Energy system monitoring

Patent metadata

Field	Value
Publication number	US-2016018319-A1
Application number	US-201414331318-A
Country	US
Kind code	A1
Filing date	Jul 15, 2014
Priority date	Jul 15, 2014
Publication date	Jan 21, 2016
Grant date	—

Abstract

An optical coupler includes at least one input waveguide and a plurality of output waveguides. The optical coupler spatially disperses optical signals carried on the input waveguide according to wavelength to the output waveguides. The input waveguides and the output waveguides are arranged to provide crosstalk between optical signals carried on the output waveguides.

First claim

1 . A monitoring system for an energy system, comprising:
N>1 optical sensors, each optical sensor operating within a different wavelength range and emanating output light in response to input light, the output light having a centroid wavelength that changes in response to a sensed parameter of the energy system; a plurality of photodetectors, each photodetector configured to generate an electrical signal in response to light incident on a light sensitive surface of the photodetector; and an optical coupler including at least one input waveguide configured to receive light from the optical sensors and a plurality of output waveguides, the optical coupler configured to disperse light from the input waveguide to the output waveguides according to wavelength of light so that sensor output light emanating from each optical sensor is optically coupled through at least one output waveguide to at least one photodetector, wherein the electrical signal generated by the photodetector in response to the sensor output light provides information about the sensed parameter of the energy system.

2 . The system of claim 1 , wherein the optical coupler comprises an arrayed waveguide grating.

3 . The system of claim 1 , wherein the optical coupler comprises a linear variable filter.

4 . The system of claim 1 , wherein:
the plurality of output waveguides comprises N pairs of output waveguides; the plurality of photodetectors comprises N pairs of photodetectors; and the optical coupler is configured to spatially disperse light from the input waveguide according to wavelength so that the output light emanating from each optical sensor is optically coupled to a pair of photodetectors through a pair of adjacent output waveguides and the output waveguides in the pair are arranged and configured to allow crosstalk between the pair output waveguides.

5 . The system of claim 4 , wherein the N pairs of output waveguides are configured so that the crosstalk between the output waveguides of the pair of output waveguides is greater than crosstalk between either of the output waveguides of the pair and a waveguide of an adjacent pair.

6 . The system of claim 4 , wherein the output waveguides are adjacent and tha center-to-center spacing between the adjacent output waveguides in the pair of output waveguides is on the order of a full width half maximum intensity (FWHM) optical spot size at an input of the output waveguides.

7 . The system of claim 6 , wherein the spacing is between about ⅕ and about 5 times the FWHM optical spot size at the input of the output waveguides.

8 . The system of claim 6 , wherein the spacing is between about ½ and about 2 times the FWHM optical spot size at the input of the output waveguides.

9 . The system of claim 1 , wherein the optical coupler comprises an arrayed waveguide grating including K array waveguides optically coupled to the input waveguide, wherein K is chosen according to the formula

λ

m



Δλ

≤
K
≤

4

λ

m



Δλ

,

Δλ is an expected operational range of the sensor with a center wavelength λ, and m is a diffraction order of the AWG.

10 . The system of claim 1 , wherein optical coupler comprises an arrayed waveguide grating including K array waveguides optically coupled to the input waveguide, the K array waveguides spaced a distance d apart, each array waveguide arranged a distance f from an input of an output waveguide, wherein a spacing between a pair of adjacent output waveguides is less than 2fλ/Kd.

11 . The system of claim 1 , wherein the optical coupler comprises an arrayed waveguide grating including K array waveguides optically coupled to the input waveguide and wherein inputs of the output waveguides are positioned away from focal points of the array waveguides.

12 . The system of claim 1 , wherein the optical demultiplexer comprises at least one additional optically dispersive element between the optical coupler and the photodetectors.

13 . The system of claim 1 , wherein the optical coupler comprises an arrayed waveguide grating having at least N output waveguides, each output waveguide having a wavelength pass-band at least equal to a range of an expected spectral shift of output light of an associated optical sensor.

14 . The system of claim 1 , wherein:
the photodetectors comprise 2N pairs of photodetectors, each photodetector pair including a first and a second photodetector, the first photodetector configured to generate a current, I 1 , in response to light incident on the light sensitive surface of the first photodetector and a second photodetector configured to generate a current, I 2 , in response to light incident on the light sensitive surface of the second photodetector, and wherein a change in the sensed parameter causes a change in a ratio between I 1 to I 2 .

15 . The system of claim 1 , further comprising processor circuitry configured to perform an estimation routine using the electrical signals to locate centroids of output light emanating from the N sensors.

16 . The system of claim 1 , wherein the N optical sensors are arranged along a single sensor waveguide.

17 . The system of claim 1 , wherein the N optical sensors are disposed on multiple sensor waveguides, and further comprising an optical multiplexer optically coupled between the multiple sensor waveguides and the input waveguide.

18 . The system of claim 17 , wherein the optical multiplexer comprises a time division multiplexer, the time domain multiplexer comprising at least one of:
a set of M optical switches; and a single 1×M optical switch.

19 . The system of claim 17 , wherein the optical multiplexer comprises a wavelength division multiplexer.

20 . The system of claim 1 , wherein the N optical sensors are disposed on N sensor waveguides, and further comprising N optical circulators, each of the N sensor waveguides respectively optically coupled to the input waveguide through one of the N optical circulators.

21 . The system of claim 1 , wherein the energy device is a battery.

22 . The system of claim 1 , wherein the photodetectors and optical coupler are arranged on a wafer as an integrated electro-optical subsystem.

23 . A monitoring system, comprising:
M optical monitoring modules, each optical monitoring module comprising N>1 optical sensors, each optical sensor emanating sensor output light having a centroid wavelength that changes in response to a sensed parameter; a plurality of photodetectors, each photodetector configured to generate an electrical output signal in response to light incident on a light sensitive surface of the photodetector; a time domain optical multiplexer; and a wavelength domain optical demultiplexer optically coup

Assignees

• Palo Alto Res Ct Inc

Inventors

• Hegyi Alex
• Kiesel Peter
• Raghavan Ajay

Classifications

• G01N2201/088

  Using a sensor fibre · CPC title

• G01N2201/061

  Sources · CPC title

• G01N2201/068

  Optics, miscellaneous · CPC title

• G02B6/2938

  for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM · CPC title

• G02B6/12009

  comprising arrayed waveguide grating [AWG] devices, i.e. with a phased array of waveguides · CPC title