Polarisation-independent optical circulator consisting of two fibre-optic polarising beam splitters and two YIG spherical lenses

摘要: A novel polarisation-independent optical circulator, which employs two fibre-optic polarising beam splitters and yttrium-iron-garnet (YIG) spherical lenses, is reported. The present structure has the advantage of low-loss splicing with other single-mode fibres. insertion loss was 2.5 dB at 1.30 ?m wavelength, almost independent incident polarisation angle. backward attenuation more than 18 dB.