Polarisation-insensitive modulator and influence of propagation direction on bulk electroabsorption

The authors report measurements on electroabsorption in deep ridge waveguide structures. The polarisation sensitivity is found to depend not only on the detuning but also on the propagation direction. In an InGaAsP/InP double heterostructure, polarisation insensitivity is obtained over a large detuning range (80 nm) for propagation along the [-110] direction