Spectrally-sliced coherent receivers for THz bandwidth optical communications

The bandwidth of an optical coherent receiver is limited by the speed of its electronic components, such as the photodetectors and the analog-to-digital converters. These electronic limitations prevent coherent receiver bandwidths from scaling beyond several tens of GHz. To scale bandwidths up towards a terahertz, we measure a waveform in many narrowband and slightly overlapping spectral slices using efficient optical wavelength demultiplexing, an optical frequency comb, and an array of coherent receivers. I will overview the spectral-slice approach and show measurements of telecommunications waveforms with bandwidths over 200 GHz.