1 × 2 mode-independent polymeric thermo-optic switch based on a Mach-Zehnder interferometer with a multimode...

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Optical Switching Technologies

Background:

• Mode-division multiplexing (MDM) systems offer enhanced data capacity but require mode-independent optical components.
• Existing thermo-optic switches often suffer from mode-dependent performance, limiting their application in advanced optical networks.

Purpose of the Study:

• To design and demonstrate a broadband 1x2 mode-independent thermo-optic (TO) switch.
• To achieve mode-independent transmission and switching for E11 and E12 modes within the C+L band.
• To validate the device's performance for potential use in reconfigurable MDM systems.

Main Methods:

• Utilized a Mach-Zehnder interferometer (MZI) with a Y-branch power splitter and a multimode interferometer (MMI) coupler for mode insensitivity.
• Optimized waveguide structural parameters for mode-independent operation.
• Fabricated the device on a polymer platform using ultraviolet lithography and wet-etching.

Main Results:

• Demonstrated mode-independent switching for E11 and E12 modes across a broadband wavelength range (1530-1610 nm).
• Achieved high extinction ratios (>13.3 dB for E11, >13.1 dB for E12) with low driving power (5.9 mW).
• Measured switching times under 840 µs with insertion losses of 11.7 dB (E11) and 14.2 dB (E12) at 1550 nm.

Conclusions:

• The developed thermo-optic switch exhibits excellent mode-independent performance, suitable for broadband applications.
• The device maintains input mode content at the output, a critical feature for MDM systems.
• This technology paves the way for efficient reconfigurable MDM systems, enhancing optical communication capabilities.