Atomic-Photonic Integration (A-PhI) A-Φ Proposers Day Dr. John Burke Microsystems Technology Office (MTO) 1 August 2018 1
What is A-PhI? Atomic physics allows for accurate and sensitive measurements. Supporting systems are very large, and it s often because of optics and vacuum systems. source: www. euramet.org 560 µm The atomic package necessary to utilize atomic physics is small. A-PhI is a program that will allow the small size and accuracy of atomic physics to shine through photonic integrated circuits (PICs): Atomic-Photonic Integration. 2
A marriage of atomic systems and photonics A Knowledge of sources Experience with measurement Have testing facilities Familiar with potential pitfalls Φ Knowledge of materials Familiar with process Can replace optical train Experienced designers source: www.nist.gov A-Φ The high accuracy of atomic systems with the portability, manufacturability, and robustness of photonic integrated chips. Source: IEEE Journal of Selected Topics in Quantum Electronics, 2016, 22, 8300209 A marriage for the ages source: flickr.com/photos/whinendine 3
A-PhI technical problem summary Clock TA1 Convert known trapping & cooling geometries to PIC Generic diagram for atom-based quantum systems Gyro TA2 Architect atom physics trap with area enclosing geometry Demonstrate atom analog of IFOG source: Science 2013, 341, 1215 Convert optical filters to PIC Convert developed cooling & trapping geometry on PIC 1 cm source: www.slsoptics.com 20 cm source: UCSB Future Work A-PhI will develop the two critical layers of the new paradigm stack 4
Photonics requirements for clocks: Low-loss waveguides and optical frequency combs Optical Clock Transitions Yb+ Sr+ Yb Sr 350 550 750 950 1150 SiN (n=2.02-2.07) 450 nm cutoff Al 2 O 3 (n= 1.76-1.83) 270 nm cutoff SiO 2 (n = 1.45-1.49) 280 nm cutoff Atom cooling 1 Atom cooling 2 Repump 1 Repump 2 Magic wavelength trap Clock transition Sr wavelength 460.9 689.3 707.2 679.3 813.4 698.4 Sr linewidth 32 MHz 7.5 khz ~MHz ~MHz ~1 mhz Sr Power ~100 mw ~10 mw ~5 mw ~5 mw ~W ~10 mw Similar data can be obtained for Yb, Sr+, Yb+ Optical power for the ions is lower but requires bluer lasers Both neutral and ions will require optical frequency combs Rev Mod Phys, vol. 87, no. 2, pp. 637-701, 2015 Boyd Thesis (2007) Bloom Thesis (2010) Campbell Thesis (2017) 5
Trapped atom gyroscopes Fiber optic gyro (IFOG) Performance (# turns) (area) Area = 17,000 mm 2 ~10,000 turns Ω Area 15 cm A-PhI split source: Wikipedia Trapped atom gyro interference Based on light wave interference Light trapped in optical fiber Cold atom gyro Cold atom Looped path ~1 cm Area = 40 mm 2 1 turn source: http://web.stanford.edu/group/kasevich/cgi-bin/wordpress/?page_id=11 Uses wave property of matter Atoms have 10 10 physics enhancement 6
State-of-the-art timing 10 9 1.E+09 Trapped Atom Time to 1 ns error (sec) 10 6 1.E+06 10 3 1.E+03 10 0 1.E+00 Year Month Day Hour Silicon MEMS TCXO ACES CSAC OCXO A-PhI Rb Osc SOA OCXO Cs beam Cold Atom Maser Quartz/MEMS Atomic Quartz/MEMS 10-3 1.E-03 1.E-06 1.E-04 1.E-02 1.E+00 1.E+02 1.E+04 10-6 10-4 10-2 10 Size [Liters] 0 10 2 10 4 Size (Liters) Atoms accuracy, atoms are identical Cooled remove thermal noise Trapped remove acceleration effects Optical 10 5 higher sensitivity vs. RF 7
State-of-the-art gyroscopes 1.000E-07 Angle Random Walk (deg/hr 1/2 ) 10-7 1.000E-06 10-6 1.000E-05 10-5 1.000E-04 10-4 1.000E-03 10-3 1.000E-02 10-2 1.000E-01 10-1 ADXRS646 HG1930 KVH1750 A-PhI Northrop HRG RH-IFOG HG9900 HG1700 Free-space atom 1.000E+00 10 0 1.00E-041.00E-031.00E-021.00E-01.00E+001.00E+011.00E+021.00E+031.00E+04 10-4 10-3 10-2 10-1 10 0 10 1 10 2 10 3 10 4 Size (L) 8
