Coherent PolMux Reception Using a Low-Cost Heterodyne Receiver

Nowadays, 25 Gbps to 100 Gbps single-wavelength Passive Optical Network (PON) links are expected to become the next generation optical access networks and coherent PONs represent an interesting option to overcome the poor sensitivities of traditional direct detection (DD) at these high data rates. However, coherent schemes need complex Digital Signal processing (DSP) and are polarization sensitive. Different solutions have been proposed to make coherent receivers insensitive to polarization but, in this work, we propose a different approach using a Glance heterodyne polarization insensitive receiver [1], [2] as a PolMux receiver to double the bit rate. Although digital recovery of the PolMux data has been widely studied for intradyne schemes, it has been completely redesigned and implemented for our heterodyne scheme including a four independent complex coefficients rotation matrix, instead of the classical two coefficients commonly used in intradyne schemes, and an autonomous and automatic training of the matrix.