Laser written waveguides to the sample edge

Abstract: A method is presented for fabrication of femtosecond laser written waveguides in glass to remove the need for polishing of substrates after processing. It is shown that by amplitude masking the fabrication laser beam near the sample edge and increasing the pulse energy it is possible to write waveguides that are not affected by edge aberrations and display mode profiles well matched to single mode fibre. Results are presented for different depths in fused silica and borosilicate glass substrates. The transmission from fibre to photonic circuit is significantly improved for situations where it is not possible to polish glass substrates after laser writing, creating new opportunities in photonic packaging.