A-PhI technical areas FY2019 FY2020 FY2021 FY2022 FY2019 FY2020 FY2021 FY2022 FY2023 Phase 1 18 months Phase 2 18 months Phase 3 12 months Photonic interface for trapped atom clock Breadboard clock TA1 Clock Demo atom interface Demo low noise laser oscillator Demo clock Demo oscillator Future Work: Lasers and Electronics miniaturization Environmental test Transition to other applications Trap for atom gyro Trapped atom gyro scaling & dynamics TA2 Gyro Demo 10 mm 2 Sagnac interferometer New BAA Contracting Photonic interface for trapped atom gyro Demo Atom-PIC gyro Demo dynamic operation and refine Sagnac interferometer Photonic interface to trap and interrogate atoms for gyroscope not part of Phase 1 or 2 9
A-PhI TA-1 metrics and milestones Notes are addressed in the full BAA. 10
A-PhI TA-2 metrics and milestones Notes are addressed in the full BAA. Phase 3 metrics are intended as a guide for performance metrics in Phases 1 and 2. 11
Key notes Free-space optics are defined as: Discrete optical elements, which convert an unguided, free-propagating spatial mode of light to another freepropagating spatial mode. examples include, but are not limited to: lenses, mirrors, prisms, and polarizers. source: Ealing source: Comar Thin, planar-fabricated optics (e.g. meta-material lenses, micro-lens arrays, and gratings) may be excluded from the free-space optic count if they are easily integrable and significantly lower both the cost and complexity of the design. source: ThorLabs source: Edmund At the conclusion of Phase 1 performers will complete an analysis demonstrating that the technology is capable of achieving the Phase 2 program objectives. The analysis will detail the proposed laser intensity and frequency for each laser beam, as a function of time through the clock measurement cycle, and this should match the demonstrations on the components. 12
What we envision Power conditioning, control electronics, and laser systems are not included in the physics package. If the laser requires frequency narrowing external to the laser cavity, then the components required for the narrowing should be considered part of the A-PhI physics package. Proposals should identify the lasers that will be used. 13
Technical Approach Guidance TA1 Although the development of a compact atomic clock is not a part of this solicitation, the goal of the program is to enable a system where all of the components are miniaturized. Therefore, the amenability of the proposed laser component to future miniaturization will be considered when evaluating the proposed solutions. TA2 The optical bench of the atom gyroscopes must be amenable to being replaced with a PIC device in subsequent research. 14
Contribution to DARPA mission Proposers should highlight the contribution of their proposed research to the DARPA mission. Proposers should also describe previous efforts and their impact on DARPA s mission and on U.S. National Security, as relevant. A history of transitioning government-funded technologies to supporting national interests will impact scores positively, while transitioning government-funded technology or related technologies to foreign entities or through foreign influence will negatively impact evaluation scores. 15
Submission timeline Posting Date: 25 July 2018 Proposers Day: 1 August 2018 Abstract Due Date: 16 August 2018 FAQ Submission Deadline: 20 September 2018 Proposal Due Date: 27 September 2018 Estimated Period of Performance Start: March 2019 16
Proposers day agenda 9:00 9:30 am Check-in 9:30 9:35 am Welcome Security Brief 9:35 10:05 am Contract Management Brief 10:05 10:15 am MTO Overview 10:15 10:45 am A-PhI Overview 10:45 11:00 am Questions Submission / Break 11:00 am 12:10 pm Teaming/Capabilities Presentations 12:10 12:50 pm Lunch 12:50 1:20 pm Answers to Questions 1:20 1:40 pm Poster Session Set-up 1:40 5:00 pm Poster Session 1:40 6:15 pm Sidebars with Program Manager 17
www.darpa.mil 18