High power laser packaging challenges and standardization

The initial study of the electromagnetic acoustic resonance effect in high power semiconductor laser packages is reported here, along with the first detailed investigation on the thermal impact of the pins on some standard high power laser packages. This paper reviews the challenges of packaging high power lasers and fiber optic modules, including electrical, thermal, mechanical, and different material requirements. Computer modeling and experimental studies have been done on some of the packages currently available on the market. The studies have found that high power lasers operated at quasi-continuous wave (QCW) input current above a few amps can emit acoustic noises generated by electromagnetic forces, which may excite the resonance frequencies of the laser package. We call this phenomenon electromagnetic acoustic resonance (EMAR). An input QCW frequency was swept from 100 Hz to 20,000 Hz, and audible noises were detected from several standard high power laser packages, such as HHL (high heat load) and TO-3. Additional findings are reported in this paper including the fact that standard high power laser packages, such as Butterfly fiber optic package and HHL package, can generate heat energy when high current is passed through their pins. This unwanted heat energy can in turn feed back to the laser, which would impact the laser performance. The temperature on the pin of a Butterfly package, for example, can rise to 80°C when a 3 amp current passes through it. This paper provides both experimental and theoretical studies on these issues. Based on the study results, some recommendations on changes are proposed at the end of the paper in order to improve the performance of laser packaging. These recommendations are also intend to promote standardization of the packages of high power laser in the future, which could reduce the cost of high power laser packaging.