Crossing-free on-chip 2  ×  2 polarization-transparent switch with signals regrouping function

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Telecommunications

Background:

• Polarization-division multiplexing (PDM) is crucial for increasing optical communication capacity.
• Existing PDM switches often suffer from high insertion losses and complexity due to waveguide crossings.
• Efficient and flexible switching of PDM signals is essential for advanced optical networks.

Purpose of the Study:

• To propose and demonstrate an on-chip 2x2 polarization-transparent switch.
• To handle two-group PDM signals simultaneously.
• To reduce insertion losses and device complexity compared to conventional PDM switches.

Main Methods:

• Introduction of a polarization-transparent power splitter/combiner (PPS/PPC) to avoid waveguide crossings.
• Independent switching and routing of each input polarization tributary.
• Experimental characterization of the switch's performance, including polarization extinction ratio and insertion loss.

Main Results:

• Demonstration of an on-chip 2x2 polarization-transparent switch.
• Achieved a polarization extinction ratio greater than 15 dB.
• Observed reasonable insertion losses with less than 1 dB power penalties for all measured paths, indicated by clear eye diagrams.

Conclusions:

• The proposed PPS/PPC based switch effectively reduces insertion losses and complexity.
• The switch enables both basic switching and precise four-channel signal regrouping for dual-group PDM signals.
• This technology offers a complete and non-redundant switching functionality for optical communication systems.