Optical coupler with optical isolator independent of polarisation

摘要

The optical isolator (8) serves to prevent the output of an interfering light at the incident end. The output ends of the two input fibres (1, 2) may be fused together along a predetermined length. In one version there are condensing lenses (10, 11) on either side of the isolator; in another there is one condensing lens prior to the isolator. The output fibre (3) may be connected to an erbium doped fibre and one input may be an excitation light while the other is a signal to be amplified by induced emission.