Rapid fabrication of sub-micron scale functional optical microstructures on the optical fiber end faces by DMD-based lithography.

The rapid development of optical fiber application systems puts forward higher requirements for the miniaturization and integration of optical fiber devices. One promising solution is to integrate diffractive optical microstructures on the end faces of optical fibers. However, rapid microfabrication on such tiny and irregular substrates is a challenge. In recent years, Femtosecond laser polymerization technology has become an effective solution to the challenge, which can be flexibly applied for the fabrication of complex 3D microstructures with ultra-high resolution. When the demand for the lithography resolution is not very high, other microfabrication methods with a lower technical threshold may be developed for achieving a balance between fabrication precision, cost and efficiency. In this paper, we report a Digital Micromirror Device (DMD) based lithography method dedicated to the fabrication of functional optical microstructures on the optical fiber end faces. Especially, it's also applicable to single-mode fibers (SMFs). By the projection via a 40x objective lens, the fabrication resolution of 0.405 μm was achieved within an exposure area of 209.92 μm × 157.44 μm. We evaluated the microfabrication results by the photomicrographs and the optical diffraction modulation effects of the functional optical microstructures. This method provides a new idea for fabricating both hybrid optical fiber devices and SMF devices, and it may be an alternative method for resolving the conflict between the precision, the cost and the efficiency.