Optical reflection filters based on intracavity quantum well polarisation convertors

The design and analysis of a guided-wave optical reflection filter, based on the use of a multiple quantum well polarisation convertor in an intracavity geometry, are reported. It is shown that quantum well dispersion and excitonic absorption in GaAs/AlGaAs quantum well structures can be used to produce filter linewidths and peak reflectances of <1 nm and approximately 95%, respectively, in the centre wavelength band of 865-885 nm. The use of dispersion engineering to tailor the filter response, via the quantum well parameters, is also described. Such optical filters should find widespread application as wavelength-selective components in fibreoptic network and communication systems.