Ultra-small silicon waveguide coupler switch using gap-variable mechanism.

Area of Science:

• Photonics
• Microelectromechanical systems (MEMS)
• Integrated Optics

Background:

• Optical waveguide couplers are essential components in photonic integrated circuits.
• Existing designs often lack compactness and efficient tunability for optical switching applications.

Purpose of the Study:

• To propose and demonstrate a compact optical waveguide switch utilizing a submicron-wide silicon waveguide coupler.
• To implement a variable gap mechanism for precise control over optical coupling.

Main Methods:

• Fabrication of freestanding silicon waveguides (400 nm width, 260 nm thickness).
• Integration of electrostatic comb-drive micro-actuators for variable gap control.
• Characterization of the coupler's performance by varying the waveguide gap.

Main Results:

• A compact switch (100 μm x 150 μm) was successfully fabricated.
• Decreasing the waveguide gap to 110 nm maximized drop port intensity and minimized through port intensity.
• An excellent extinction ratio of 17 dB was achieved with 300 nm waveguide displacement.

Conclusions:

• The proposed variable gap silicon waveguide coupler is a promising solution for compact and efficient optical switches.
• Electrostatic actuation provides effective control over optical coupling for switching functionalities.
• This technology has potential applications in advanced optical communication and signal processing systems.