32 channel WDM multiplexer with 1 nm channel spacing and 0.7 nm bandwidth

A high density WDM multiplexer capable of combining 32 channels spaced 1 nm apart onto a monomode fibre is reported. The multiplexer incorporates a microlens array to give a channel bandwidth of 0.7 nm. The wavelength range of operation is 1.5285 μm to 1.5595 μm, within the erbium fibre amplification range. The mean insertion loss over the 32 channels is 6.7 dB and the polarisation sensitivity is less than 0.7 dB.