abbydee75
Mechanical
- Feb 5, 2007
- 2
Hi, we've got a device with an optical transmission line made as follows:
1) an infrared transmission device containing a led surrounded by either Dow Corning Sylgard or Araldite D and a 0.4mm thick PES disk as "external window"
2) a 0.5mm free air path
3) a receiver with the same architecture of the tx
We must do a thermical cycle to validate the product: 3h@-20°C, then 3h@+70°C, all this for 2 times.
What happens is this:
a) without thermical cycle our electronics has a gain X on the optical amplifier
b) with Sylgard we see that after the first -20°C the gain need to be lowered (i.e. the optical attenuation diminish), after +70°C the effect goes on the same direction but is less important and another -20 does almost nothing so we can say that the first cycle tends to improve and stabilize the path loss
c) with Araldite D the effect is more intense and after every step, both -20 and +70, ther is a substantial improvement without stabilization.
We made the cycle on some specimens without filler and saw no variations at all, so it must be the polymer that makes the difference.
Can anyone please suggest an interpretation of this?
1) an infrared transmission device containing a led surrounded by either Dow Corning Sylgard or Araldite D and a 0.4mm thick PES disk as "external window"
2) a 0.5mm free air path
3) a receiver with the same architecture of the tx
We must do a thermical cycle to validate the product: 3h@-20°C, then 3h@+70°C, all this for 2 times.
What happens is this:
a) without thermical cycle our electronics has a gain X on the optical amplifier
b) with Sylgard we see that after the first -20°C the gain need to be lowered (i.e. the optical attenuation diminish), after +70°C the effect goes on the same direction but is less important and another -20 does almost nothing so we can say that the first cycle tends to improve and stabilize the path loss
c) with Araldite D the effect is more intense and after every step, both -20 and +70, ther is a substantial improvement without stabilization.
We made the cycle on some specimens without filler and saw no variations at all, so it must be the polymer that makes the difference.
Can anyone please suggest an interpretation of this?