Thanks a million Bob,
about the method vibration modulates the light intensity:
I want to use FBG (Fiber Bragg Grating) that its Bragg wavelength suffer shift when strain is applied to. since the vibration in fact is a dynamic strain, so with vibration the Bragg wavelength will change in time...
Dear Bob;
thanks for your attention...
I mean the modulating frequency bandwidth. e.g. the second page of the attached file mention the Low and high Cut-off Frequency.
Or: Please see the "bandwidth" in :
http://qphotonics.com/catalog/Fiber-coupled-InGaAs-PIN-photodiode-p-180.html
this point...
I'm trying to design a fiber optic sensor to sense vibration via intensity modulation.
I'm new in this field and i don't know whether I can use a PIN photodetector for low frequency or not... what's the bandwidth of a PIN Photodetector? Does it mean its responsivity is limited in low frequency...