A Novel High-Speed and Wavelength Insensitive Y-Branch Modulator with Reduced and Controllable Chirp

We propose and demonstrate a novel high-speed and wavelength insensitive Y-branch Modulator in InGaAsP multiple-quantum-wells that exhibit negligible chirp and is also suitable for achieving controllable chirp. We apply a voltage on one arm of the Y-branch to raise its refractive index allowing the light to switch to this arm which then results in light modulation in the other unbiased arm. The modulated light in the unbiased arm experiences little phase change and therefore exhibits negligible chirp. We demonstrate that the chirp in the modulated light in the unbiased port is approximately 10 times lower than that of typical electroabsorption modulators. Biasing both arms in the push-pull configuration to change index in opposite direction in the two arms will allow one to tune the chirp of the modulated light from a single port to any desired value. This modulator is also fairly wavelength insensitive because light switching mechanism is based on adiabatic modal evolution.