Efficient fiber-coupled system based on coreless fiber end-face aspherical microlens

To enhance the applicability of non-contact optical fiber interconnects, a coreless optical fiber (COF) segment is spliced onto the tip of a single-mode fiber (SMF). Subsequently, an aspherical microlens (AM) is precisely fabricated at the COF end through grinding and polishing processes. This design aims to significantly improve the coupling efficiency (CE) of the optical fiber interconnect, addressing critical challenges in high-performance optical systems. First, the Gaussian beam propagation matrix is used to analyze the transmission characteristics of light within the aspheric microlens. Then, an optical coupling model is developed to investigate the effects of parameters such as the incident light wavelength, positional offset, angular deviation, lens diameter, lens curvature radius, refractive index, and temperature on CE. Finally, an experimental platform is constructed to validate the simulation results. The simulation results show that the CE of design and fabrication of the fiber tip microlens can reach to 92% and it shows universality for incident light wavelengths. Additionally, it obtains generous axial coupling tolerances, reducing the requirements of the assembly process.