Smart Dynamic Wavelength Equalizer with On-Chip Spectrum Analyzer

A fully automated dynamic wavelength equalizer with fast feedback is presented, consisting of a planar optical circuit made in silica and a minimal amount of secondary elements. An on-chip monitor and a single optical diode serve as a low-cost, fast, built-in optical spectrum analyzer, used to feedback control the device. The system is demonstrated by flattening the amplified spontaneous emission spectrum of an erbium-doped fiber amplifier from 4.0 dB to within 0.55 dB peak-to-peak in less than a second.