Phase-shifter using submicron silicon waveguide couplers with ultra-small electro-mechanical actuator

Area of Science:

• Photonics
• Optical Engineering
• Microelectromechanical Systems (MEMS)

Background:

• Phase shifters are essential components in optical waveguide circuits, particularly for interferometers.
• Achieving a significant phase shift within a confined space presents a notable engineering challenge.

Purpose of the Study:

• To design and fabricate a variable phase shifter for silicon waveguide circuits.
• To demonstrate a compact device capable of generating a large phase shift.

Main Methods:

• Designed a phase shifter utilizing a freestanding submicron-wide silicon waveguide and a silicon comb-drive actuator.
• Fabricated the device using silicon micromachining techniques.
• Integrated the phase shifter into a Mach-Zehnder interferometer for performance evaluation.

Main Results:

• Achieved a phase shift of 3.0π at a displacement of 1.0 µm with an applied voltage of 31 V.
• The fabricated device has compact dimensions of 50 µm wide and 85 µm long.
• The device operates as a delay-line, varying the total optical path length.

Conclusions:

• The developed silicon waveguide phase shifter is effective for generating large phase shifts in compact optical circuits.
• The micromachined device offers a promising solution for miniaturizing optical components in interferometric applications.