Polarization-insensitive mode-independent thermo-optic switch based on symmetric waveguide directional coupler

Area of Science:

• Photonics and Optical Engineering
• Materials Science for Optoelectronics

Background:

• Mode-division multiplexing (MDM) systems require efficient mode-selective switching.
• Existing thermo-optic switches often lack mode independence or have limited performance.

Purpose of the Study:

• To design and fabricate a mode-independent thermo-optic switch.
• To demonstrate simultaneous switching of multiple modes in parallel waveguides.
• To evaluate the performance of the switch for optical communication applications.

Main Methods:

• Utilized a symmetric directional coupler with two parallel two-mode waveguides.
• Fabricated the device using polymer materials.
• Characterized switching power, extinction ratios across the C-band, and switching time.

Main Results:

• Achieved simultaneous switching of fundamental and higher-order modes.
• Measured extinction ratios >18 dB (fundamental) and >13 dB (higher-order mode).
• Demonstrated a switching time of approximately 1 ms with low switching power (128 mW).

Conclusions:

• The proposed thermo-optic switch is mode-independent and performs effectively.
• The device exhibits excellent extinction ratios and fast switching speeds.
• This technology is suitable for reconfigurable mode-division-multiplexing transmission systems.