 Additional experimental developments include a prism-pair pulse compressor and a six-prism pulse compressor for semiconductor lasers.The multiple-prism dispersion theory, for pulse compression, was introduced in 1982 by Duarte and Piper, extended to second derivatives in 1987, and further extended to higher order phase derivatives in 2009.An additional compressor, using a large prism with lateral reflectors to enable a multi-pass arrangement at the prism, was introduced in 2006.