About the modal noise of optical fibers

[Joan Guarro Flo]

Bonsoir Christian,

I have read a lot about the problem of modal noise and I'm trying to apply solutions.
Since I have the echelle under the support of the equatorial mount, the optical fiber length is only 2 meters.

My fiber is a FG050LGA (Low OH), your is a High OH, apart from the different spectral response, is there any other difference?
The telescope is a SC of F / 10, it takes it to F / 6.3 (approx. A bit too high), with a ALAN GEE MARK II.

I have built this agitator in Fig.3, which I could test last night with Regulus, the agitated graphics improves, but I think that it does not do enough.
 Perhaps a solution would be to use an optical fiber of 5 meters in length and place another agitator. Now with 2 meters I can not put any more.

What is your opinion ? What do you think I have to do to get better results?

Another question, if instead of shaking the fiber, they would be made a series of loops similar to Fig.4. Could it work?

Bien amicalement, Joan.