Experimental and Numerical Evaluation of High Power Fabry-Perot Semiconductor Lasers with Considerations of Thermal Effects

We demonstrated a high power Fabry-Perot semiconductor laser with a close-to-100mW optical output at 1550nm band. A thermal model was numerically applied to extract the thermal impedance of this device.

1. Introduction

In recent years, the developments of several key technologies, such as low-Earth-orbit (LEO) satellite communications and co-packaged optics, have brought up the demand for high power semiconductor lasers. Because of the need for high data transmission, the number of data channels is increasing and the corresponding light source has to increase its output as a result. As high as 200mW per single laser chip was demonstrated [1]. In contrast to the traditional telecommunication components, which only takes 10mW in average [2], the power requirement is up to one order higher. Other applications, such as LiDAR and LEO satellites, also require a much higher laser output simple due to the huge loss induced by free-space signal transmission [3]. At the power level of 100 mW per chip, the thermal dissipation problem is going to be an serious issue to solve. Without a good understanding of this phenomenon, the subsequent package or device optimization will be futile. In this study, we will provide our first observation in both experimental and numerical aspects to evaluate high power Fabry-Perot lasers. It is important to know that the thermal effect in these devices is critical and needs to be incorporated properly. Therefore, we developed a numerical procedure to extract the thermal impedance of the laser when its optical power was measured. Fig. 1.

The 1250 μm laser bar under microscope.

Fig. 2.

The measured L-I profiles and slope efficiencies of a 1250-μm laser and a 300-μm FP one.

Fig. 3.

The measured spectra of a 750-μm device under 30, 50, 70, and 90 mA of injection currents.