Low-loss and polarization insensitive 32 × 4 optical switch for ROADM applications

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Telecommunications

Background:

• Reconfigurable optical add-drop multiplexers (ROADMs) require integrated switches for enhanced flexibility and compactness.
• Achieving low insertion loss (IL) and polarization-dependent loss (PDL) in dense optical switches remains a significant challenge.

Purpose of the Study:

• To propose and demonstrate a novel 32x4 optical switch for ROADM applications.
• To utilize high-index doped silica glass (HDSG) for improved switch performance and integration.

Main Methods:

• The switch design incorporates 188 Mach-Zehnder Interferometer (MZI) elements and 618 waveguide-waveguide crossings with 3D structures.
• The device was fabricated using high-index doped silica glass (HDSG) for optical routing and switching functionalities.

Main Results:

• Achieved fiber-to-fiber loss below 2 dB for express channels at 1550 nm and below 3 dB across C and L bands.
• Demonstrated low loss (<3.5 dB at 1550 nm) for input channels to drop/add ports, with PDLs below 0.3 dB and crosstalk under -50 dB across C and L bands.

Conclusions:

• The proposed HDSG-based 32x4 optical switch offers a promising solution for compact and high-performance ROADM systems.
• The demonstrated low IL, PDL, and crosstalk meet the stringent requirements for advanced optical network applications.