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 mu m to 1.5595 mu m, 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.