single mode fiber lasers

carl_townshend · ‎01-22-2009

Hi all, I know with multi mode fiber we can see the laser at the end, should this be true with single mode also ?

scottmac · ‎01-22-2009

Carl:

DO NOT UNDER ANY CIRCUMSTANCES LOOK INTO A FIBER OPTIC END UNLESS YOU KNOW, FOR A FACT, THAT IT IS DE-ENERGIZED!!!!!!!!!!!!!!!!!!!!!

NO kidding, no joke. Doing so can cost you your eyesight.

Single-mode uses wavelengths you cannot see, but are extremely strong and *WILL* burn a permanent line into your retina ... no recovery.

Even with Multimode and visible wavelengths, it is extremely bad practice to look into a fiber optic end ... unless you can see both ends, and neither are connected.

DO NOT, DO NOT, DO NOT look into a fiber optic end.

This also applies to fiber optic equipment (potentially live GBICS, SFPs, or other optical ports. Any unused ports should be plugged, even if the equipment automatically powers the port down on loss of signal ... don't risk your eyesight on some programmer's coding ability ... you know how things go with bugs and other "undocumented features."

Good Luck

Scott

viyuan700 · ‎01-22-2009

As already mentioned in other post singlemode are working on 1310nm & 1550nm range which are way beyond the visible spectrum (380-750nm).

In Multimode you can see those which operates at 850 nm close to red wavelngth.

Have you seen light at 1310nm range in Multimode?

scottmac · ‎01-22-2009

Red is ~650nm.

850nm is near-IR (not visible)

viyuan700 · ‎01-22-2009

"Red is ~650nm" Are you sure red is ONLY ~650nm? As far as i know there is no rule (like 2+2=4)that ~650nm is only red.

Is 200 near to 100 or 300?

scottmac · ‎01-22-2009

Yes. I'm sure. Center red is 650 nanometers (6500 angstroms).

649 is trending to blue, and 651 is on the way to infrared/non-visible.

850nm is not visible.

What's your point?