Laser diodes are usually the most expensive component in a solid-state laser system. The most frequent cause for failure in Oriental-laser laser modules is customer damage. The most frequently observed types of customer damage are (in order):
● Operating a laser module without coolant
● Using contaminated coolant
● Condensation on the diode (Operated chiller at less than dew point temperature)
To prevent damage to the laser diodes, Oriental-laser requires that the following guidelines be followed when designing the cooling water system for a laser module.
General Chiller Information
1. Oriental-laser equipment requires a chiller which can provide at least 60 psi (4.14 bar) water pressure. If your chiller can achieve the required minimum flow rate through the laser module with a lower water pressure (typically 30-50 psi [2.07-3.45 bar]), it is acceptable. The flow rate must be at or above the minimum flow rate listed in the table below.
2. Chillers used with Oriental-laser laser modules must have a heat capacity greater than the total power consumption of the unit(s) being cooled. Power consumed by the laser module is the power input into the laser module minus the optical power extracted from the module.
3. All Oriental-laser laser modules should be used with a flow interlock installed on the water output side of the module. If the chiller water is not flowing, or if the water drops below the minimum flow rate, the interlock should interrupt power to the diodes.
4. Oriental-laser laser modules should always begin life with the chiller set at the temperature recommended on the final test report (usually 20-30℃). As the laser module ages, it will be necessary to run the chiller at a cooler temperature to compensate for reduced efficiency and wavelength shift. Also, as the diodes degrade, more drive current maybe required to produce the required output power.
5. Oriental-laser does not endorse one chiller manufacturer over another. However, when Oriental-laser provides a module complete with chiller, we generally offer a Sun&Moon model with the laser. The following table lists the Sun&Moon chillers offered with Oriental-laser module types. The chiller is selected based on the expected end of life heat load for the laser module, with a slight allowance for heat load of a Q-switch capable of handling the module’s laser output.
1）. End of Life heat load (EOL) at 32A for GN series module. End Of Life heat load (EOL) at 100A or 200A for GQ/JQ water cooled module.
2）. The EOL value in the table refers to the final heat Load of the module with the highest average power among the modules of this grade.
