Electronics, AFC, Phase I
Multilayer Waveguide Optical Gyroscope
Objective
Develop a high-end tactical miniature optical waveguide gyroscope that is low-cost and lightweight for future U.S. Army missions.
Description
The success of U.S. Army missions depends on personnel and platforms having access to accurate and reliable position, velocity, attitude, and time information. Army missions such as Long Range Precision Fires (LRPF), Next Generation Combat Vehicle (NGCV) and Future Vertical Lift (FVL) rely on inertial navigation systems to provide continuous position and velocity information for accurate navigation.
However, current inertial navigation systems are large and expensive to build and maintain. Currently available small-size gyros and Inertial Measurement Units (IMUs), such as Micro-Electro-Mechanical (MEMS)-based sensors, do not meet the Army requirements for cost, accuracy, long term stability, and superior survivability when exposed to extreme environmental shock and vibrations environments.
To meet these future mission requirements, the Army needs a low Size, Weight, Power, and Cost (SWaP-C) 6-axis IMU (3-axis accelerometer and 3-axis gyroscope) that has high-tactical performance. Achieving the desired accuracy in position, velocity, and attitude will require a gyro bias stability to be demonstrated at or better than 0.2 degrees/hour (1 sigma) over extended temperature range, scale factor error less than 50 ppm and ARW less than 0.05 degree/root-hour (max).
In addition, the gyroscope should have a high bandwidth (up to 10 kHz), high dynamic range (greater than 2000 deg/sec), and low sensitivity to extreme shock and vibration environments. The volume goal for the IMU is less than 8 cubic inches.
The goal of this solicitation is the demonstration of the feasibility of new optical waveguide gyroscope technologies that have the promise to meet these demanding criteria. One example of such a technology is the integrated Silicon waveguide Optical Gyroscope (iSOG) that is based on the recent demonstration of low-loss Silicon Nitride (SN) optical waveguides. There have been several demonstrations of iSOG technology using single layer short sensing coils that have been reported in the literature.
The sensitivity scaling of most waveguide optical gyro designs is approximately proportional to the length of waveguide times the mean diameter of the sensing waveguide loop. The size of a square waveguide optical chip is limited to 22-44 mm given the IMU volume constraint and the capability of existing SiN waveguide foundries. That size limits the mean diameter of the coil to about 30 mm. With such a diameter at least 80 to 100 meters of waveguide is required to achieve the sensitivity and bias stability goals, The required length leads to the conclusion that multiple waveguide layers need to be fabricated on the optical chip.
Phase I
Prove the feasibility of a multi-level waveguide optical sensor coil. Develop a two-layer waveguide sensor coil design and fabricate a prototype two-layer sensor coil optical chip. Demonstrate that a loss of less than 0.5 dB/m can be simultaneously achieved in both waveguide layers with less than 1 dB vertical coupling loss. Insert the sensor coil in a gyro test bed and measure the in-run bias stability and ARW. Develop a waveguide optical gyroscope design that will be prototyped in Phase II.
Phase II
Design and deliver a prototype waveguide optical gyroscope. The prototype will undergo an independent evaluation at AvMC test facilities to determine its ability to satisfy design performance parameters and its functionality in Army environments.
Phase III
The final form factor Inertial Sensor Assembly (ISA) consisting of three gyros and three accelerometers will be developed. The ISA design would be compatible with future IMU packaging, but the electronics and light source will be external. The tethered IMU will be integrated and tested.
Once this development is concluded, a final form factor IMU, either as integrated unit with miniaturized electronics, or as tethered ISA with remote electronics, could be developed based on the final user requirements/form factor. Commercial IMU applications of the new gyro components by partnering with an IMU vendor will be pursued along with Army autonomous modular payloads and other military applications for possible use of this new technology.
Submission Information
For more information, and to submit your full proposal package, visit the DSIP Portal.
SBIR|STTR Help Desk: usarmy.sbirsttr@army.mil
References:
- Lefèvre, H. C. Fundamentals of the interferometric fiber-optic gyroscope. Opt. Rev. 4, 20–27 (1997).; G.A. Pavlath, “Fiber Optic Gyros:
- The Vision Realized,” 2006, Available at: http://www.nsd.es.northropgrumman.com/Html/Emerging-Technology-White-Papers/PDFs/Fiber-Optic_Gyros.pdf.;
- Jared F. Bauters, Martijn J. R. Heck, Demis D. John, Jonathon S. Barton, Christiaan M. Bruinink, Arne Leinse, René G. Heideman, Daniel J. Blumenthal, and John E. Bowers, “Planar waveguides with less than 0.1 dB/m propagation loss fabricated with wafer bonding,” Opt. Exp. 19, 24090 (2011).;
- Kuanping Shan, Shibnath Pathak, Binbin Guan, Guangyao Liu, and S.J.B. Yoo, “Low-loss compact multilayer silicon nitride platform for 3D photonic integrated circuits,” Opt Express 23(16), 21334-21342 (2015).;
- W.K. Bischel and L. Reichertz, “Mulitlayer Waveguide Optical Gyroscope,” US Patent 10852137 (2019).; Mike Horton, “Planar silicon nitride waveguide and silicon photonics integrated circuit for commercial optical gyroscope,” Proc. SPIE PC12105, Fiber Optic Sensors and Applications, XVIII, (13 June 2022); https://doi.org/10.1117/12.2617427.;
- Sudharsanan Srinivasan, Renan Moreira, Daniel Blumenthat and John E. Bowers, “Design of integrated hybrid silicon waveguide optical gyroscope,” Opt. Express 22 (21), 24988-24993 (2014).;
- Beibei Wu, Yu Yu, Jiabi Xiong and Xinliang Zhang, “Silicon Integrated Interferometric Optical Gyroscope,” Nature/Scientific Reports 8, 8766 (2018).
