Highly linear and efficient phase modulators based on GaInAsP-InP three-step quantum wells

Highly linear and efficient phase modulators based on three-step quantum wells are reported. The spatial separation of electron and hole wave functions in the three-step quantum well leads to enhancement of the linear electro-optic component. In parallel, the quadratic electro-optic component is suppressed using a method based on tailored doping profile. Measured modulation efficiency is 48°∕mm V, and the ratio of linear to quadratic components of the phase modulation is 640 at λ=1560nm. The efficiency is similar to the best reported values for semiconductor modulators at this wavelength, while the linearity is more than one order of magnitude higher.