Optical communication system

A downhole optical communications system, configured to be provided at a downhole location in use, for communicating between the downhole location and an uphole location, wherein the downhole optical communications system comprises:

• a downhole optical transmitter configured to emit an uplink optical signal for transmission over an optical transmission channel between the downhole optical transmitter and the uphole location;
• and
• an electrical switch;
• wherein
• the downhole optical transmitter is configured to produce a response to an downlink optical signal received from the optical transmission channel;
• the downhole optical communications system is configured to determine data represented by the received downlink optical signal from the response produced by the downhole optical transmitter;
• the downhole optical communications system is configured to be switchable from a dormant or unpowered state to an active or powered state upon receiving the downlink optical signal;
• the response produced by the downhole optical transmitter comprising generation of an electrical potential that is provided to the electrical switch to cause the electrical switch to switch states to thereby connect a power supply;
• and
• the power supply continued to latch the electrical switch into a persistent operational state.