Technical Information- High Power Fiber Optics

 

Fused Silica core optical fibers are capable of conducting very high laser energy under cw, average power and pulsed power levels. The actual allowable maximum energies are dependant on:
  • Fiber Quality
    Fused Silica (SiO2) with lowest contaminants has the highest power handling capabilities
  • Fiber face polishing at both the input and the output ends
    The polishing procedure must ensure that there are not any sub-surface flaws remaining from the grinding and polishing of the fiber ends. The final polishing step should use polishing particles that are a small fraction of the operating wavelength such as 0.1m.
  • Laser wavelength, intensity level and mode distribution
    The damage threshold of the fibers is less at shorter wavelengths.
  • Fiber mounting
    Fiber mounting at both the input and output should use thermally resistant buffers and epoxies to handle any thermal biuld up.
  • Cleanliness conditions
    Dust particles on the fiber face introduce hot-spots that may lead to catastrophic failures.
  • Fiber core diameter
    Power handling is proportional to core area, ie diameter squared. Maximum cw power handling is usually constrained by thermal consideration. With good polishing, alignment, and cleanliness conditions cw powers should be limited to about 126kW/cm2 at wavelengths of greater than 500 nm. Under very carefully controlled conditions including special cooling these levels can be increased by a factor of 3- 3.5.

 

Fiber Core/CW Power Limitation

 

FIBER CORE DIAMETER
(m)
CW POWER LIMITATION
(watts)

50
 
2.0
 
100
 
8.0
 
200
 
32
 
400
 
128
 
600
 
288
 
1000
 
800
 

High Power Laser Transmission Cables