1. 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

2. 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.

3. 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

4. Project Set-up

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

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

7. 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

8. 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).

9. 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

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

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

12. ZnSe windows
Translation Stage Fixed Clamp
ZnSe Lens
ZnSe Window

13. Results In Vacuum Chamber without ZnSe windows at atmospheric pressure
Break Radius cm
Break Radius cm cm
In Vacuum Chamber without ZnSe windows at atmospheric pressure
Splice Loss
-0.07 dBm => “Perfect” splice
With ZnSe windows in
Splice Loss dBm dBm

14. 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.

15. 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