Ultra-Stable Lasers
Supervisor
Dr Randy Bartels
Team Members
Steven Dorlac, Andrew Wiersma, Daxsamuel Chitechi, Derrick Bernallie
Ultra-Stable Lasers
Project Overview
• Develop an Optically-Based Clock
– Ultra-Stable External Cavity Diode Laser (ECDL)
• Stable Optical Frequency Comb
(image shown on right)
• Driving/Stabilizing Electronics
– Applications
• Precision Clocks
• Telecommunications
• Precision Navigation
Source: Encyclopedia of Laser Physics and
Technology (website)
Ultra-Stable Lasers
ECDL System Overview
• Key Components
–
–
–
–
External Cavity Diode Laser
Thermoelectric Control (TEC)
Power Supply (PSU)
Piezo-Electric Power Supply
(PZT PS)
– Diode Driver
– Loop Control/Filter
– Optics
Current
Controller
Ultra-Stable Lasers
Semester Goals and Assignments
• Develop ECDL electronics
– Diode Driver: Andy Wiersma
– TEC: Dax Chitechi
– Power Supply: Derrick Benallie
– Control/Filter: Steven Dorlac
Current Controller
• Supplies a very low noise
current to the LASER diode
• Typical Inputs
– Power Supply
• Supplies power to the Current
Driver to produce a current
– Servo Circuit
• Provides feedback to the
Current Driver to compensate
for changes
• Typical Outputs
– Laser Diode
• Supplies Current to the Diode
Current
Controller
Current Controller Overview
Current Controller Key Parts
1) Supply
Source
2) Circuit
Feedback
3) Current Line
4) Output to
Diode
Thermoelectric Controller
• Maintain the ECDL at
constant temperature.
• Typical inputs:
– Thermistor &
thermocouple
• Typical outputs:
– Peltier cooler & heater
TEC
Thermoelectric controller overview
Thermoelectic Controller Key Parts
1) Low power
low cost
2.5V
reference
2) Gain stage
3) Peltier
cooling and
heating
stage
Power Supply
• Supplies Power other Circuits
– General power
• TEC
• PZT PS
• Current Controller
• Cost effective to simply
purchase
PSU
Pulsed Power Supply
• Supplies Power to the PZT
Driver
– Provides high voltage supply
to supply to PZT
• Piezoelectric Disc
– Mounted to back of optical
mirrors
– Changes Cavity Length
• Changes output freqency
PZT PS
Pulsed Power Supply
Pulsed Power Supply
• More efficient
• Carefully designed not
to have high power
peaks
Control/Filter Electronics
• Stabilizes ECDL Frequency
• Can be cascaded
• Typical Inputs
– Photodetector
• Typical Outputs
– Piezo Disc
• Adjusts External Cavity
– Diode Driver
• Adjusts Current to Diode
Control
Control/Filter Electronics
Key Components
Budget
1) Current Controller Parts: $138.43
2) Thermoelectric Cooling Parts: $76.15
3) Power Supply Parts: $133.77
4) Loop Electronics Parts: $109.31
-Total for parts so far:$457.67
-Amount coming in from senior design: $350
-We plan on getting the rest of our funding from Prof.
Bartels for the PCB and any extra costs we come across
-PCB: ~$50 for each circuit= $200
-One major expense we still have other than the PCB is two
EMCO model G03 which we are currently looking for more
affordable alternative replacement parts
Review
• ECDL Circuits
– Connections
– Purpose
– Features
Current
Controller
Next Semester Plans/Goals
• Design, Integrate and Build ECDL components
– Diode Housing, External Cavity, Mirrors, Gratings, Piezo Discs,
Photodetector
• Assemble ECDL system
– Attach electronics
– Setup and calibration of electronics
• Achieve stable optical comb output from ECDL
Thanks for Listening
Any Questions?