New Designs for the Fun-COMP Tensor Core Fun-COMP team have continued to improve the design and operation of their photonic tensor core (PTC) processor, that we reported in Nature last year (see In work recently reported in the Nanophotonics journal, Fun-COMP researchers showcased an optimized layout of their photonic tensor core – one that is designed to perform real valued matrix vector multiplications and operates at telecommunication wavelengths. We deploy the well-studied phase-change material Ge2Sb2Te5 (GST) as an optical attenuator to perform single positive valued multiplications. In order to generalize the multiplication to arbitrary real factors, we develop a novel symmetric multiplication unit which directly includes a reference-computation branch. The variable GST attenuator enables a modulation depth of 5 dB over a wavelength range of 100 nm with a wavelength dependency below 0.8 dB. The passive photonic circuit itself ensures equal coupling to the main-computation and reference-computation branch over the complete wavelength range. For the first time, we integrate wavelength multiplexers (MUX) together with a photonic crossbar array on-chip, paving the way towards fully integrated systems. For more details see the paper at