Fibre-based communication

An apparatus comprising:

• two optical transmitters, each optical transmitter comprising a dual-rail encoder configured to obtain light from a light source and to output dual-rail encoded light and a polarization rotator combiner configured to convert the dual-rail encoded light into polarization encoded light;
• at least one processing core configured to obtain compensation adjustment information concerning two fibres and to control the dual-rail encoders based at least in part on the compensation adjustment information, wherein
• the light sources of the optical transmitters comprise laser sources operating at the same frequency, such that the laser sources are injection locked to the same frequency.

A method, comprising:

• in each of two optical transmitters, obtaining light from a light source, encoding dual-rail encoded light in a dual-rail encoder and converting the dual-rail encoded light into polarization encoded light;
• obtaining compensation adjustment information concerning two fibres and controlling the dual-rail encoders based at least in part on the compensation adjustment information, wherein
• the light sources comprise laser sources operating at the same frequency, such that the laser sources are injection locked to the same frequency.