SYSTEM AND METHODS FOR HIGHLY INTEGRATED OPTICAL READOUT MEMS SENSORS

• US 20160320180A1
• Filed: 05/26/2015
• Published: 11/03/2016
• Est. Priority Date: 04/29/2015
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Lodden, Grant H., Horning, Robert D.
• Granted Patent: US 10,024,656 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/0228 Inertial sensors
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 2201/04 Optical MEMS
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81B 2203/053 Translation according to an axis perpendicular to the substrate
• CPC Class Codes: B81B 7/0087 On-device systems and sensors for controlling, regulating or monitoring
• CPC Class Codes: G01B 11/272 using photoelectric detection means
• CPC Class Codes: G01C 19/5621 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/5656 the devices involving a micromechanical structure
• CPC Class Codes: G01C 25/00 Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass testing, calibrating or compensating compasses G01C17/38
• CPC Class Codes: G01P 15/093 by photoelectric pick-up
• CPC Class Codes: G01P 15/13 by measuring the force required to restore a proofmass subjected to inertial forces to a null position
• CPC Class Codes: G01P 2015/0822 for defining out-of-plane movement of the mass
• CPC Class Codes: G01P 21/00 Testing or calibrating of apparatus or devices covered by the preceding groups
• CPC Class Codes: G02B 2006/12138 Sensor
• CPC Class Codes: G02B 6/12 of the integrated circuit kind electric integrated circuits H01L27/00
• CPC Class Codes: G02B 6/4295 coupling with semiconductor devices activated by light through the light guide, e.g. thyristors, phototransistors
• CPC Class Codes: G02B 6/43 Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections

Abstract

System and methods for highly integrated optical readout MEMS sensors are provided. In one embodiment, a method for an integrated waveguide optical-pickoff sensor comprises: launching a laser beam generated by a laser light source into an integrated waveguide optical-pickoff monolithically fabricated within a first substrate, the integrated waveguide optical-pickoff including an optical input port, a coupling port, and an optical output port; and detecting an amount of coupling of the laser beam from the coupling port to a sensor component separated from the coupling port by a gap by measuring an attenuation of the laser beam at the optical output port.

Claims

1. A method for an integrated waveguide optical-pickoff sensor, the method comprising:

launching a laser beam generated by a laser light source into an integrated waveguide optical-pickoff monolithically fabricated within a first substrate, the integrated waveguide optical-pickoff including an optical input port, a coupling port, and an optical output port; and

detecting an amount of coupling of the laser beam from the coupling port to a sensor component separated from the coupling port by a gap by measuring an attenuation of the laser beam at the optical output port.

2. The method of claim 1, wherein the sensor component is a static structure, the method further comprising:

determining a drift in the laser beam as generated by the laser light source as a function of the attenuation of the laser beam at the optical output port due to coupling of the laser beam into the static structure.

3. The method of claim 2, further comprising:

correcting an inertial sensor measurement based on the attenuation of the laser beam, wherein the inertial sensor measurement was obtained from a second integrated waveguide optical-pickoff coupled to the laser light source.

4. The method of claim 1, wherein the sensor component is a moving sensor component.

5. The method of claim 4, wherein the moving sensor component is a micro-electromechanical system (MEMS) inertial sensor proof mass.

6. The method of claim 5, further comprising:

outputting an inertial acceleration measurement based on change in the attenuation of the laser beam at the optical output port due to a displacement of the MEMS inertial sensor proof mass.

7. The method of claim 1, wherein measuring an attenuation of the laser beam at the optical output port further comprises:

measuring the attenuation using a photodetector coupled to the optical output port; and

processing an electrical output of the photodetector.

8. The method of claim 1, wherein launching a laser beam generated by a laser light source further comprises:

launching the laser beam generated by the laser light source into at least a second integrated waveguide optical-pickoff monolithically fabricated within a second substrate, the second integrated waveguide optical-pickoff including a second coupling port, and a second optical output port; and

detecting an amount of coupling of the laser beam from the second coupling port to a second sensor component separated from the second coupling port by a second gap by measuring an attenuation of the laser beam at the second optical output port.

9. The method of claim 8, wherein the sensor component is a micro-electromechanical system (MEMS) inertial sensor proof mass, and the second sensor component is a second MEMS inertial sensor proof mass.

10. The method of claim 1, wherein the laser light source is fabricated within an interposer layer adjacent to the first substrate.

11. The method of claim 1, wherein the laser light source is a light-emitting diode (LED).

12. An integrated optical read out sensor, the sensor comprising:

at least a first glass substrate;

an integrated waveguide optical-pickoff monolithically fabricated within the first substrate and comprising an optical input port, a coupling port, and an optical output port;

a moving sensor component adjacent to the coupling port and having a degree-of-freedom of motion in a direction perpendicular to the coupling port of the integrated waveguide;

a laser light source that launches light into the first glass substrate via the optical input port, wherein a portion of the light couples from the coupling port to the moving sensor component as a function of a gap distance between the coupling port and the moving sensor component;

at least one photodetector coupled to the optical output port; and

electronics coupled to the at least one photodetector that calculates a measurement based on an attenuation of optical intensity of the light exiting from the optical output port, wherein the attenuation is at least in part a function of the gap distance.

13. The sensor of claim 12, wherein the moving sensor component is a micro-electromechanical system (MEMS) inertial sensor proof mass.

14. The sensor of claim 12, wherein the laser light source is fabricated within an interposer layer adjacent to the first substrate.

15. The sensor of claim 12, further comprising:

an integrated waveguide optical pickoff drift sensor coupled to the laser light source, the integrated waveguide optical pickoff drift sensor comprising;

a second coupling port, and a second optical output port;

a static structure separated from the second optical output port by a second gap having a fixed distance;

a second photodetector coupled to the second optical output port;

wherein a portion of the light couples from the second coupling port across the second gap to the static structure.

16. The sensor of claim 15, further comprising:

a drift error calculator coupled to the second photodetector, wherein the drift error calculator calculates an error based on an attenuation of optical intensity of the light exiting from the second optical output port.

17. The sensor of claim 16, wherein the electronics calibrates the measurement based on the drift error.

18. The sensor of claim 12, further comprising:

a second glass substrate;

a second integrated waveguide optical-pickoff monolithically fabricated within the second substrate and comprising a second coupling port, and a second optical output port;

a second moving sensor component adjacent to the second coupling port and having a degree-of-freedom of motion in a direction perpendicular to the second coupling port;

wherein the laser light source further launches light into the second glass substrate, wherein a portion of the light couples from the second coupling port to the second moving sensor component as a function of a second gap distance between the second coupling port and the second moving sensor component.

19. The sensor of claim 18, the electronics further coupled to the second photodetector, wherein the electronics further calculates the measurement based on attenuation of optical intensity of the light exiting from the second optical output port, wherein the attenuation of optical intensity of the light exiting from the second optical output port is at least in part a function of the second gap distance.

20. The sensor of claim 12, wherein the laser light source is a light-emitting diode (LED).