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4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria
Fabrication of highly precise fiber optical array products by use of laser based micro alignment
M. Zimmermann, L. Schaefer, M. Rank, M. Schmidt, S. Roth
Bayerisches Laserzentrum GmbH, Konrad-Zuse-Str. 2-6, 91052 Erlangen,
Germany, Email: [email protected]
4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria
Outline
Introduction and Motivation
Design of an Actuator System
- Simulation and Optimization
- Experimental Results
Conclusion
4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria
Free Space Light Coupling
• Efficient coupling of light into fibers or between fibers where multiple parallel optical fibers are used
• Especially single-mode communication
MotivationWhat is a Fiber Collimator Array?
Design
• Combination of a fiber array and a micro lens array
• Collimation of the light transmitted from a fiber
• Coupling light into a fiber by focusing
Pointing Accuracy σ
• Angle of the collimated beam with
respect to the optical axes• Depends on: lateral fiber offset ∆∆∆∆x
4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria
1. Heating by laser radiation
2. Gradient formation,plastification
3. Cooling
MotivationThermal Laser Adjustment
Upsetting Mechanism
Temperature-Gradient-Mechanism (TGM)
4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria
laser beam
laser beam
Reed-contacts
MotivationIndustrial Applications
Reference: Philips
Optical drives
Reference: Philips
4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria
Design of an Actuator SystemDesign of Fiber Collimator Arrays
Properties
• Pitch: 2 mm
• Fiber: Singlemode
• dFiber: 125 µm
• MLA: fused silica
Requirements
• Total displacement 10 µm
• Displacement steps minimum 0.1 µm
• No thermal damage of the adhesive
• Mechanical stability
4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria
Laser
- Power [W]
- Pulse width [τp]
- Frequency [fp]
- Location of radiation
Actuator
- Thickness
- Length
- Width of bridge FEM-Model
Results
- Displacement
- Temperature
- Dumping
SYSWELD SYSTUS International
Process data
- Max./min. displacement
- Max. temperature
- Min. dumping
Design of an Actuator SystemSimulation and Optimization of Fiber Collimator Arr ays
4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria
Design of an Actuator SystemSimulation and Optimization of Fiber Collimator Arr ays
Displacement y-direction
• Thickness ↓ - Displacement ↑
• Fiber displacement in
arbitrarily direction possible!
4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria
Dumping
Defined Limits for Actuator Alignment
• upper limit of dumping 0.175 rad/mm
Actuator thickness: 50 µm uniform heating
Actuator thickness: 400 µmTemperature gradient
Design of an Actuator SystemSimulation and Optimization of Fiber Collimator Arr ays
• Thickness ↓ - Dumping ↓
4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria
Temperature
Design of an Actuator SystemSimulation and Optimization of Fiber Collimator Arr ays
Defined Limits for Actuator Alignment
• Maximum temperature at center of actuator 350°C
• Thickness ↓ - Temperature ↑
• Thickness 100 µm - 200 µm
4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria
Design of an Actuator SystemExperimental Results – Laser Micro Alignment
Measurement of
pointing accuracy
Laser 1310 nm
4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria
• Displacement of actuator with different number of pulses
• 10 µm displacement
• Requirements fulfilled
Design of an Actuator SystemExperimental Results – Laser Micro Alignment
0
2
4
6
8
10
12
0 2 4 6 8 10Number of Pulses
Dis
plac
emen
t [µm
]
19 mJ36 mJ82 mJ
Pulse Energy
4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria
ConclusionLaser Micro Alignment
- Alignment in µm range is possible
- Simulation: sub-µm adjustment
- Temperature treatment of adhesive and assemblies
- Laser irradiation strategy reduces heat stress
- Time-consuming actuator design
- Outlook
- Sub-µm alignment -> precise sensor necessary
- Long term stability?
- Non-thermal adjustment
4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria
Thank you for your kind attention!
Questions?
