Compact and low power operation optical switch using silicon-germanium/silicon hetero-structure waveguide

Area of Science:

• Photonics and optoelectronics
• Semiconductor device physics

Background:

• Optical switches are crucial components in modern communication networks.
• Existing silicon-based optical switches often face limitations in terms of power consumption and device size.
• Carrier-plasma-induced phase shifting offers a potential mechanism for low-power optical modulation.

Purpose of the Study:

• To propose and demonstrate a novel silicon-based optical switch utilizing a silicon-germanium (SiGe) / silicon (Si) heterostructure.
• To investigate the performance of a carrier-plasma-induced phase shifter in a Mach-Zehnder optical switch configuration.
• To evaluate the switching power and switching time of the fabricated device.

Main Methods:

• Fabrication of a Mach-Zehnder optical switch incorporating a SiGe/Si heterostructure waveguide core.
• Utilizing the carrier-plasma effect in the SiGe waveguide for phase shifting.
• Characterization of the optical switch's switching power and switching time under different driving conditions.

Main Results:

• The fabricated optical switch demonstrated a low switching power of 1.53 mW.
• A compact phase shifter length of 250 μm was achieved.
• Switching times of less than 4.6 ns (square waveform) and 1 ns (pre-emphasis) were recorded.

Conclusions:

• The proposed SiGe/Si waveguide structure effectively confines carriers, enabling efficient phase shifting.
• The developed optical switch exhibits excellent performance metrics, including low power consumption and high speed.
• This SiGe/Si heterostructure technology is highly promising for the development of next-generation compact and low-power active photonic devices.