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

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

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 Free Space Light Coupling • Efficient coupling of light into fibers or between fibers where multiple parallel optical fibers are used • Especially single-mode communication 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

Motivation Thermal Laser Adjustment Temperature-Gradient-Mechanism (TGM) 1. Heating by laser 3. Cooling 2. Gradient formation, radiation plastification Upsetting Mechanism 4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria

Motivation Industrial Applications Optical drives Reed-contacts laser beam laser beam Reference: Philips 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 • d Fiber : 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

Design of an Actuator System Simulation and Optimization of Fiber Collimator Arrays Process data - Max./min. displacement Laser - Max. temperature Actuator - Power [W] - Min. dumping - Thickness - Pulse width [ τ p ] - Length - Frequency [f p ] FEM-Model - Width of bridge SYSWELD - Location of SYSTUS International radiation Results - Displacement - Temperature - Dumping 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

Design of an Actuator System Simulation and Optimization of Fiber Collimator Arrays Defined Limits for Actuator Alignment • upper limit of dumping 0.175 rad/mm Dumping Actuator thickness: 50 µm uniform heating • Thickness ↓ - Dumping ↓ Actuator thickness: 400 µm Temperature gradient 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 Defined Limits for Actuator Alignment • Maximum temperature at center of actuator 350° C Temperature • 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

Design of an Actuator System Experimental Results – Laser Micro Alignment • Displacement of actuator with different number of pulses 12 Pulse Energy 19 mJ 10 36 mJ 82 mJ Displacement [µm] 8 6 4 2 • 10 µm displacement 0 0 2 4 6 8 10 • Requirements fulfilled Number of Pulses 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? 4M2007 Conference on Multi-Material Micro Manufacture 3-5 October 2007 Borovets Bulgaria