Suppression of modal birefringence in InP-InGaAsP waveguides through use of compensated tensile strain

We show that the modal birefringence of InP-based planar guides can be significantly reduced through the action of compensated tensile strain. By using low bandgap tensile and higher bandgap compressive layers, the material birefringence of the former may be made to dominate and provide significant modal birefringence suppression. The suppression attained is much greater than can be achieved through the application of tensile strain alone.