5 ‐ 6 May 2012Aspekt 12 ‐ Bad Boll1
Fibre links and Image Slicers
CAOS• Gerardo Avila• Vadim Burwitz• Carlos Guirao• Jesús Rodriguez
CAOS
Contents of our presentation
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Fibre linksFibres for astronomical instrumentsAssembling fibre links
Image slicersReflectiveRefractive
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Fibre problems
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ThroughputInternal transmissionFresnel lossesFocal ratio degradation (FRD)Circular Vs. rectangular apertures
CouplingLensesEfficiency
AssemblingMaterialsPolishingAlignment
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0
10
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400 500 600 700 800 900
Internal tran
smission
(%)
Wavelength (nm)
20 m
FBP FVP
Fibre transmission (internal) in 20 m
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Gradient Index Fibres ‐ Internal transmission
T T L L' ' /=
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FRD in gradient index fibres
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0
10
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60
70
80
90
100
2 3 4 5 6 7
Efficiency [%
]
F / # Output
FRD62.5um gradient index fibre, 2m, free
F/3.3
F/4.2
F/5
F/6.7
20.01.2009
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Total transmission of Tapers
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0
10
20
30
40
50
60
70
80
90
100
2 3 4 5 6 7 8 9 10
Total efficiency [%
]
F/# ‐ output
FRDTaper fibre (300um to 100um), 10m, free, spot size 250um,
light source: green HP‐LED (525nm)
F/ 10 (58 % @ F/ 3.3)
F/ 15 (34 % @ F/ 5)
16.06.2009
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Non‐circular fibres
5 ‐ 6 May 2012Aspekt 12 ‐ Bad Boll10Focal Ratio Degradation study of non‐circular shaped fibresT. Feger, M. Goodwin, C. L. Poppett
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Minimizing FRD with focal reducers
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Image of telescope pupilon input fibre end
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Minimizing FRD with focal reducers
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Image of star oninput fibre end.
Bad example: not optimal telescope‐fibre pupil matching
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Minimizing FRD with focal reducers
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Image of star oninput fibre end
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Preparation of a fibre link
Fibre ConnectorFibre Axis
Connector Ax
Ferrule