency-scanned through a region about a resonance frequency if a measurable quantity of the analyte absent from the fluid and resonate a second resonance signal other than the first resonance signal when the substantially single optical mode of light is frequency-scanned through the region about the resonance frequency if the measurable quantity of the analyte is present in the fluid.

2. The photonic crystal fiber resonator of claim 1, wherein the coil section has about 20 to about 40 turns.

3. The photonic crystal fiber resonator of claim 1, wherein the coil encircles an area having a diameter of about 1 cm.

4. The photonic crystal fiber resonator of claim 1, wherein the cladding comprises three hollow channels.

5. The photonic crystal fiber resonator of claim 1, wherein the cladding has a refractive index greater than the refractive index of both the hollow channels and the fluid, and wherein a position of the hollow channels is selected to extend a portion of an evanescent tail of the substantially single optical mode of light into the at least one hollow channel.

6. The photonic crystal fiber resonator of claim 1, wherein the photonic crystal fiber further comprises an input and an output, the input and the output are configured to pass the fluid that may contain the analyte through a substantial portion of the at least one hollow channel.

7. The photonic crystal fiber of claim 6, wherein the input and the output are configured to apply a pressure differential to the at least one hollow core in order to pass the fluid there through.

8. The photonic crystal fiber resonator of claim 1, wherein the photonic crystal fiber further comprises a plurality of holes extending from an exterior of the photonic crystal fiber into the at least one hollow channel, the plurality of holes configured to pass the fluid that may contain a measurable quantity of the analyte through a substantial portion of the at least one hollow channel.

9. A sensor for sensing an analyte, the sensor comprising:

a tunable light source configured to provide a substantially single optical mode of light;

a detector;

a processor; and

a resonator configured to resonate light of a predefined frequency, the resonator comprising a coil, the coil comprising a photonic crystal fiber, the photonic crystal fiber comprising;

a solid region configured to guide a substantially single optical mode of light, the substantially single optical mode of light passing through the coil multiple times; and

a cladding surrounding an exterior of the solid region, the cladding comprising at least one hollow channel configured to receive a fluid from an external source, the fluid may contain more than a measurable quantity of an analyte, a portion of the single optical mode of light extends into the at least one hollow channel configured to receive a fluid,

wherein the tunable light source is in optical communication with the detector and the resonator, the resonator is in optical communication with the detector, and the detector is in one of electrical or optical communication with the processor, and wherein the detector detects a resonance signal centered at the resonance frequency as the tunable light source is tuned through a region about the resonance frequency, a predetermined change in the resonance signal detected by the detector indicates the quantity of the analyte in the fluid.

10. The sensor of claim 9, wherein the photonic crystal fiber further comprises an input and an output, the input and the output configured to pass the fluid that may contain the analyte through a substantial portion of the at least one hollow channel.

11. The photonic crystal fiber of claim 10, wherein the input and the output are configured to apply a pressure differential to the at least one hollow channel.

12. The sensor of claim 9, wherein the photonic crystal fiber further comprises a plurality of holes extending from an exterior of the photonic crystal fiber into the at least one hollow channel, the plurality of holes configured to pass the fluid that may contain the analyte of interest through a substantial portion of the at least one hollow channel.

13. A method for sensing an analyte, the method comprising:

passing a fluid that may contain an analyte through at least a portion of at least one hollow channel of a photonic crystal fiber configured within a resonator;

propagating a light wave in a single optical mode through the resonator, wherein a portion of the light wave extends into the hollow channel containing the fluid; and

determining a quantity of the analyte that is present in the fluid based on a detected resonance signal.

14. The method of claim 13, further comprising determining a concentration of the analyte in the fluid based on the detected resonance signal, if the presence of the analyte in the fluid has been determined.

15. The method of claim 13, wherein passing further comprises applying a pressure differential to the at least one hollow channel of the photonic crystal fiber.

16. The method of claim 13, wherein passing further comprises the fluid diffusing into and out of the at least one hollow channel through holes extending from an exterior of the photonic crystal fiber into the at least one hollow channel.