Waveguide devices have been produced comprising germania-doped silica
cores and silica claddings on silica substrates, using microwave plasm
a assisted chemical vapor deposition and reactive-ion etching. This al
l-silica structure offers the maximum compatibility between fibers and
waveguides in terms of both optical and physical properties. The all-
silica philosophy is extended to the use of laser-cut silica V grooves
in the construction of input/output fiber arrays. An important featur
e of this approach is that it enables fiber/waveguide interfacing by C
O2 laser welding of the respective silica blocks without the introduct
ion of any significant additional loss. Both the waveguide fabrication
and laser-welding processes are well suited to large-scale production
of low-cost components.