Blu-ray - The Next Generation Media Format Blu-ray - The Next Generation Media Format Blu-ray, a next-generation optical disc format, also known as Blu-ray Disc (BD). Blu-ray has a storage capacity of 25GB on a single-layer disc and 50GB on a dual-layer disc. While DVD, DVD-R, DVD+R rely on a red laser to read & write data, Blu ray disc uses a blue-violet laser instead. The benefit of using a blue-violet laser (405nm) is that it has a shorter wavelength than a red laser (650nm), which makes it possible to focus the laser spot with even greater precision. This allows data to be packed more tightly and stored in less space, so BR-D can fit more data even though it's the same size as a CD/DVD.