A wavelength division multiplexing (WDM) transceiver module comprising an optical port and an optical modulator is disclosed herein. The optical port includes a data transmit and receive optical fiber connector and a laser source-in optical fiber connector. The laser source-in optical fiber connector is configured to couple to a laser source external to the WDM transceiver module, and provide polarization alignment for a polarization-maintaining fiber. The optical modulator is configured to receive a laser output from the external laser source via the polarization-maintaining fiber and modulate the laser output based on analog electrical signals generated by a digital signal processor. The WDM transceiver module may not including an onboard laser source.