Robust InP/InGaAsP Polarization Rotator Based on Mode Evolution

InP-based polarization manipulating devices are attracting continuous interest to realize compact polarization multiplexed transceivers with monolithically integrated active components. Here, we propose and experimentally demonstrate a novel type of monolithic InP polarization rotator (PR) based on a tapered half-ridge structure. Owing to the principle of mode-evolution-based adiabatic rotation of the polarization axis along propagation, the demonstrated device inherently exhibits excellent robustness against fabrication errors. Error-tolerant conversion with an efficiency over 97% is obtained experimentally across the entire
C
-band. With the simple self-aligned process and a thick InP upper cladding, the demonstrated device would be suitable for low-loss integration with other InP-based active waveguide components, such as lasers, amplifiers, and modulators.