Low-loss and low-crosstalk silicon triplexer based on cascaded multimode waveguide gratings

Area of Science:

• Photonics
• Integrated Optics
• Materials Science

Background:

• Wavelength-division multiplexing (WDM) is crucial for high-capacity optical communication.
• On-chip optical filters are essential components for WDM systems.
• Existing triplexers often face challenges with insertion loss and channel crosstalk.

Purpose of the Study:

• To design and fabricate a low-loss, low-crosstalk silicon triplexer.
• To enable efficient multiplexing of 1310, 1490, and 1550 nm wavelength channels.
• To demonstrate flat-top spectral responses for improved signal integrity.

Main Methods:

• Utilizing cascaded multimode-waveguide-grating (MWG)-based filters.
• Integrating MWGs with two-mode (de)multiplexers on a silicon platform.
• Experimental characterization of spectral response, bandwidth, insertion loss, and crosstalk.

Main Results:

• Achieved flat-top spectral responses for all three wavelength channels.
• Measured 3 dB bandwidths of 89 nm (1310 nm), 19 nm (1490 nm), and 7 nm (1550 nm).
• Demonstrated excess losses below 1 dB and crosstalk levels of -36 to -27 dB (1490 nm) and -32 to -28 dB (1550 nm).

Conclusions:

• The proposed silicon triplexer effectively meets the requirements for WDM optical systems.
• The device exhibits excellent performance in terms of loss, crosstalk, and spectral flatness.
• This technology holds promise for advancing integrated photonic devices for optical communications.