Multi kW class blue laser system

An optical apparatus configured to produce a multi-kW laser radiation with blue emission in a range of 400 nm to 495 nm, the optical apparatus comprising:

• a. a plurality of fiber-coupled modules, where each of the plurality of modules comprises a plurality of submodules;
• i. wherein the submodules comprise a lensed blue semiconductor gain chip from a GaN material system, with a coating on a front facet with lower reflectivity optimized for locking;
• ii. wherein the gain chip is mounted on thermally conductive sub-mount, with the lower reflectivity facet facing outward and with a fast axis-collimating lens attached in front of the gain chip;
• iii. wherein the gain chip is mounted on a staircase heatsink in a cavity to optimally align a fast axis beamlet;
• iv. wherein the gain chip has its slow axis collimated by a slow axis collimating lens and has its radiation being redirected by a turning mirror to an output coupler;
• and,
• v. wherein each of the submodules is aligned through a dichroic filter and the output coupler provides feedback to the gain chip and the dichroic filter determines an operating wavelength of each of the submodules;
• b. wherein the plurality of submodules in the plurality of fiber-coupled modules is configured, whereby;
• i. two groups of two submodules are combined through wavelength multiplexing with a bandwidth of <10 nm to define two wavelength multiplexed submodule groups;
• and,
• ii. the two wavelength multiplexed submodule groups are combined via polarization beam combining into an output fiber;
• c. the output fibers of the plurality of fiber-coupled modules are bundled and combined into a single output fiber, thereby defining a KW-level blue laser system.