UV-RGB The integrated UV-RGB laser beam-combiner

Sponsored by the IOP Photonic Devices
UV-RGB
The integrated UV-RGB laser beam-combiner
Ger Folkersma
“UV-RGB”: The integrated UV-RGB laser beam-combiner
Prof. dr. ir. A.J. Huis in 't Veld
Dr. ir. D.M. Brouwer
Dr. ir. G.R.B.E. Römer

� Health and medicine
– Confocal microscopy
– Fluorescence microscopy
– Flow cytometry
� Lithography
� Optical inspection
� Consumer entertainment
� Etc.
Laser beam combiner: Applications
Multiple wavelengths of laser light in one beam
BEST food sorting
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XiO ILBC: Integrated Laser-Beam Combiner
• Robust
• Small
• No (re)alignment
• Convenient
Laser beam combiners
Schäfter & Kirchhoff (D)
MLC 400 monolithic laser combiner, Agilent (US)
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� ILBC: Integrated Laser-Beam Combiner
Introduction
– Combine multiple wavelengths of laser light into one optical fiber
– Beam combiner on a single optical chip from XiO Photonics
Specs
– Single mode, polarization maintaining
– 100mW input power
– Wavelength 375 – 785 nm
– Low-loss (50% overall)
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Fiber – fiber pluggable connectors
Fiber – chip interconnect
Research areas
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� Current problems
– Alignment requirements
– Tolerances
– Fixation/ bonding
� Conceptual solution
– Post-bond alignment
– Laser adjusting
� Future work
Contents
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� Experiment to validate model
Coupling efficiency (%)
100
90
80
70
60
50
40
30
20
10
– Two fibers, lateral offset
– Spectral power measurement
– First results show good agreement
Power loss lateral offset
Alignment requirements
488nm measured
561nm measured
640m measured
488nm theory
561nm theory
640nm theory
Broadband
lightsource
0
0 0.5 1 1.5 2 2.5
offset (�m)
Spectral
analyzer
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Current fiber-chip connection
Fiber Array Unit (FAU) � Bond multiple ports at once
� Optical fibers
� Tolerances ±0.5μm
– Polarization maintaining, single mode
– Core-Clad concentricity < 0.5 µm
� Limited by micromachining process
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� Alignment by power loss minimization
� Adhesives bond FAU to chip
Current fiber-chip connection
– Shrinkage during curing problematic for alignment
– Adhesives exposed to UV degrade
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� Connectors from telecommunication
– Widely used -> cheap
– Too wide tolerances
� Not suitable for UV wavelengths
� High performance connectors
– Expensive
– Assembled and aligned at manufacturer
Fiber connectors
ST FC SC
E2000
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� Fiber – chip coupling
– Required alignment accuracy

� Re-align after bonding
– Less demanding alignment during bonding
– Correction of shrinkage
� Manipulator to move the fiber
– Integrated in the product
Post bonding alignment
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� Deformation due to laser heating
– Contactless
– Good ‘resolution’
– Suitable for miniaturization
� Model required to predict “actuator”
behavior
� Design 5-DOF manipulator for aligning the
fiber
Laser adjusting
M. Dirscherl (D), 2006
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Laser adjusting, first model
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� Design integrated manipulator
– Modeling and experimenting with laser adjusting
– Predictive model for laser adjustment
� Investigate bonding methods
– (laser) welding
– Soldering
� Perform bonding + alignment experiments
– Bonding and aligning a fiber to a chip
� Expand to generic method
Future work
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