Gain: Input & output Photon relation…making it more simple.

What is a 30 dB gain means???

Puzzled..Earlier I use to be the same  but its really simple to understand.It means:-

For every input PHOTON there will be 1000 PHOTON’s at output. That’s what Gain is..

              X dB is 10^x/10

^{You can verify the same with above formula…Make things Simpler.}