  The polarisation of light is a powerful and widely used degree of freedom to
encode information, both in classical and quantum applications. In particular,
quantum information technologies based on photons are being revolutionised by
the use of integrated photonic circuits. It is therefore very important to be
able to manipulate the polarisation of photons in such circuits. We
experimentally demonstrate the fabrication by femtosecond laser micromachining
of components such as polarisation insensitive or polarising directional
couplers, operating at 1550 nm wavelength, where the two opposite behaviours
are achieved just by controlling the geometric layout of the photonic circuits,
being the waveguides fabricated with the same irradiation recipe. We expect to
employ this approach in complex integrated photonic devices, capable of a full
control of the photons polarisation for quantum cryptography, quantum
computation and quantum teleportation experiments.
