Embodiments of the present invention disclose an optical signal transmission method, apparatus, and system. The apparatus includes a short wavelength division multiplexer, a signal processor, a first linear driver, a second linear driver, a first transmitter, and a second transmitter. The signal processor is configured to perform bit rate allocation and code pattern modulation on a received binary signal, to obtain a first electrical signal to be sent to the first linear driver and a second electrical signal to be sent to the second linear driver. It can be learnt that, by implementing the embodiments of the present invention, a quantity of wavelengths transmitted in a multimode optical fiber can be reduced by performing bit rate allocation on a binary signal, thereby reducing interference between channels in the optical fiber for optical signal transmission.