Fabrication of highly precise fiber optical array products by use of - - PowerPoint PPT Presentation

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: info@blz.org

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

Motivation

What 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

Motivation

Thermal 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

Motivation

Industrial Applications

Reference: Philips

Optical drives

Reference: Philips

4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria

Design of an Actuator System

Design 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 System

Simulation and Optimization of Fiber Collimator Arrays

4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria

Design of an Actuator System

Simulation and Optimization of Fiber Collimator Arrays 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 µm Temperature gradient

Design of an Actuator System

Simulation and Optimization of Fiber Collimator Arrays

• Thickness ↓ - Dumping ↓

4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria

Temperature

Design of an Actuator System

Simulation and Optimization of Fiber Collimator Arrays 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 System

Experimental 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 System

Experimental Results – Laser Micro Alignment

2 4 6 8 10 12 2 4 6 8 10 Number of Pulses

Displacement [µm] 19 mJ 36 mJ 82 mJ

Pulse Energy

4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria

Conclusion

Laser 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?