Accurate Measurements of the Wavelengths and Material Constants of 1.5 µm InGaAsP/InP Lasers

Abstract

The wavelengths of single longitudinal-mode 1.5 µn InGaAsP/InP lasers were measured at room temperature to an accuracy of 0.9 pm. An accurate wavementer was constructed for this purpose, and it exhibited an accuracy as high as 0.35 pm. The wavelength shifts of the lasers under unit changes in the injection current I and temperature T were derived from the results. By using the values of these wavelength shifts, the value of the temperature coefficient β of the refractive index in the cavity, and that of the thermal resistance R _T were accurately estimated. The results of these non-destructive measurements are as follows: (Laser No. 1) 1.03 × 10^-4 K^-1≦β≦1.07 × 10^-4 K^-1 and 79.8 K/W≦R _T ≦98.1 K/W (for 290 K≦T≦295 K and 86 mA≦I≦96 mA). (Laser No. 2) 0.81 × 10^-4 K^-1≦β≦0.83 ×10^-4 K^-1 and 133 K/W≦R _T ≦136 K/W (for 291 K≦T≦295 K and 70 mA≦I≦80 mA).