MOVPE growth of ternary and quaternary tensile strained MQW structures for polarization insensitive devices

Abstract

Devices for future all-optical network systems will have a strong requirement for polarization independent operation, which can be achieved by introducing biaxially tensile strain into MQW active regions. We report on InP based low pressure MOVPE growth of MQW structures for 1.55 μm wavelength with tensile strained InGaAs and InGaAsP wells and lattice matched InGaAsP barrier layers. Taking into account measurement results from X-ray and PL together with theoretical evaluations we were able to grow polarization insensitive device structures. For all-optical wavelength converters we used MQW stacks with 5 tensile strained ternary wells and achieved λ conversion with a polarization dependence of less than 1 dB. Using quaternary wells a polarization insensitive electroabsorption modulator was realized. The residual polarization dependence is < 0.4 dB for 1550 nm and < 1 dB in the wavelength range from 1540 to 1560 nm (extinction ratio 10 dB).