Objective
Develop a high-end tactical miniature optical waveguide gyroscope that is low-cost and lightweight for future U.S. Army missions.
Description
The success of U.S. Army missions depends on personnel and platforms having access to accurate and reliable position, velocity, attitude, and time information. Army missions such as Long Range Precision Fires (LRPF), Next Generation Combat Vehicle (NGCV) and Future Vertical Lift (FVL) rely on inertial navigation systems to provide continuous position and velocity information for accurate navigation.
However, current inertial navigation systems are large and expensive to build and maintain. Currently available small-size gyros and Inertial Measurement Units (IMUs), such as Micro-Electro-Mechanical (MEMS)-based sensors, do not meet the Army requirements for cost, accuracy, long term stability, and superior survivability when exposed to extreme environmental shock and vibrations environments.
To meet these future mission requirements, the Army needs a low Size, Weight, Power, and Cost (SWaP-C) 6-axis IMU (3-axis accelerometer and 3-axis gyroscope) that has high-tactical performance. Achieving the desired accuracy in position, velocity, and attitude will require a gyro bias stability to be demonstrated at or better than 0.2 degrees/hour (1 sigma) over extended temperature range, scale factor error less than 50 ppm and ARW less than 0.05 degree/root-hour (max).
In addition, the gyroscope should have a high bandwidth (up to 10 kHz), high dynamic range (greater than 2000 deg/sec), and low sensitivity to extreme shock and vibration environments. The volume goal for the IMU is less than 8 cubic inches.
The goal of this solicitation is the demonstration of the feasibility of new optical waveguide gyroscope technologies that have the promise to meet these demanding criteria. One example of such a technology is the integrated Silicon waveguide Optical Gyroscope (iSOG) that is based on the recent demonstration of low-loss Silicon Nitride (SN) optical waveguides. There have been several demonstrations of iSOG technology using single layer short sensing coils that have been reported in the literature.
The sensitivity scaling of most waveguide optical gyro designs is approximately proportional to the length of waveguide times the mean diameter of the sensing waveguide loop. The size of a square waveguide optical chip is limited to 22-44 mm given the IMU volume constraint and the capability of existing SiN waveguide foundries. That size limits the mean diameter of the coil to about 30 mm. With such a diameter at least 80 to 100 meters of waveguide is required to achieve the sensitivity and bias stability goals, The required length leads to the conclusion that multiple waveguide layers need to be fabricated on the optical chip.
Phase I
Prove the feasibility of a multi-level waveguide optical sensor coil. Develop a two-layer waveguide sensor coil design and fabricate a prototype two-layer sensor coil optical chip. Demonstrate that a loss of less than 0.5 dB/m can be simultaneously achieved in both waveguide layers with less than 1 dB vertical coupling loss. Insert the sensor coil in a gyro test bed and measure the in-run bias stability and ARW. Develop a waveguide optical gyroscope design that will be prototyped in Phase II.
Phase II
Design and deliver a prototype waveguide optical gyroscope. The prototype will undergo an independent evaluation at AvMC test facilities to determine its ability to satisfy design performance parameters and its functionality in Army environments.
Phase III
The final form factor Inertial Sensor Assembly (ISA) consisting of three gyros and three accelerometers will be developed. The ISA design would be compatible with future IMU packaging, but the electronics and light source will be external. The tethered IMU will be integrated and tested.
Once this development is concluded, a final form factor IMU, either as integrated unit with miniaturized electronics, or as tethered ISA with remote electronics, could be developed based on the final user requirements/form factor. Commercial IMU applications of the new gyro components by partnering with an IMU vendor will be pursued along with Army autonomous modular payloads and other military applications for possible use of this new technology.
Submission Information
For more information, and to submit your full proposal package, visit the DSIP Portal.
SBIR|STTR Help Desk: usarmy.sbirsttr@army.mil
References:
- Lefèvre, H. C. Fundamentals of the interferometric fiber-optic gyroscope. Opt. Rev. 4, 20–27 (1997).; G.A. Pavlath, “Fiber Optic Gyros:
- The Vision Realized,” 2006, Available at: http://www.nsd.es.northropgrumman.com/Html/Emerging-Technology-White-Papers/PDFs/Fiber-Optic_Gyros.pdf.;
- Jared F. Bauters, Martijn J. R. Heck, Demis D. John, Jonathon S. Barton, Christiaan M. Bruinink, Arne Leinse, René G. Heideman, Daniel J. Blumenthal, and John E. Bowers, “Planar waveguides with less than 0.1 dB/m propagation loss fabricated with wafer bonding,” Opt. Exp. 19, 24090 (2011).;
- Kuanping Shan, Shibnath Pathak, Binbin Guan, Guangyao Liu, and S.J.B. Yoo, “Low-loss compact multilayer silicon nitride platform for 3D photonic integrated circuits,” Opt Express 23(16), 21334-21342 (2015).;
- W.K. Bischel and L. Reichertz, “Mulitlayer Waveguide Optical Gyroscope,” US Patent 10852137 (2019).; Mike Horton, “Planar silicon nitride waveguide and silicon photonics integrated circuit for commercial optical gyroscope,” Proc. SPIE PC12105, Fiber Optic Sensors and Applications, XVIII, (13 June 2022); https://doi.org/10.1117/12.2617427.;
- Sudharsanan Srinivasan, Renan Moreira, Daniel Blumenthat and John E. Bowers, “Design of integrated hybrid silicon waveguide optical gyroscope,” Opt. Express 22 (21), 24988-24993 (2014).;
- Beibei Wu, Yu Yu, Jiabi Xiong and Xinliang Zhang, “Silicon Integrated Interferometric Optical Gyroscope,” Nature/Scientific Reports 8, 8766 (2018).