Rec. ITU-T G.984.2 (08/2019) - Gigabit-capable passive optical networks (GPON): Physical media dependent (PMD) layer specification Summary History FOREWORD Table of Contents 1 Scope 2 References 3 Definitions 3.1 Terms defined elsewhere 3.2 Terms defined in this Recommendation 4 Abbreviations and acronyms 5 Architecture of the optical access network 6 Services 7 User network interface and service node interface 8 Optical network requirements 8.1 Layered structure of optical network 8.2 Physical medium dependent layer requirements for the GPON 8.2.1 Digital signal nominal bit rate 8.2.2 Physical media and transmission method 8.2.2.1 Transmission medium 8.2.2.2 Transmission direction 8.2.2.3 Transmission methodology 8.2.3 Bit rate 8.2.3.1 Downstream 8.2.3.2 Upstream 8.2.4 Line code 8.2.5 Operating wavelength 8.2.5.1 Downstream direction 8.2.5.2 Upstream direction 8.2.6 Transmitter at Old and Oru 8.2.6.1 Source type 8.2.6.2 Spectral characteristics 8.2.6.3 Mean launched power 8.2.6.3.1 Launched optical power without input to the transmitter 8.2.6.4 Minimum extinction ratio 8.2.6.5 Maximum reflectance of equipment, measured at transmitter wavelength 8.2.6.6 Mask of transmitter eye diagram 8.2.6.6.1 OLT transmitter 8.2.6.6.2 ONU transmitter 8.2.6.7 Tolerance to the reflected optical power 8.2.7 Optical path between Old/Oru and Ord/Olu 8.2.7.1 Attenuation range 8.2.7.2 Minimum optical return loss of the cable plant at point R/S, including any connectors 8.2.7.3 Maximum discrete reflectance between points S and R 8.2.7.4 Dispersion 8.2.8 Receiver at Ord and Olu 8.2.8.1 Minimum sensitivity 8.2.8.2 Minimum overload 8.2.8.3 Maximum optical path penalty 8.2.8.4 Maximum logical reach 8.2.8.5 Maximum differential logical reach 8.2.8.6 Maximum reflectance of receiver equipment, measured at receiver wavelength 8.2.8.7 Differential optical path loss 8.2.8.8 Clock extraction capability 8.2.8.9 Jitter performance 8.2.8.9.1 Jitter transfer 8.2.8.9.2 Jitter tolerance 8.2.8.9.3 Jitter generation 8.2.8.10 Consecutive identical digit immunity 8.2.8.11 Tolerance to reflected power 8.2.8.12 Transmission quality and error performance 8.3 Interaction between GPON PMD layer and TC layer 8.3.1 Forward error correction 8.3.2 Power levelling mechanism at ONU transmitter 8.3.3 Upstream physical layer overhead Annex A Industry best practice for 2.488 Gbit/s downstream, 1.244 Gbit/s upstream GPON class B+ A.1 Introduction A.2 System applications A.3 Optical specifications A.4 Link budget Annex B Description of physical layer measurements to support optical layer supervision B.1 Introduction B.2 Transceiver parameters monitoring B.3 Measurement table for transceiver parameters B.4 OLS physical layer performance measurements requirements Appendix I Allocation of the physical layer overhead time Appendix II Description and examples of power levelling mechanism II.1 Introduction II.2 ONU levels II.3 Thresholds at OLT II.3.1 Case 1: Comparison to two thresholds (TL, TH) II.3.2 Case 2: Comparison to one threshold (TL) II.4 Power detection Appendix III Appendix IV Appendix V Industry best practice for single-sided extended 2.488 Gbit/s downstream, 1.244 Gbit/s upstream GPON (class C+ and class D) V.1 Introduction Bibliography