To increase the efficiency of light
coupling we can use fiber launch system, which uses a microscope objective lens
to focus the light down to a fine point.
We have two types op coupling
technique. They are direct coupling and Lens coupling.
 |
|
Direct
coupling
|
In this system
coupling efficiency is low because the full strength of the out put light is
not going through the fiber.
 |
| Lens coupling |
In lens coupling the light coupling
efficiency is high. Because two lenses are can be used to focus light. That
means whole source light is going through the fiber. The efficiency is more
than 70% percent.
