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 0.1µm.
-
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
(µm)
|
CW POWER LIMITATION
(watts)
|
|
|
50
|
|
2.0
|
|
|
100
|
|
8.0
|
|
|
200
|
|
32
|
|
|
400
|
|
128
|
|
|
600
|
|
288
|
|
|
1000
|
|
800
|
|
High Power Laser Transmission Cables
|
