1. Laser range finder. I've designed them; it's irritating to have to have a 150-250V power supply in a little handheld device. Noisy, too.
2. Night vision. Think night amplification devices as cheap as cameras are now.
Bring on the future.
Imagine NV that is clear and as focused as daylight vision. No more fuzzy greenish images...........................and light weight, runs on two AA batteries....................
Yes, OTDRs would benefit also assuming the gain is high enough.