Asymmetric Ge/SiGe coupled quantum well modulators

We design and demonstrate an asymmetric Ge/SiGe coupled quantumwell (CQW) waveguide modulator for both intensity and phase modulation with a low bias voltage in silicon photonic integration. The asymmetric CQWs consisting of two quantum wells with different widths are employed as the active region to enhance the electro-optical characteristics of the device by controlling the coupling of the wave functions. The fabricated device can realize 5 dB extinction ratio at 1446 nm and 1.4 x 10(-3) electrorefractive index variation at 1530 nm with the associated modulation efficiency V pi L pi of 0.055 V cm under 1 V reverse bias. The 3 dB bandwidth for high frequency response is 27 GHz under 1 V bias and the energy consumption per bit is less than 100 fJ/bit. The proposed device offers a pathway towards a low voltage, low energy consumption, high speed and compact modulator for silicon photonic integrated devices, as well as opens possibilities for achieving advanced modulation format in a more compact and simple frame.

Automated summary

The study introduces an asymmetric Ge/SiGe coupled quantumwell (CQW) waveguide modulator for both intensity and phase modulation in silicon photonic integration. By controlling the coupling of the wave functions, the fabricated device achieves low energy consumption, high speed, and compact size.