25GBaud PAM-4 error free transmission over both single mode fiber and multimode fiber in a QSFP form factor based on silicon photonics. - Marco Mazzini; Matt Traverso; Mark Webster; Cristiana Muzio; S. Anderson; P. Sun; D. Siadat; D. Conti; Alberto Cervasio; S. Pfnuer; J. Stayt; M. Nyland; et al. (OFC, 2015)