DASAN NETWORKS GPON Training Chapter 2. GPON Network - basics www.dasannetworks.eu

Table of contents www.dasannetworks.eu 1. Network elements 2. Used wavelengths 3. GPON – maximum reach 4. Optical characteristics 5. Theoretical power budget 6. Real power budget 7. Power budget for CATV Overlay (1550nm) 8. Using typical splitter except WDM Triplexer 9. Reach extenders 10. CWDM Overlay 11. How to connect www.dasannetworks.eu

1. Network elements www.dasannetworks.eu GPON network active devices/elements: GPON OLT (central device) GPON ONT (end customer device) GPON SFP C+ GPON passive elements: Optical splitters (e.g. symmetric 1:2,1:4,1:8, 1:16, 1:32,1:64) Maximum optical split on one GPON PORT is 1:128 – so to one GPON port You can connect up to 128 ONTs (depends on power budget – see more on next part) www.dasannetworks.eu

2. Used wavelengths www.dasannetworks.eu IPTV RF Overlay Downstream direction: 1490nm (+/- 10nm) Upstream direction: 1310nm (+/- 20nm) OPTIONAL: CATV Overlay (downstream): 1550nm (1550 -1560nm) RF Overlay Video Headend Optical Line Terminal IGMP GigE 1550 nm Soft Switch n GigE IP Router IPTV GigE Video Headend www.dasannetworks.eu

3. GPON – maximum reach www.dasannetworks.eu a b User Side Limitation: maximum distance between „Nearest ONT” and „Outermost ONT” is 20km. By DEFAULT – DASAN OLT is discovering ONTs on distance 0~20km (we can change this on OLT) User Side Outdoor Environment Central Office Outermost ONU ONU 1 a b a – b ≤ 20 km 20 km Maximum differential distance 60 km Logical Reach Maximum distance between OLT and outermost ONU supported by GTC OLT ONU 2 Splitter ONU N Nearest ONU 20 km Physical Reach Typical maximum distance considering infrastructure losses www.dasannetworks.eu

4. Optical characteristics Distance is defined by optical budget. Based on below optical characteristics: - ONT should receive optical signal (1490nm) from range: -28 ~ -8dBm FIBRAIN SFP GPON C+ ONT (1490/1310nm) VIDEO (1550nm) Tx Power: +3 ~ +7 dBm Receiver sensivity: -32 dBm Receiver overload: -12 dBm ONT X km Adapters and splice O NT Elements which decreases the optical signal: Optical splitters: 1:2 – 3.7dBm 1:4 – 7.1dBm 1:8 – 10.5dBm 1:16 – 13.7dBm 1:32 – 17dBm 1:64 – 20.5dBm 1:128 ~ 23.5dBm Adapters – 0.3dBm Splices – 0.02dBm Distance – 0,4dB for 1 km‏ (0.33dB for 1km 1310nm „Corning”) www.dasannetworks.eu

5. Theoretical power budget Theoretical optical budget calculation (based on datasheets) Fiber Adapter 1km 1:16 100m 1:4 5km 1:32 250m 12.25km x 0,4dB/1km = 4.9dBm Splitter 1:4 = 7.1 dBm Splitter 1:16 = 13.7 dBm 4 splices: 4x 0.1dBm = 0.4 dBm 7 fiber Adapters: 7x0,4dBm = 2.8 dBm Attenuation of violet link: 28.9dBm 12km 1:16 250m 1.100km x 0,4dB/1km = 0.44dBm Splitter 1:4 = 7.1 dBm Splitter 1:16 = 13.7 dBm 1 splice: 1x 0.05dBm = 0.05dBm 7 fiber adapters: 7x0,4dBm = 2.8dBm Attenuation of the red link: 24.09 5.250km x 0,4dB/1km = 2.1dBm Splitter 1:4 = 7.1 dBm Splitter 1:32 = 17 dBm 2 splices: 2x 0.05dBm = 0.1dBm 7 fiber adapters: 7x0,4dBm = 2.8dBm Attenuation of grink link : 29.1 dBm www.dasannetworks.eu

6. Real power budget (1) www.dasannetworks.eu Real (typical) optical budget calculation Fiber Adapter 1km 1:16 1:4 5km 1:32 250m 12.250km x 0.3dB/1km = 3.7dBm Splitter 1:4 = 6.5 dBm Splitter 1:16 = 13 dBm 4 splices : 4x 0.02dBm = 0.08dBm 7 fiber adapters: 7x0,3 dBm = 2.1dBm Attenuation : 25.38dBm 12km 1:16 250m 1.100km x 0,35dB/1km = 0.39dBm Splitter 1:4 = 6.5 dBm Splitter 1:16 = 13 dBm 1 splice: 1x 0.02dBm = 0.02dBm 7 adapters: 7x0,3dBm = 2.1 dBm Attenuation : 22.01 dBm 5.250km x 0,35 dB/1km = 1.84dBm Splitter 1:4 = 6.5 dBm Splitter 1:32 = 16.5 dBm 2 splices: 2x 0.02dBm = 0.04 dBm 7 adapters: 7x0,3dBm = 2.1 dBm Attenuation : 26.98 dBm ONT should receive optical signal (1490nm) from range: -28 ~ -8dBm www.dasannetworks.eu

