Early lasers primarily utiized tungsten copper C-Mount structures,which later transitioned to tungsten copper bars. Initially,W85Cu15 was predominant, but currently,W90Cu10 is the main composition.It is suggested to experiment with W93Cu7 in the future. Tungsten copper bars serve as conductors,heat sinks,and chip carriers.Galium nitride chips are sandwiched
between them and soldered with gold-tin solder.several laser modules utiize tungsten copper bars,varying from a few to dozens of pieces.
In the early days, about 10 years ago, the power of laser chips was not high, and the requirements for tungsten copper bars were not stringent. Now,fhe power is increasing,and the demands tor tungsten copper bar size accuracy, thermal expansion coefficient matching,thermal conductivity,and coating bonding are becoming more rigorous. This is mainly evident in the need for the thermal expansion coefficient to be close to galium arsenide (5.9×10-6/k),maximizing thermal conductivity,experimenting with diamond composite materials,and enforcing strict control over key surfaces, finishes,edges (R10 microns),and coatings (nickel,gold,platinum, and locally prefabricated gold and tin).A decade ago,we were the sole manufacturerof tungsten copper bars in China, but now many manufacturers are entering this field.