Research is underway to develop the technology required for 200 Gbps lanes. At OFC 2021, Keysight demonstrates accurate waveform tests for next-generation transmitters using an N1000A DCA-X, N1030A optical reference receiver, and a UXR-Series oscilloscope with an N7005A external O/E converter. This test system will be used to characterize signals generated by a 212 Gbps E/O driven by a M8199A AWG.