You also need to keep in mind that if the distance is to short and the attenuator is to close to the transmitter, the reflected light off the attenuator will be directed back towards the Tx laser. Which will also blow your transmitter. Optimal Rx lev...

In telecom dark fiber does not mean "no light" it just means that its leased to another carrier for whatever their use maybe. Its considered "Dark" because we do not see the traffic riding the fiber we are leasing to a customer. Meaning we lease the ...