Whether supernovae (SNe) are a significant source of dust has been a long-standing debate. I will review  infrared observations of the young supernova remnants (YSNRs) -- Cas A, SNR 1E102.2-7219 (E0102), N132D, and the Crab Nebula using Spitzer and Herschel data. These SNRs reveal evidence of dust formation and presence of cold dust, and show that SNe are important sites of dust formation and produce dust on short time-scales. I will present detection of cold dust from another Crab-like SNR, G54.1+0.3, using Spitzer and Herschel data, and a revisit of the dust mass in Cas A with the first spatially resolved analysis of Cas A based on Spitzer and Herschel infrared and submillimetre data. I will discuss  dust features and composition, total dust masses, and a significance of supernovae dust in the early Universe and galaxies. I will also present the introduction of the  LSST project, the LSST observing strategy and its optimization for SN cosmology and SN science, and ideas of the LSST follow-up optical/infrared spectros.