METHOD OF MAKING OPTICAL FIBRE PREFORMS AND OPTICAL FIBRE PREFORM

摘要

A method of making a high birefringence optical fibre comprises depositing a layer of glass of a first expansivity on the inside of a tube of a second expansivity, differentially etching the layer to form two diametrically opposed strips, depositing a third layer of glass over the strips and shrinking the preform to form a glass fibre with a conventional sheath (24) and core (26) clad with an asymmetrical layer of doped (22) and undoped (20) glass.