CO2 Laser Fusion Splicing Between PBGF and SMF Dana Cristea Bridgewater College / KSU Physics Research 2006 Other members of LUMOS lab: Kristan Corwin, Rajesh Thapa, Kevin Knabe, Andrew Jones

Purpose What? ~ Sealing hollow optical fiber containing acetylene gas. Why? ~ Frequency metrology, atomic clocks and quantum/atom optics Who else? ~ P.S. Light, F. Couny, and F. Benabid. Single Mode Fiber (SMF) Photonic Bandgap Fiber (PBGF) Benabid’s group at University of Bath developed a method of splicing PBGF to SMF with a commercial splicer, using He and acetylene. The challenge with their project is keeping the pressure within the fiber constant during the splice. Our solution is making splices inside a vacuum chamber with a CO2 laser, and not using helium.

My Project Description Status of Project: - splices made in air; - new apparatus build, untested. My Goal: - make splices in vacuum. Results: - Improved splices in air. Major Challenges: - fiber slipping and sticking to clamps; - fiber length. Future Directions

Project Set-up

Project Set-up HeNe CO2 ZnSe Lens Clamps with Fibers Combiner

ZnSe Lens Lasers are passing through the center of the lens: Lasers are not centered:

Fiber Set-up Power (in mW) = 10 (Power dBm)/10 “Butt Coupled” fibers Fiber connected to Power meter Fiber connected to IR Laser ~2.3dBm (1.69 mW) Clamp on translation stage

Procedure Secure fibers in clamps Overlap lasers and align them onto fibers “Butt Couple” the fibers until maximum transmission obtained. Apply “Stuffing Stroke” ~ pushing fibers together until transmission drops ~3-4 dBm (fibers shrink during splice).

Splice at 3V for 1 minute or until transmission through fibers drops. Pre-heating for 20 sec. at 0.65V Activate CO2 laser using Labview program, and observe fiber transmission vs. time. Power Power Drop +1.95 dBm Calculate Splice Loss. -2.12dBm Splice complete -5.1 dBm Stuffing Stroke Time

Procedure (cont.) Check splice strength ~ “Break Radius.” BR = (L1+ L2) / (2*π) L1+ L2 = circumference

Challenges Problem #1: Fiber Slipping during Stuffing Stroke. Problem #2: Fragile splices. - sticky rubber on clamps - fiber length

ZnSe windows Translation Stage Fixed Clamp ZnSe Lens ZnSe Window

Results In Vacuum Chamber without ZnSe windows at atmospheric pressure Break Radius +0.76 cm Break Radius +1.37cm +0.27cm In Vacuum Chamber without ZnSe windows at atmospheric pressure Splice Loss -0.07 dBm => “Perfect” splice With ZnSe windows in Splice Loss +0.55 dBm + 2.235 dBm

Future of the project Splice SMF to SMF inside vacuum chamber with air in and lower power. Splice SMF to SMF with air pumped out. Splice SMF to PBGF and create acetylene cell.

Special Thanks =) Dr. Kristan Corwin Mr. Mike Wells LUMOS Group (Rajesh Thapa, Kevin Knabe, and Andrew Jones) Dr. Larry Weaver NSF/REU/Physics Department Aaron Pung, Matt Wood, and Greg Johnson