External waveguide modulator operating at long wave infrared wavelength for free space optical communications

Free-space optical communications (FSOC) operating at long-wave infrared (LWIR) wavelengths are of particular interest due to a reduced sensitivity to atmospheric perturbations. However, their deployment requires the development of active and passive photonic components, and in particular of external modulators. To address this requirement, we developed an external modulator in a waveguide geometry based on the intersubband Stark effect in asymmetrical coupled quantum wells. Our device showed promising performances for phase and amplitude modulation as well as high speed operation capabilities. This demonstration paves the way to its future integration on a LWIR integrated photonic platform for LWIR FSOC applications.