OPTICAL SIGNAL TRANSMITTING DEVICE, OPTICAL SIGNAL RECEIVING DEVICE AND OPTICAL SIGNAL TRANSMISSION SYSTEM

Embodiments of this application disclose an optical signal transmitting device, an optical signal receiving device, and an optical signal transmission system, to implement, via a mode converter, mode division multiplexing and wavelength division multiplexing of a multi-path transmitted optical signal. This expands a capacity of the optical signal transmission system. In the optical signal transmitting device, the mode converter performs phase conversion on the multi-path transmitted initial optical signal to obtain a single-path transmitted first target optical signal, where the initial optical signal includes a first optical signal and a second optical signal whose wavelengths are a first wavelength, and a third optical signal whose wavelength is a second wavelength, the first target optical signal includes the third optical signal, the first optical signal transmitted in a first mode, and the second optical signal transmitted in a second mode, and the first wavelength is different from the second wavelength.