A MEMS grating modulator with a tunable sinusoidal grating for large-scale extendable apertures.

Area of Science:

• Optoelectronics
• MEMS devices
• Nanophotonics

Background:

• Microelectromechanical system (MEMS) grating modulators offer beam steering but face limitations in optical efficiency and aperture size.
• Existing designs utilize movable ribbons, leading to fabrication complexities and cost issues compared to micromirror devices.

Purpose of the Study:

• To develop a MEMS grating modulator with enhanced aperture scalability and high optical efficiency.
• To address the limitations of conventional MEMS modulators for advanced optical applications.

Main Methods:

• The study employs a tunable sinusoidal grating design with broadside-constrained continuous ribbons, moving away from end-constrained ribbons.
• This approach facilitates improved scalability and an increased fill factor for the grating surface.

Main Results:

• A MEMS grating modulator with a 30x30mm aperture and up to 90% optical efficiency was experimentally demonstrated.
• The device achieved a 1.1μs mechanical settling time, >20dB extinction ratio, and >95% dynamic modulation contrast at 250kHz.
• Broad wavelength modulation (635-1700nm) and a wide field of view (±30°) were achieved.

Conclusions:

• The developed MEMS grating modulator offers significant improvements in aperture size and optical efficiency.
• It shows strong potential for high-speed light attenuation and modulating retroreflector free-space optical (MRR-FSO) communication.
• This technology paves the way for future high-speed, energy-efficient, and cost-effective communication networks.