Direct fibre excitation with a digital laser 1 Proof of principle - - PowerPoint PPT Presentation

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direct fibre excitation with a digital laser
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Direct fibre excitation with a digital laser 1 Proof of principle - - PowerPoint PPT Presentation

Nov 01, 2023 130 likes •324 views

Direct fibre excitation with a digital laser 1 Proof of principle Mode transfer Mode detection Mode source 2 Digital laser resonator as the mode source 3 Digital laser in operation Nd:YAG Monitor 2 SLM Driver CCD PC 2 PC 1 SLM Video

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1

Direct fibre excitation with a digital laser

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2

Proof of principle

Mode source Mode transfer Mode detection

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Digital laser resonator as the mode source

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Digital laser in operation

CCD Monitor 2 PC 2 SLM Monitor 1 PC 1 Video signal SLM Driver Nd:YAG

time

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5

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Mode transfer - Standard step index fibre

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Modal detection - Modal decomposition technique

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We can determine the purity of the petals by azimuthal modal decomposition when using loss lines

  • 6 -5 -4 -3 -2 -1

1 2 3 4 5 6 0.0 0.1 0.2 0.3 0.4 0.5 |a

2|

Azimuthal, l

8petals-lines

l±4 97%

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Generation of Linear Polarised (LP) fibre modes

  • Digital Holograms: Generate Laguerre Gaussian (LG)

Modes from the digital laser

  • LG modes approximation to Linearly Polarised (LP) modes
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Injection and transmitted mode through the multimode fibre

  • Injected modes into a multimode fibre
  • Emitted modes through a multimode fibre
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Modal power spectrum – LP01

Fibre input (Digital laser) Fibre output

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Modal power spectrum – LP11

Fibre input (Digital laser) Fibre output

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Modal power spectrum - LP21e

Fibre input (Digital laser) Fibre output

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Modal power spectrum – LP21o

Fibre input (Digital laser) Fibre output

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Control mode coupling of LP11e and LP11o

  • Pre-calibration of the injected mode to achieve a desired outcome.
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Conclusion

  • Achieved to generate LP modes from a single source

and transmit these modes through an optical fibre with very high efficiency.

  • Achieved to control cross talk between modes by

controlling the mode from the source.

  • Next step will be to eliminate all telescope and optics

that cause aberration effects.

  • Future work : Test and apply the technology to existing

fibre network cable.

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Thank you

Dr Sandile Ngcobo (SNgcobo@csir.co.za)