Roadmap to Simplified Coherent Heterodyne Receivers for 100 Gb/s PONs

Traditional Intensity Modulation/Direct Detection (IM/DD) based Passive Optical Networks (PONs) face limitations, including poor sensitivity and chromatic dispersion issues, as well as frequency fading for high data bit rates, which make coherent receivers a promising alternative for PONs. Coherent receivers improve optical power budgets, enhance spectral efficiency, and mitigate chromatic dispersion issues. However, their deployment in access networks remains challenging due to the cost associated with additional components such as local oscillator (LO) lasers, high frequency electronics and polarization management devices.In this paper, we discuss these constraints and present our approaches to achieve low-cost coherent heterodyne polarization independent receivers for 50/100 Gb/s PONs. Starting with a simplified polarization-insensitive heterodyne coherent receiver for 50 Gb/s, we analyze the roadmap to a DSP-enabled PolMux heterodyne coherent receiver for up to 100 Gb/s. All these approaches rely on low-cost 10G optoelectronics and can be easily integrated into miniatured Photonic Integrated Circuits (PICs).