Curvature Wavefront Sensor Curvature Wavefront Sensor Arbitrary Waveform GeneratorArbitrary Waveform Generator

Kenyan KawauchiKenyan Kawauchi

Subaru Telescope (NAOJ)Subaru Telescope (NAOJ)

Mentor: Stephen ColleyMentor: Stephen Colley

Subaru Adaptive OpticsSubaru Adaptive Optics

Earth’s atmospheredistorts light

Telescopeimages blurred

Removes effectsof atmospheric

distortion

Image resolutionimproved

Without AO With AO

AO System ComponentsAO System Components

Wavefront SensorWavefront Sensor

Visible light reflectsoff one sideof membrane

Measure lightintensity

APDs count photonsin each lenslet

Calculate wavefrontphase shift

What vibrates membrane?What vibrates membrane?

Other side of membrane

ProblemProblem

SolutionSolution

• Design your own AWG!

• Use DAC40 board

• Field Programmable Gate Array (FPGA)

• Digital-to-Analog Converters (DACs)

AWG SpecificationAWG Specification Range of period – 100 Hz to 4 kHzRange of period – 100 Hz to 4 kHz Number of points – 1000Number of points – 1000 Voltage resolution – 14 bits (DAC40 DACs) Voltage resolution – 14 bits (DAC40 DACs) Update rate for new waveforms – 0.1 seconds Update rate for new waveforms – 0.1 seconds

(10 Hz)(10 Hz)

Voltage Amplitude

Time

Logic Block DiagramLogic Block Diagram

AWG

Timing Memory

A B

Implement using Quartus IIImplement using Quartus II

Design FlowDesign FlowDesign Entry

(VHDL)Compilation Simulation

ProgramDevice

Simulate DesignSimulate DesignDesign Entry

(VHDL)Compilation Simulation

ProgramDevice

ConclusionConclusion

Dual-stroke waveform conceptDual-stroke waveform conceptEfficient – Only 1 wavefront sensorEfficient – Only 1 wavefront sensorAstronomical objects appear 2.5X brighterAstronomical objects appear 2.5X brighter

In the FutureIn the Future- Interface DAC40 to oscilloscopeInterface DAC40 to oscilloscope- Test AWGTest AWG- Implement in next generation AO systemImplement in next generation AO system

AcknowledgementsAcknowledgements

Stephen ColleyStephen ColleyOlivier Guyon – Subaru AstronomerOlivier Guyon – Subaru AstronomerHideki Takami – AO Project ManagerHideki Takami – AO Project ManagerSubaru Telescope (NAOJ)Subaru Telescope (NAOJ)Center for Adaptive OpticsCenter for Adaptive Optics Funding provided through the Center for Adaptive Funding provided through the Center for Adaptive

Optics, a National Science Foundation Science and Optics, a National Science Foundation Science and Technology Center (STC), AST-987683Technology Center (STC), AST-987683