Trace gas detection with short-external-cavity InGaAsP diode laser transmitter modules operating at 1.58 microm.

Detection of CO(2) and CO at 1.58 microm (6322 cm(-1)) using an InGaAsP diode laser and mode control is described.Mode control is a technique whereby a short cavity, external to the laser, is used to force the laser to operate in a single mode. By monitoring the voltage across the terminals of the laser and using electronic feedback it is possible to optimize continually the external cavity so that the laser operates reliably in the mode of …