Inverse designed photonic crystal de-multiplex waveguide coupler

Area of Science:

• Photonics
• Optical Communications
• Nanophotonics

Background:

• Photonic crystals offer unique light manipulation properties.
• Efficient wavelength division multiplexing is crucial for optical networks.
• Compact and high-performance diplexers are needed for integrated photonic circuits.

Purpose of the Study:

• To design and demonstrate a two-dimensional photonic crystal diplexer integrated with a waveguide coupler.
• To achieve efficient separation of optical signals at communication wavelengths (1.50 µm and 1.55 µm).
• To optimize the device for high coupling efficiency and low crosstalk within a small footprint.

Main Methods:

• Computer-generated design using an inverse design process.
• Device fabrication within a 5 µm x 5 µm area.
• Characterization of optical performance, including crosstalk and coupling efficiency.

Main Results:

• A functional diplexer was designed for 1.50 µm and 1.55 µm wavelengths (50 nm channel spacing).
• Crosstalk levels were suppressed below 40 dB for both channels.
• Coupling efficiencies approaching 80% were achieved for both communication channels.

Conclusions:

• The proposed inverse design approach enables the creation of high-performance photonic crystal diplexers.
• The demonstrated device shows significant potential for integrated optical communication systems.
• The compact size and excellent performance metrics make it suitable for advanced photonic integrated circuits.