https://www.nature.com/articles/s41586-020-03070-1The 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 https://www.nature.com/articles/s41586-020-03070-1). 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 https://www.degruyter.com/document/doi/10.1515/nanoph-2021-0752/html