High Q‐Factor Polymer Microring Resonators Realized by Versatile Damascene Soft Nanoimprinting Lithography

High‐quality‐factor microring resonators are highly desirable in many applications. Fabricating a microring resonator typically requires delicate instruments to ensure a smooth side wall of waveguides and 100‐nm critical feature size in the coupling region. In this work, a new method “damascene soft nanoimprinting lithography” is demonstrated that can create high‐fidelity waveguide by simply backfilling an imprinted cladding template with a high refractive index polymer core. This method can easily realize high Q‐factor polymer microring resonators (e.g., ≈5 × 105 around 770 nm wavelength) without the use of any expensive instruments and can be conducted in a normal lab environment. The high Q‐factors can be attributed to the residual layer‐free feature and controllable meniscus cross‐section profile of the filled polymer core. Furthermore, the new method is compatible with different polymers, yields low fabrication defects, enables new functionalities, and allows flexible substrate. These benefits can broaden the applicability of the fabricated microring resonator. A new Damascene soft Nanoimprinting Lithography method enables the fabrication of high Q‐factor of polymer microring resonators with low cost and without delicate tools. The residual layer‐free feature greatly reduces the radiation loss. The simple polymer filling strategy allows user to incorporate functional polymers into the microring resonator for different applications.