Polarisation stability of optical solitons

Optical solitons are a topic of increasing importance with major applications in trans-oceanic communications (temporal solitons) and all-optical reconfigurable interconnects (spatial solitons). Initial investigations considered only single component solitons but research has advanced to considering the practicalities and problems of multi-component solitons. There are several possible implementations of this, including multiple wavelengths, but the most straightforward is based on the two orthogonal polarisation components. If the medium has a low birefringence then four-wave-mixing leads to an exchange of energy between the two components. We consider two examples of such systems employing a Kerr nonlinearity (1) temporal solitons in birefringent optical fibre and (2) spatial solitons in semiconductor slab waveguides.