Mach-Zehnder silicon-photonic switch with low random phase errors.

Area of Science:

• Photonics
• Integrated Optics
• Semiconductor Devices

Background:

• Mach-Zehnder switches (MZSs) are crucial for optical switching.
• Random phase errors limit the performance of silicon photonic switches.
• Conventional designs face challenges in fabrication tolerance and power consumption.

Purpose of the Study:

• To propose and demonstrate a silicon photonic switch with significantly reduced random phase errors.
• To enhance the fabrication tolerance of thermo-optic Mach-Zehnder switches.
• To decrease power consumption for phase error compensation in integrated photonic devices.

Main Methods:

• Designing and fabricating over one hundred 2x2 thermo-optic Mach-Zehnder switches using a 180 nm CMOS foundry process.
• Incorporating judiciously widened and shortened phase shifter waveguides.
• Characterizing fabricated switches on 14 silicon chips to evaluate phase errors.

Main Results:

• Switches with 2 µm widened phase shifters exhibited mean and standard deviation of random phase errors less than a third of conventional 0.45 µm single-mode designs.
• Demonstrated improved fabrication tolerance for silicon thermo-optic switches.
• Achieved considerable reduction in power consumption for phase error compensation.

Conclusions:

• The proposed method effectively reduces random phase errors in silicon photonic switches.
• The technique enhances fabrication tolerance, enabling scalability for N×N switches.
• This approach is generalizable to other phase-sensitive integrated photonic devices.