edward daykin* abel diaz, cenobio ... - ohio state university

WORK IN PROGRESSA Multiplexed Many-Point PDV (MPDV)

Techniques and Technologies

Edward Daykin*Abel Diaz, Cenobio Gallegos,

Carlos Perez, Araceli Rutkowski(* Daykinep@NV.DOE.GOV)

Presented to The 5th Annual PDV WorkshopThe Ohio State University

September 8, 2010

This work was done under Contract No. DE-AC52-06NA25946 with the U.S. Department of Energy.

DOE/NV/25946--1071

Motivation: Digitizer Cost & Availability of Digitizer Bandwidth and Memory

Digitizer MemoryTypical data lasts a few microseconds; digitizer memory allows record lengths ~ millisecond Time Multiplexing

Digitizer BandwidthTypical data uses a few gigahertz; digitizer bandwidth & sampling allow ~ 10 to 20 GHz Frequency MultiplexingAvailable Frequency Space

… please use me

2September 8, 2010

Inspiration: Bruce Marshall How to Complicate an Elegantly Simple Measurement without

Really Trying … PDV Workshop 2006

3September 8, 2010

• Wavelength division multiplexing– Lasers available on the ITU Grid?– Laser frequency ‘spacing’?– Application of Dense Wavelength Division Multiplexers (DWDMs)?

• Time division multiplexing– Coherence length and degree of polarization effects?

• Optical heterodyne approach: optical up-shift OR down-shift– Laser wavelength tunable?– Laser stable in frequency to ~ 10 MHz for hours?– Flexibility to up-shift for increased precision OR down-shift for

increased ‘effective’ bandwidth (e.g. high velocities)?

• A Laser Safe System– Optical pre-amplification on the ‘back end’ vs conventional high

power amplification on the ‘front end’?– Pre-amp gain saturation & dynamic hole burning affects?

Some Topics of Interest

4September 8, 2010

Evaluation of Photonic Technologies and Techniques

Seed Laser on ITU Grid

How can we leverage commercially available Telecom hardware?

5September 8, 2010

EDFA Optical Amplifier

DWDM

RedfernIntegratedOptics Inc.“RIO ORION”www.rio-inc.com

Wavelength Division Multiplexing – Notional

DW

DM

Mu

x

P

P

P

P

DW

DM

Mu

x

DW

DM

DeM

ux

Laser, ITU29Laser, ITU31Laser, ITU33Laser, ITU35

DW

DM

Probe 1-1Probe 1-2Probe 1-3Probe1-4

VariableOpticalAttenuators

F/O PowerMonitors

ToPhoto-Detector

6September 8, 2010

Seed Lasers: CW Power = 10 mWLinewidth = 15 kHz

ITU29 = 1554.13 nm (192900 GHz)ITU31 = 1552.52 nm ( 193100 GHz)ITU33 = 1550.92 nm (193300 GHz)ITU35 = 1549.32 nm (193500 GHz)

= 200 GHz

Wavelength Division Multiplexing with Optical Pre-Amplification – Notional

DW

DM

Mu

x

P

P

P

P

DW

DM

Mu

x

DW

DM

DeM

ux

Laser, ITU29Laser, ITU31Laser, ITU33Laser, ITU35

DW

DM

Probe 1-1Probe 1-2Probe 1-3Probe1-4

EDFA

ToPhoto-Detector

7September 8, 2010

Optical Pre-AmpErbium Doped Fiber Amplifier (EDFA)

Multiplexing, Pre-Amp & Optical Heterodyne

DW

DM

Mu

x

Laser, ITU29Laser, ITU31Laser, ITU33Laser, ITU35

DW

DM

Mu

x

P

P

P

P

DW

DM

Mu

x

DW

DM

DeM

ux

Laser, ITU29Laser, ITU31Laser, ITU33Laser, ITU35

DW

DM

Probe 1-1Probe 1-2Probe 1-3Probe1-4

EDFA 1x2

F/O CombinerToP-D

‘Local Oscillators’

8September 8, 2010

P

Temperature Tuned to User Determined Beat Frequency

Wavelength Division Multiplexing & Optical Heterodyne Up-Shifting … Lab Data

Laser Driven ‘Slapper Foil’ Triplexed Lab Data

9September 8, 2010

… and Time Division Multiplexing (~ 25 s)

10September 8, 2010

EDFA

Fiber-Optic Delay Line

DW

DM

DeM

ux

Laser Safe PDV: EDFA Pre-Amplification Benchmark Measurements

DW

DM

Mu

x

Laser, ITU29Laser, ITU31

DW

DM

Mu

x

P

P

DW

DM

DeM

ux

Laser, ITU29

Laser, ITU31

Probe 1

EDFA

1x2

F/O Combiners

ToP-D #1

‘Local Oscillators’

EDFA

Booster Amp125 mW

10 mW

Pre-AmpChannel

ITU29

ITU31

PRtn

ReferenceChannel

Compare Booster Amp ‘front end’ (prior to circulator) vs Pre-Amp ‘back end’ (post circulator)

11September 8, 2010

P

1x2ToP-D #2

September 8, 2010 Page 12

Benchmark Lab Data

‘Conventional’ PDV, No pre-amp : launch power = 125 mW, probe efficiency =14 dB, recorded onto digitizer channel 1

Laser Safe PDV, With EDFA pre-amp : launch power = 10 mW, probe efficiency range 14 dB to 60 dB, recorded onto digitizer channel 2

Laser Safe PDV: Benchmark Data

Pre-Amp Channel PRtn= -4 dBm

Reference ChannelPRtn= 7 dBm(Attenuated to match pre-amp power)

Pre-Amp Channel PRtn= -30 dBm

Pre-Amp Channels PRtn = -40 dBmPRtn = -50 dBm

13September 8, 2010

Optical power at photo-diode for Pre-Amp Channel & Reference Channel adjusted to be equal in all cases

• Multiplexing techniques promise increased PDV channel count, improved fidelity and improved cost effectiveness.

• Heterodyning is advantageous – allows user verification of beat signal amplitude (data quality assurance), flexibility to determine beat frequency (up/down shift), improves precision (see D. Dolan).

• Laser safe PDV operations via EDFA pre-amp appear feasible for probe efficiencies greater than ~ 40dB.

• Future Investigations:– Complete assembly of a 4x MPDV demonstration system for further testing on

high explosive experiments.– Investigate methods to ‘manage’ polarization dependence– Investigate methods to ‘gain clamp’ or ‘gain compress’ return signals to avoid

data loss upon saturation.

September 8, 2010 Page 14

Concluding Remarks & Future Investigations

September 8, 2010 Page 15

Acknowledgements

• Howard Bender, Program manager for NSTec SDRD Program

• Cenobio ‘Sonny’ Gallegos and his laser driven slapper laboratory

• Araceli Rutkowski et al. and her high frequency laboratory

• Carlos Perez and his perseverance with vendors and making it all work

• Many helpful discussions with Ted Strand (LLNL) and David Holtkamp (LANL)