Dynamic gain equalisation filter based on integrated optical transversal filter with asymmetric combiner

A compact dynamic gain equalisation filter on a silica-based planar lightwave circuit has been fabricated. The filter is based on the authors´ newly developed optical transversal filter that uses an asymmetric combiner. This device flattened the amplified spontaneous emission spectrum of an erbium-doped fibre amplifier to a ripple of ∼1 dB over a wavelength range of 30 nm.