Combining Four Gaussian Lasers Using Silicon Nitride MMI Slot Waveguide Structure.

Area of Science:

• Photonics
• Optical Engineering
• Materials Science

Background:

• High-speed transceivers (>200 Gb/s) require increased optical power to mitigate losses, often necessitating larger components or complex lasers.
• Existing solutions like high-power lasers present challenges for photonic integrated circuits, including cost and increased system noise due to nonlinear effects.

Purpose of the Study:

• To propose and analyze a novel silicon nitride slot waveguide-based 4x1 power combiner for enhancing optical power in high-speed communication systems.
• To demonstrate a cost-effective and efficient method for increasing optical power levels on photonic chips.

Main Methods:

• Utilized a multimode interference (MMI) approach within a silicon nitride slot waveguide structure.
• Employed the full-vectorial beam propagation method (FV-BPM) for combiner design and analysis.
• Analyzed key parameters using Matlab script codes and simulated back reflection (BR) with the finite difference time-domain (FDTD) method.

Main Results:

• Achieved high combiner efficiency of at least 98.2% over the O-band spectrum.
• Demonstrated efficient light coupling propagation within a short distance of 28.78 μm.
• Obtained a low back reflection (BR) of 40.15 dB, ensuring signal integrity.

Conclusions:

• The proposed silicon nitride slot waveguide power combiner effectively increases optical power for photonic chips.
• This technology offers a viable solution for combining multiple coherent sources in the O-band range for high-speed data transmission.
• The low back reflection and high efficiency make it suitable for advanced photonic integrated circuits.