A lithium niobate digital optical waveguide switch for optical circuit protection

Electro-optic waveguide switches are capable of switching at very high speeds and by careful design broadband optical switches which are insensitive to polarisation can be produced that are compatible with existing fibre optic networks. The design and fabrication of a polarisation independent lithium niobate digital optical switch and its performance at both 1.3 μm and 1.5 μm is reported. The performance of this device when operated as a protection switch in a 140 Mbit/s wavelength multiplexed optical fibre system is described and the implications for optical network design if switches of this type were to be employed is considered