In order to guarantee the coupling effect of focused laser and water-jet fiber

accurate coupling alignment system was set up

special coupling alignment method was put forward

special coupling unit was designed. Before laser arriving at water-jet fiber

it passes through air

glasses and water

so based on calculating result

a special adjustment method was used to determine the distance between the focus lens and the nozzle hole. The max angle of incidence of laser was researched for full reflection. After fluid simulation

a coupling unit was designed. It makes the fluid field in the chamber symmetry and can form high quality water-jet fiber which diameter is 0.12mm. The attenuation of laser energy in water-jet fiber was investigated. Applying appropriate laser wavelength

pulse energy and filtered and deionized water

energy attenuation in fiber was reduced. Experimental results indicate that: 100mm long water-jet fiber could be formed; 0.12mm wide slot can be cut in 0.2mm thick Si wafer at the speed of 2mm/s

nearly no crack

no heat affected zone was formed. Applying this coupling technology

perfect water-jet guided laser micromachining can be achieved.