Tunable surface-normal modulators operating near 1550 nm with a high-extinction ratio at high temperatures

We present high-performance surface-normal modulators based on unique properties of stepped quantum wells at an eye-safe wavelength of 1550 nm. Fabricated devices show higher efficiency and a 7-dB higher extinction ratio compared with devices with coupled quantum-well active layers. Moreover, the energy band edge of the device can be tuned over 70 nm while maintaining a 3-dB modulation depth. Such a wide tuning range eliminates the need for a thermoelectric cooler and is a critical advantage for many applications such as unmanned aerial vehicles and dynamic optical tags. The devices show good performance up to the maximum measured temperature of 70°C.