Supervisory options for fibre optical amplifier systems

Optical transmission systems using optical amplifiers as repeaters will require remote monitoring and control as part of the network management of the system. Methods used on regenerative systems, which utilise access to the data signal at each repeater, are inappropriate for optically amplified systems. With optical amplifiers, two categories of supervisory have been identified; passive and active. For long or medium haul systems, either submarine or landline, the passive approach offers simplicity but no detailed information on the amplifier status. On the other hand, an active supervisory offers the possibility of a very detailed profile of the amplifier status, but at the expense of complexity. In general, the optimum supervisory system depends on the details of the application, the capabilities of the technology and the reliability requirements. However, in short to medium haul applications passive systems may be optimum because of their simplicity. The authors introduce the options available for optical amplifier supervisory, including system design, and give details of one option that has been successfully demonstrated over medium and long haul amplifier systems. This option is the integrated optical supervisory system using gain modulation.