Abstract: An optical fibre comprising at least one single core structure arranged in a manner such that, in use, it supports both single-mode and multi-mode propagation for data transfer.

Abstract: An optical modulation system for independently modulating multiple wavelengths and transmitting them along a single output waveguide, the system comprising: a series of optical modulator elements each having at least one modulator waveguide input for inputting a single wavelength and modulation means for modulating the input single wavelength to produce a modulated wavelength output; an array of optical laser emitters, each emitting at a separate wavelength, the array having a series of wavelength outputs, one each of which is interconnected to the waveguide modulator input of the series of optical modulator elements; and an optical multiplexer taking a series of a modulated wavelength outputs having differing wavelengths and for multiplexing the multiple wavelengths together for output onto the single output waveguide.