SYNTHESIS OF SINGLE-WALLED CARBON NANOTUBES (SWCNTs) FROM OPTICALLY PUMPED CARBON MONOXIDE
First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of...
Transcript of First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of...
![Page 1: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/1.jpg)
First results of a high performance optically-pumped cesium beam clock
Berthoud Patrick, Chief Scientist Time & Frequency
Workshop on Synchronization and Timing Systems, WSTS 2016, San Jose CA, USA, June 2016
![Page 2: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/2.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 2
Outline
• Motivation and applications
• Clock sub-systems development
• Clock integration results
• Conclusion and acknowledgment
![Page 3: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/3.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 3
Identified markets
• Telecommunication network reference • Telecom operators, railways, utilities, …
• Science • Astronomy, nuclear and quantum physics, …
• Metrology • Time scale, fund. units measurement
• Professional mobile radio • Emergency, fire, police
• Defense • Secured telecom, inertial navigation
• Space (on-board and ground segments) • Satellite mission tracking, GNSS systems
![Page 4: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/4.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 4
Available Cs clock commercial products
• Long life magnetic Cs clock • Stability : 2.7E-11 t-1/2, floor = 5E-14
• Lifetime : 10 years
• Availability : commercial product
• High performance magnetic Cs clock • Stability : 8.5E-12 t-1/2 , floor = 5E-15
• Lifetime : 5 years
• Availability : commercial product
• High performance and long life optical Cs clock • Stability : 3.0E-12 t-1/2 , floor = 5E-15
• Lifetime : 10 years
• Availability : under development
![Page 5: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/5.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 5
Motivation for an Optical Cs clock
• Improved performance (short and long-term stability) for: • Metrology and time scales
• Science (long-term stability of fundamental constants)
• Inertial navigation (sub-marine, GNSS)
• Telecom (ePRTC = enhanced Primary Reference Time Clock)
• No compromise between lifetime and performance • Low temperature operation of the Cs oven
• Standard vacuum pumping capacity
• Large increase of the Cs beam flux by laser optical pumping
![Page 6: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/6.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 6
Outline
• Motivation and applications
• Clock sub-systems development
• Clock integration results
• Conclusion and acknowledgment
![Page 7: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/7.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 7
Optical Cesium clock operation
• Cs beam generated in the Cs oven (vacuum operation)
• Cs atoms state selection by laser
• Cs clock frequency probing (9.192 GHz) in the Ramsey cavity
• Atoms detection and amplification by photodetector (air)
• Laser and RF sources servo loops using atomic signals
Ramsey
cavityLight
Collectors
Magnetic
shield + coil
FM
User
10 MHz
Laser
Cs Oven
Vacuum
enclosure
Photo-
detectors
RF
source
Sync
Detect
FM
Laser
source
Sync
Detect
Cs
beam
![Page 8: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/8.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 8
Optical pumping: principle of operation
• Stable ground states (F=3 and F=4)
• Switching between ground states F by RF interaction 9.192 GHz
• Unstable excited states (F’=2,3,4,5)
• Switching between ground states F and excited states F’ by laser interaction 852 nm (optical domain)
6S1/2 nhf = 9.192 GHz
F=4
F=3
6P3/2F’=4
F’=3
F’=2
F’=5
133Cs atomic energy levels
![Page 9: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/9.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 9
Cesium clock: Magnetic vs. Optical
• Weak flux • Strong velocity selection (bent) • Magnetic deflection (atoms kicked
off)
• Typical performances: • 2.7E-11 t-1/2
• 10 years
• Stringent alignment (bent beam)
• Critical component under vacuum (electron multiplier)
F=3,4
• High flux (x100) • No velocity selection (straight)
• Optical pumping (atoms reused)
• Typical performances: • 2.7E-12 t-1/2
• 10 years
• Relaxed alignment (straight beam)
• Critical component outside vacuum (laser)
N
S
N
S
F=3,4
![Page 10: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/10.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 10
Clock functional bloc diagram • Cs tube
• Generate Cs atomic beam in ultra high vacuum enclosure
• Optics • Generate 2 optical beams from 1
single frequency laser
• Electronics • Cs core electronics for driving the
Optics and the Cs tube
• External modules for power supplies, management, signals I/O
Cesium tube
Magnetic field and shields
Cs Oven
Collect CollectRamsey cavity
Optics
Laser Splitter Mirror
Clock electronicsRF
Source
Clock Ctrl Power Supply
Photo Detect
Photo Detect
4x S
ync
ou
t (1P
PS)
Expansion electronics
Seri
al (
RS2
32)
Sync
in (
1PPS
)
Dis
pla
y
10 M
Hz
sin
e10
MH
z si
ne
10 o
r 5
MH
z si
ne
(opt
ion)
10 o
r 10
0 M
Hz
sin
e (o
ptio
n)
MetrologyManage
ment
Rem
ote
(TC
P/IP
)
PPS DC/DC AC/DC Battery
Exte
rnal
DC
sup
ply
Exte
rnal
AC
su
ppl
y
