Experimental demonstration of replicated multimode interferometer power splitter in Zr-doped sol-gel

A single-mode waveguide and a 1 x 3 multimode interference (MMI) power splitter are fabricated in hybrid zirconium (Zr)-doped sol-gel material by a microreplication technology with a polydimethylsiloxane (PDMS) replica. The power splitter, as optimized using a finite-difference beam-propagation method (FD-BPM) simulation with self-imaging effects, represents one of the first experimental demonstrations of a high-tolerance manufactured device using replication methods. The fabrication of the microreplicated power splitter demonstrates high-quality optical and geometrical properties. The local uniformity in thickness of the multimode waveguide is less than 1.0%, and the average surface roughness is about 5.35 nm. The measured splitting loss is less than 0.6 dB for both transverse polarizations at the 1550-nm wavelength. Experimental achievements indicate that the soft lithography technology allows for the performance of applications in integrated optical devices in Zr-doped sol-gel materials with high standards.