Polarization insensitive interferometric wavelength converter with tensile strained InGaAs/InGaAsP MQW structure

Compact monolithic wavelength converters based on integrated three-port Mach-Zehnder interferometer (MZI) structure are realized for the first time with strongly reduced polarization sensitivity due to incorporation of tensile strained MQW active layers. The (InGaAs/InGaAsP) MQW structures are grown by LP MOVPE on full 2 inch n-InP substrates. By fine adjustment of tensile strain (varied between -0.3 and -0.45%) the optimum conditions to achieve equalized gain for TE and TM modes have been identified in accordance with modelling results. Assessment of static and dynamic all-optical wavelength conversion performance has been done for the MZI devices. Best results for TE/TM ratio are obtained for MZI wavelength converters with -0.34% tensile strain. A TE/TM ratio ⩽1 dB is achieved within a 20 nm wavelength conversion window. Penalty-free 2.5 Gbit/s polarization-insensitive all-optical wavelength conversion including extinction ratio improvement is demonstrated