Polarization-independent switching operation in directional coupler using tensile-strained multi-quantum well

Polarization-independent switching operation in a multi-quantum well directional coupler is obtained for the first time, with a bar-state crosstalk of -12 dB. By introducing tensile strain in an InGaAs-InP multi-quantum well, polarization-independent switching voltage is as small as 3 V, with the coupling length being 1.2 mm. The cross-state crosstalk that is obtained at zero-applied voltage, is less than -8 dB with respect to TE and TM polarized lights.>