NOVELTY - The laser (38) has a ytterbium (Yb) doped fiber amplifier for receiving and amplifying a single frequency single mode (SFSM) polarized pump light at fundamental wavelength. A non-linear optical frequency converter converts the amplified SFSM polarized pump light at the fundamental wavelength in a single-pass second-harmonic generation (SHG) scheme to a SM output green light at a signal wavelength. A SM fiber laser unit operates with a wall plug efficiency between 15-35% in a 510-540 nm wavelength range and in a power range between about 50 W and kW-levels.    USE - High power SM fiber laser i.e. semiconductor diode pumped solid state green laser (DPDS) for being operated in a green spectral range in a continuous- wave (CW) mode or quasi-continuous-wave (QWC) mode of a 1064 nm laser system (claimed) i.e. neodymium-doped yttrium aluminum garnet Neodymium-doped yttrium orthovanadate (Nd: YAG and Nd: YV04) laser system for green laser applications such as copper welding-wafer annealing, low temperature poly-silicon (LTPS) display annealing and power electric vehicle powering solar cell manufacturing applications. Can also be used for an entertainment industry for a laser-shows and laser projectors.    ADVANTAGE - The laser is generated at shorter wavelength so as to maintain low divergence and small-sized focal spot, and utilizes relatively low and high-reflective copper, gold and silver metals at the shorter wavelengths so as to allow high percent of power to be coupled into a target. The laser is powerful and efficient to use and compact in structure. The laser improves light outputting efficiency, and is connected with a Raman converter that receives the output Green light at a signal wavelength, and is configured to output Raman-shifted green light at a first or higher stokes wavelengths so as to eliminate visual appearance of speckles in the green output light incident on a screen.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a laser system.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a high-power CW green laser provided with a line width-broadening system.    High power SM fiber laser (38)    Line width- broadening system (40)    SM polarization-maintaining multi-stage fiber amplifier (42)    Booster amplifier (44)    Focusing optic (46)