![Page 11: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/11.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 11
Clock architecture (top view)
• Cs core is not customizable
• External modules are customizable: • Power supplies
• Signal outputs
• Management
![Page 12: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/12.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 12
Cs tube sub-assembly
![Page 13: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/13.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 13
Optics sub-assembly • Optical sub-system
• Free space propagation
• Single optical frequency (no acousto-optic modulator)
• Redundant laser modules (2)
• No optical isolator
• Ambient light protection by cover and sealing (not shown here)
• Laser module • DFB 852 nm, TO3 package
• Narrow linewidth (<1MHz)
![Page 14: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/14.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 14
Physics Package
Optics
Cs tube
Laser modules
Photo-detectors modules
![Page 15: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/15.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 15
Complete Cs clock
• Front view • LCD touchscreen
• Top view • Optics + Cs tube in front
• Core electronics
• Rear view • Power supplies (AC, DC,
Battery)
• Sinus Outputs (5, 10, 100 MHz)
• Sync 1PPS (1x In, 4x Out)
• Management (RS 232, Ethernet, Alarms)
![Page 16: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/16.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 16
Outline
• Motivation and applications
• Clock sub-systems development
• Clock integration results
• Conclusion and acknowledgment
![Page 17: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/17.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 17
Laser frequency synchronous detector
• Green curve: laser current (ramp + AM modulation)
• Blue curve: modulated atomic fluorescence zone A (before Ramsey cavity)
• Pink curve: demodulated atomic fluorescence in zone A
• Phase optimization for synchronous detector (max signal, positive slope on peak)
![Page 18: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/18.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 18
Laser frequency lock
• Automatic laser lock • Atomic line identification by
correlation in micro-controller • Laser optical frequency
centering (center of laser current ramp)
• At mid height of next ramp, automatic closing of frequency lock loop
• Optimization of laser lock loop • Tuning parameters:
amplitude of modulation, PID parameters
• Criterion: min PSD of laser current
• Reliability of laser lock
![Page 19: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/19.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 19
Ramsey fringes (Preliminary)
• Dark fringe behavior (minimum at resonance)
• Central fringe • Amplitude = 200 pA
• Linewidth = 800 Hz (FWHM)
• Background = 600 pA
• Noise PSD [1E-28*A2/Hz] • Photo-detector = 1.6
• Background light = 1.9
• Atomic shot noise = 0.5
• Extra noise = 6.2
• Total = 10.2
• SNR = 6’090 Hz1/2
![Page 20: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/20.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 20
Frequency stability (Preliminary)
• Measured frequency stability • ADEV = 7.5E-12 t-1/2
• Compared to H-maser
• Calculated frequency stability • ADEV = 7.1E-12 t-1/2
• Using SYRTE model (S. Guérandel at al, Proc. of the Joint Meeting EFTF & IEEE - IFCS, 2007, 1050-1055)
![Page 21: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/21.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 21
Outline
• Motivation and applications
• Clock sub-systems development
• Clock integration results
• Conclusion and acknowledgment
![Page 22: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/22.jpg)
© 2016 ADVA Optical Networking. All rights reserved. 22
Conclusion and acknowledgment
• Development of an industrial Optical Cesium Clock for ground applications
• All sub-systems are functional (Cs tube, Optics, Electronics)
• Preliminary frequency stability measurement ADEV = 7.5E-12 recorded for long life operation (10 years target)
• Present performance limitations: laser lock quality (extra noise)
• Acknowledgment: this work is being supported by the European Space Agency
![Page 23: First results of a high performance optically-pumped cesium … · 2018-11-08 · •Development of an industrial Optical Cesium Clock for ground applications •All sub-systems are](https://reader030.fdocuments.in/reader030/viewer/2022040410/5ec8e8671c491574b15ed47e/html5/thumbnails/23.jpg)
Thank You
IMPORTANT NOTICE ADVA Optical Networking is the exclusive owner or licensee of the content, material, and information in this presentation. Any reproduction, publication or reprint, in whole or in part, is strictly prohibited.
The information in this presentation may not be accurate, complete or up to date, and is provided without warranties or representations of any kind, either express or implied. ADVA Optical Networking shall not be responsible for and disclaims any liability for any loss or damages, including without limitation, direct, indirect, incidental, consequential and special damages, alleged to have been caused by or in connection with using and/or relying on the information contained in this presentation.
Copyright © for the entire content of this presentation: ADVA Optical Networking.