Zero-gap directional coupler switch integrated into a silicon-on insulator for 1.3-microm operation

Area of Science:

• Photonics
• Materials Science
• Electrical Engineering

Background:

• Silicon-on-insulator (SOI) technology offers advantages for photonic integrated circuits.
• Directional coupler switches are fundamental components in optical communication systems.
• Efficient and low-loss optical switching is crucial for high-speed data transmission.

Purpose of the Study:

• To investigate a zero-gap directional coupler switch fabricated using silicon-on-insulator (SOI) technology.
• To leverage dual-mode interference and free-carrier plasma dispersion effects for optical switching.
• To characterize the performance of the SOI switch, including insertion loss, crosstalk, and response time.

Main Methods:

• Fabrication of the SOI switch using silicon and silicon dioxide thermal bonding and backpolishing.
• Utilizing potassium hydroxide anisotropic etching for SOI substrate preparation.
• Employing the dual-mode interference principle and free-carrier plasma dispersion effect for switching.
• Experimental measurement of insertion loss, crosstalk, and response time at a 1.3 micrometer wavelength.

Main Results:

• The SOI zero-gap directional coupler switch demonstrated excellent performance.
• Measured insertion loss was less than 4.81 dB.
• Exceptional crosstalk suppression of 218.6 dB was achieved.
• A fast response time of approximately 210 ns was recorded at a switching voltage of 0.91 V.

Conclusions:

• The developed SOI directional coupler switch shows high potential for optical communication applications.
• The combination of SOI technology, dual-mode interference, and free-carrier effects enables efficient and low-voltage optical switching.
• The achieved performance metrics, particularly low crosstalk and fast response time, are significant for advanced photonic integrated circuits.