High-efficiency broadband fiber-to-chip coupler using a 3D nanoprinting microfiber

Area of Science:

• Photonics and Optical Engineering
• Nanofabrication and Nanotechnology
• Integrated Optics

Background:

• Efficiently coupling light between optical fibers and integrated photonic circuits is crucial for optical communication and sensing.
• Existing methods often face challenges with alignment, loss, and fabrication complexity.
• Silicon nitride (SiN) waveguides offer excellent optical properties for integrated photonic devices.

Purpose of the Study:

• To propose and simulate a novel microfiber coupler fabricated using 3D nanoprinting for efficient light coupling.
• To achieve high coupling efficiency and a wide operational bandwidth between a tapered optical fiber and an inverted tapered SiN waveguide.
• To demonstrate a low-loss light transmission pathway through a complex microfiber structure.

Main Methods:

• Utilizing 3D nanoprinting lithography to fabricate a microfiber coupler with a tapered cladding cap, S-bend, and straight section.
• Employing adiabatic coupling principles for light transfer from the tapered fiber to the microfiber.
• Leveraging evanescent field coupling for light transfer from the microfiber to the SiN waveguide.
• Performing optical simulations to evaluate coupling efficiency and bandwidth.

Main Results:

• Achieved a simulated transverse electric (TE) mode coupling efficiency of approximately 97% at a wavelength of 1542 nm.
• Demonstrated a wide operational bandwidth of approximately 768 nm, based on the 1-dB cutoff criterion.
• The designed microfiber structure facilitates low-loss light transmission.

Conclusions:

• The proposed 3D nanoprinted microfiber coupler offers a promising solution for efficient fiber-to-waveguide interfacing.
• The method enables high-performance optical coupling with a broad wavelength range, suitable for various photonic applications.
• This fabrication technique advances the development of compact and efficient integrated photonic devices.