Accurate thermal impedance measurement for semiconductor lasers by the double modes of fiber grating lasers

The thermal impedance is an important parameter for a semiconductor laser, especially for a pump laser diode where a high current is needed to drive the laser to achieve the required performance. A precise measurement of thermal impedance is needed to characterize the thermal effect on the laser and to diagnose the thermal path on the laser packaging. Traditional measurements for the thermal impedance involve pulsing or modulating the lasers. Here, for the first time we used a complete optical method without electrical pulsation or modulation. The double mode spectra of fiber grating lasers were used to measure the thermal impedance of a semiconductor laser with accuracy not obtainable by other methods