Using polarization modulation techniques to simultaneously transmit two different data streams (formatted according to two different protocols) over a single optical wavelength. A first data stream that is encapsulated for transport using a first transport protocol, and a second data stream that is encapsulated for transport using a second transport protocol are received. The first data stream is modulated on a wavelength with a first polarization mode of a polarization division modulation scheme to produce a first modulated data stream and the second data stream is modulated on the wavelength with a second polarization mode of the polarization division multiplex transmission scheme to produce a second modulated data stream having the second polarization mode. The second polarization mode is orthogonal to the first polarization mode. The first and second data streams are combined onto a single wavelength for transmission over a single optical fiber using a polarization beam combiner.