Abstract: An optical multiplexer device comprising: a first optical input channel; a second optical input channel; an optical output channel; a first series of polarization manipulation elements inconnected to the first and second input channel, the elements manipulating the polarization state of light emitted from either the first or second input channel; a wavelength selective filter adapted to transmit first predetermined wavelengths and reflect second predetermined wavelengths emitted from the first and second optical channel; a second series of polarization manipulation elements for manipulating the first predetermined wavelengths; wherein input light from the second optical input channel having third predetermined range of wavelengths is combined with light emitted from the first optical input channel at the optical output channel.