This paper presents a 200Gbps PON uplink burst coherent reception system that utilizes polarization-independent 4PAM optical intensity modulation-polarization diversity. To accommodate the burst changes in the PON uplink, we propose an adaptive channel equalization algorithm based on training sequences. This algorithm is characterized by low overhead, allowing for fast convergence. Simulation results demonstrate that adaptive compensation of PMD is feasible with a mere 18.5ns of preamble overhead. Additionally, by including only one SOA as a pre-amplifier in the OLT, a system power budget exceeding 35dB can be achieved.