Er3+ doped fibre pre-amplifier with subsidiary EDF for application in WDM systems using two separate wavelength bands of 1.53 and 1.55 µm
An economical optical amplifier circuit for a pre-amplifier of multi-channel WDM systems, using two separate wavelength bands of 1.53 and 1.55 µm, is proposed. The optical sensitivity of the receiver between the two bands is balanced by installing a subsidiary Er3+ doped fibre (EDF) in the 1.55 µm path. Curves of bit error rates at 10 Gbit/s for a six-channel receiver, two channels in the 1.53 µm band and four channels in the 1.55 µm band, form a bunch of similar lines without any error floor.