6. Real power budget (2) – Received optical power Fiber Adapter 1km 1:16 1:4 RX Optical power for this ONT is: +4.5 – 22.01 = -17,51dB +4.5dB 5km 1:32 250m RX Optical power for this ONT is: +4.5 – 26.98 = -22,48 dB SFP GPON C+ is installed. C+ typical output power is +4.5dB 12km 1:16 250m Attenuation : 22.01 dB Attenuation : 26.98 dB Attenuation : 25.38dB RX Optical power for this ONT is: +4.5 – 25.38 = -20,88 dB ONT should receive optical signal (1490nm) from range: -28 ~ -8dB www.dasannetworks.eu

7. Power budget for CATV Overlay (1550nm) +20– 22.94=-2.94 RX 1550 should be – 2.94dB DASAN GPON OLT Spliter 1:32 100m 1km Spliter 1:2 Spliter 1:16 8km WDM - Triplexer 250m +20– 21.28=-1.28 RX 1550 should be – 1.28dB Example: BKTel Fx-AOT8200: CATV transmitter 1550nm + integrated EDFA TX 1550nm : +20dB 8.250km x 0,25dB/1km = 2.06dB Triplexer (WDM) = 0.8dB Splitter 1:2 = 3.5 dB Splitter 1:16 =13dB Splices: 6x 0.02dBm = 0.12 dB 6 Adapters: 6x0,3dBm = 1.8 dB Violet link attenuation for 1550nm: 21.28dB 1.100km x 0,25dB/1km = 0.275dB Triplexer (WDM) = 0.8dB Splitter 1:2 = 3.5 dB Splitter 1:32 = 16.5 dB Splices: 3x 0.02dBm = 0.06 dB 6 Adapters: 6x0,3dBm = 1.8 dB Violet link attenuation for 1550nm: 22.94dB ONT should receive optical signal (1550nm) from range: -8 ~ +2dB www.dasannetworks.eu

8. Using typical splitter except WDM Triplexer DASAN GPON OLT Spliter 2:2 1:16 100m 1km 1310nm 8km 1:16 1310nm 250m 1550nm Example: BKTel Fx-AOT8200: CATV transmitter 1550nm + integrated EDFA No WDM is needed as 2x2 splitter can inject 1550nm into fiber in this scenario. We can save on that 1dB. Disadvantages is that 1310nm is coming to EDFA but this does not make a trouble if proper EDFA is installed. 2xN spliter are also installed when GPON Protection is necessary. www.dasannetworks.eu

9. Reach extenders …… …… DASAN OLT 1310 nm 1490 nm 1310 nm 1490 nm GPON allow to install O/E/O converter to amplify signal from the OLT and from ONT to the OLT. Reach Extenders can increase the split ratio or optical budget but require electricity in the field. RE are working in L1 (ISO/OSI) only.   GPON combiners: Up to 8 GPON lines can be care by 1 fiber via CWDM technology and 2 active combiners. …… Ch 1 Ch 1 Ch 2 1450, 1470, 1490, 1510 1530, 1550, 1570, 1590 nm Ch 2 Ch 3 Ch 3 Ch 4 Ch 4 Ch A Ch B Ch 5 Ch 5 1450, 1470, 1490, 1510 1530, 1550, 1570, 1590 nm DASAN ONT Ch 6 Ch 6 Ch 7 Ch 7 Ch 8 Ch 8 …… DASAN OLT 1310 nm 1490 nm 1310 nm 1490 nm www.dasannetworks.eu

10. CWDM Overlay www.dasannetworks.eu In existing GPON network we can use also other wavelengths on the same optical link - wavelengths which are not affecting GPON/CATV Overlay communication. Thanks that we can connect some business clients. www.dasannetworks.eu

11. How to connect www.dasannetworks.eu Connectors: - GPON SFP: SC/PC (blue connector) - ONTs: SC/APC (green connector) What will happened when ONT will not receive correct optical signal: ONT may be NOT discovered on OLT ONT may be discovered on OLT, but will activate/deactivate all the time Problems with transmissions can be present (BER – Bit Error Rate) – will be visible on OLT syslog Please do not connect ONT directly to the GPON PORT (without proper attenuation added) because You can then damage ONT receiver. By default OLT is not discovering ONTs – You must enable it on OLT. GPON port diode will shine only when at least one ACTIVE ONT is discovered www.dasannetworks.eu

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