Patent ID: 9148247
Filing Date: 2015-09-29
Classification: H04B,H04J

Abstract:
1. An apparatus comprising: a first heterodyne detector configured to convert a received modulated optical signal into a first intermediate-frequency electrical signal by mixing the received modulated optical signal with an optical local-oscillator signal, the received modulated optical signal having (i) a first modulated optical carrier having encoded thereon a first data stream at a selected baud rate, said first modulated optical carrier having a first carrier frequency, and (ii) a second modulated optical carrier having encoded thereon a second data stream at the selected baud rate, said second modulated optical carrier having a second carrier frequency different from the first carrier frequency; a first band-pass filter configured to generate a first filtered electrical signal by passing a first spectral band of the first intermediate-frequency electrical signal, said first spectral band being approximately centered at a first intermediate frequency; a second band-pass filter configured to generate a second filtered electrical signal by passing a second spectral band of the first intermediate-frequency electrical signal, said second spectral band being approximately centered at a second intermediate frequency different from the first intermediate frequency such that an absolute value of a frequency difference between the first and second intermediate frequencies is smaller than the selected baud rate; and an electronic MIMO equalizer configured to generate a plurality of equalized electrical signals by applying equalization processing to a first digital baseband signal corresponding to the first filtered electrical signal and to a second digital baseband signal corresponding to the second filtered electrical signal; and wherein the apparatus is a signal processor configured to process the first and second filtered electrical signals to recover the first data stream and the second data stream based on the plurality of equalized electrical signals.