Practical Realisation Of An Optical Fibre Transmission System Using Heterodyne Detection

An experimental optical system with heterodyne detection has been designed and constructed. Particular attention has been paid to laser stabilisation and the requirement for optical isolation. The system also includes a microprocessor based controller for automatic signal and polarisation acquisition and tracking. A receiver sensitivity of -41 dBm has been achieved with standard DFB lasers. All the optical components used in the system are fitted with monomode fibre pigtails. This allows the system to be housed in a standard telecommunications equipment shelf of the type used in practical installations.