Pressure tuned laser diode as a light source for characterization of optical transmission lines

Room-temperature emission of 1310 nm InGaAsP-InP laser diode has been studied as a function of hydrostatic pressure in an optical clamp cell up to 20 kbar. The diode was a commercial single-mode device by Siemens. The emission line shifted towards the shorter wavelengths similar to the bandgap of the constituent materials. The tuning range was over 200 nm. Here we consider the possibility of applying the high pressure cell with commercial laser diode inside as a pressure-tuned light source because of its narrow lines, wide tuning range and easy to implement portable equipment. It could be useful for measuring absorption and dispersion in optical transmission lines. Application of different types of electronically tunable lasers in the cell could further extend the tuning range and provide fine tuning and continuous tuning.