@conference{
author = "Vildoso, Paloma and Vicencio, Rodrigo A. and Petrović Jovana",
year = "2023",
abstract = "Conventional designs of multiport splitters rely on concatenation of directional couplers or multimode interference [1, 2]. However, the splitters show a considerable insertion loss and fast bandwidth drop with the number of ports. Inverse nanodesigns enable broadbandwidth semiconductor splitters, however, at high fabrication and design costs [3, 4]. In this work we present efficient and low-cost inverse design and experimental realization of multiport splitters with near-zero insertion loss, broad bandwidth and small footprint. Design is based on single-mode linearly coupled waveguide arrays which support periodic light propagation [5]. It allows for realisation of arbitrary splitting ratios by simple adjustment of waveguide separations. To demonstrate the technique, we designed equal 1×N power splitters and fabricated them in a borosilicate wafer by femtosecond laser writing method. The splitters show zero insertion loss within the experimental error, bandwidth of 20−60 nm and low imbalance < 0.5 dB. Their footprint scales exponentially with the waveguide separation, which can be reduced to the limit of mode confinement. Remarkably, the splitting ratio can be wavelength and array-length tuned. The proposed splitters offer new possibilities for path-entanglement generation, multipath interferometery on chip [6] and spatial mode multiplexing [7].",
publisher = "Belgrade : Institute of Physics",
journal = "16th Photonics Workshop (Conference) : book of abstracts; March 12-15, 2023; Kopaonik, 2023",
title = "Ultra-low-loss broadband multiport optical splitters",
pages = "19-19",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12919"
}