Fiber optic cable power in repeatered systems

A system, for subsea optical communications, comprising:

• a station, to launch an optical signal over a signal path;
• a plurality of optical repeaters, to amplify the optical signal along the signal path;
• a cable to conduct the optical signal along the signal path, the cable comprising an electrical conductor to conduct power to the plurality of optical repeaters, wherein a given optical repeater of the plurality of optical repeaters comprises:
• an erbium doped fiber;
• and
• an optical pump unit, comprising:
• a line voltage transistor, coupled between an input side and an output side of the optical pump unit;
• a DC-to-DC converter, having an input side coupled to the line voltage transistor;
• an optical pump assembly, coupled to an output side of the DC-to-DC converter;
• a current control assembly, coupled to the optical pump assembly;
• a throttle back control assembly, having an output coupled to the current control assembly;
• and
• a current and voltage sensor, to monitor a line current and repeater voltage drop in the optical repeater, and being coupled to an input of the throttle back control assembly, wherein the throttle back control assembly is configured to send a signal to the current control assembly to reduce a power at the optical pump assembly when a decrease in line current or repeater voltage drop takes place.