ABSTRACT In passive optical networks (PONs), due to the limited optical power budget, dynamic and non‐uniform power distribution among different links is often required to compensate for transmission losses. Therefore, reconfigurable beam splitters featuring low loss, non‐volatility, and fast tuning capability have become key building blocks for flexible optical distribution units (ODUs) as well as for programmable optical networks and photonic computing. Here, we experimentally demonstrate an electrically reconfigurable beam splitter based on the low‐loss phase‐change material Sb 2 Se 3 , enabling multi‐level and arbitrary splitting‐ratio control. By locally triggering phase transitions in the coupling region with integrated micro‐electrodes, we exploit the high refractive index contrast between different phases and negligible absorption in the near infrared wavelength of Sb 2 Se 3 to precisely tune the coupling strength with non‐volatile retention. 18‐level of power splitting states is achieved within a compact footprint of ∼14.5 µm in the experiments, with an insertion loss of ∼1 dB across 1500–1560 nm and near‐zero static power. Combining the advantages of compactness, broad bandwidth, low‐loss, non‐volatility, and multi‐level control experimentally, this device provides a universal building block for scalable, energy‐efficient reconfigurable photonic circuits, with great prospects in optical computing and intelligent communication systems.
Li et al. (Tue,) studied this question.