A method of manufacturing a waveguide in a glass plate is disclosed. The glass plate is scanned with a laser beam directed orthogonally to the glass plate to form a trench according to a pattern of the waveguide to be formed. The scanning is performed by pulses of the laser beam having a duration between 2 and 500 femtoseconds. The glass plate with the trench is treated with hydrofluoric acid. After treating the glass plate, the trench is filled with a material having an index different from that of glass, and, after filling the trench, a cladding layer is deposited.