1. Broadband Optical Networks
Delivered by
Dr. Erna Sri Sugesti
4 Maret 2015

2. Agenda
Fiber Optics System- Overview
PON Technologies and Developments

3. Fiber optics - overview

4. Total Internal Reflection in Step-Index Multimode Fiber1
© = sin¯ (n2/n1)
t = Propagation Time
t Vacuum: n=1, t=3.336ns/m
V =c/n
t Water : n=1.33, t=4.446ns/m
t = L·n/c

5. Types of Optical Fiber Popular Fiber Sizes Single-mode Fiber
Multimode Graded-Index Fiber
Single-mode Fiber

6. Click to edit Master text styles
Optical Loss versus Wavelength
Click to edit Master text styles
Second level
Third level
Fourth level

7. Total Dispersion Sources of Dispersion Multimode Dispersion
Chromatic Dispersion
Material Dispersion

8. Dispersion limits bandwidth in optical fiber
Multimode Dispersion 1 1 1 1 1 1
Dispersion limits bandwidth in optical fiber

9. Graded-index Dispersion1 1 1 1

10. Single-Mode Dispersion1 1 1 1 1
In SM the limit bandwidth is caused by chromatic dispersion.

11. Tc = Dmat *  * L How to calculate bandwidth?
System Design Consideration
How to calculate bandwidth?
For a 1.25 Gb/s we need a BW of 0.7 BitRate = 1.143ns
Tc = Dmat *  * L
For Laser 1550nm Fabry Perot
Tc = (20ps/nm * km) * 5nm * 15km = 1.5ns
For Laser 1550nm DFB
Tc = (20ps/nm * km) * 0.2nm * 60km = 0.24ns

12. Material Dispersion (Dmat)

13. Spectral Characteristics
LASER/laser diode: Light Amplification by Stimulated Emission of Radiation. Done of the wide range of devices that generates light by that principle. Laser light is directional, covers a narrow range of wavelengths, and is more coherent than ordinary light. Semiconductor diode lasers are the standard light sources in fiber optic systems. Lasers emit light by stimulated emission.

14. Laser Optical Power Output vs. Forward Current

15. Light Detectors PIN DIODES (PD)
Operation simular to LEDs, but in reverse, photon are converted to electrons
Simple, relatively low- cost
Limited in sensitivity and operating range
Used for lower- speed or short distance applications
AVALANCHE PHOTODIODES (APD)
- Use more complex design and higher operating voltage than PIN diodes
to produce amplification effect
Significantly more sensitive than PIN diodes
More complex design increases cost
Used for long-haul/higher bit rate systems

16. Wavelength-Division Multiplexing

17. WDM Duplexing

18. Passive optical networks (PON) technology and Developments

19. Basic Configuration of PON
OLT = Optical Line Termination
ONU = Optical Network Unit
BMCDR = Burst Mode Clock Data Recovery

20. Typical PON Configuration and Optical Packets

21. Access network bottleneck
hard for end users to get high datarates because of the access bottleneck
local area networks
use copper cable
get high datarates over short distances
core networks
use fiber optics
get high datarate over long distances
small number of active network elements
access networks (first/last mile)
long distances
so fiber would be the best choice
many network elements and large number of endpoints
if fiber is used then need multiple optical transceivers
so copper is the best choice
this severely limits the datarates
core
access
LAN

22. Fiber To The Curb core Hybrid Fiber Coax and VDSL
switch/transceiver/miniDSLAM located at curb or in basement
need only 2 optical transceivers
but not pure optical solution
lower BW from transceiver to end users
need complex converter in constrained environment
core
N end users
feeder fiber
copper
access network

23. Fiber To The Premises core
we can implement point-to-multipoint topology purely in optics
but we need a fiber (pair) to each end user
requires 2 N optical transceivers
complex and costly to maintain
N end users
core
access network

24. An obvious solution core deploy intermediate switches
(active) switch located at curb or in basement
saves space at central office
need 2 N + 2 optical transceivers
core
N end users
feeder fiber
fiber
access network

25. The PON solution
another alternative - implement point-to-multipoint topology purely in optics
avoid costly optic-electronic conversions
use passive splitters – no power needed, unlimited MTBF
only N+1 optical transceivers (minimum possible) !
1:2 passive splitter
1:4 passive splitter
N end users
feeder fiber
core
access network
typically N=32
max defined 128

26. PON advantages
Shared infrastructure translates to lower cost per customer
minimal number of optical transceivers
feeder fiber and transceiver costs divided by N customers
greenfield per-customer cost similar to UTP
Passive splitters translate to lower cost
can be installed anywhere
no power needed
essentially unlimited MTBF
Fiber data-rates can be upgraded as technology improves
initially 155 Mbps
then 622 Mbps
now 1.25 Gbps
soon 2.5 Gbps and higher

27. PON architecture

28. Terminology
Like every other field, PON technology has its own terminology
the CO head-end is called an OLT
ONUs are the CPE devices (sometimes called ONTs in ITU)
the entire fiber tree (incl. feeder, splitters, distribution fibers) is an ODN
all trees emanating from the same OLT form an OAN
downstream is from OLT to ONU (upstream is the opposite direction)
downstream
Optical Network Units
upstream
Optical Distribution Network
NNI
Terminal Equipment
UNI
core
splitter
Optical Line Terminal
Optical Access Network

29. PON types
many types of PONs have been defined
APON ATM PON
BPON Broadband PON
GPON Gigabit PON
EPON Ethernet PON
GEPON Gigabit Ethernet PON
CPON CDMA PON
WPON WDM PON
in this course we will focus on GPON and EPON (including GEPON) with a touch of BPON thrown in for the flavor

30. Bibliography BPON GPON EPON BPON is explained in ITU-T G.983.x
GPON is explained in ITU-T G.984.x
EPON is explained in IEEE clauses 64 and 65
(but other clauses are also needed)
BPON
GPON
EPON

31. PON principles (Almost) all PON types obey the same basic principles
OLT and ONU consist of
Layer 2 (Ethernet MAC, ATM adapter, etc.)
optical transceiver using different ls for transmit and receive
optionally: Wavelength Division Multiplexer
downstream transmission
OLT broadcasts data downstream to all ONUs in ODN
ONU captures data destined for its address, discards all other data
encryption needed to ensure privacy
upstream transmission
ONUs share bandwidth using Time Division Multiple Access
OLT manages the ONU timeslots
ranging is performed to determine ONU-OLT propagation time
additional functionality
Physical Layer OAM
Autodiscovery
Dynamic Bandwidth Allocation

32. GPON, xGPON, Radio over Fiber
Dr. Erna Sri Sugesti

33. Background

38. PON Technology development

51. APON/BPON AND G-PON

52. ATM-PON and ITU-T G.983
All ITU PON standards feature three classes of optical transmission layer designs with different ODN (Optical Distribution Network) attenuations between ONU and OLT. The three classes are specified in ITU-T G.982 as:
Class A: 5–20 dB
Class B: 10–25 dB
Class C: 15–30 dB
Class C design is a very demanding power budget requirement for a passive fiber plant. For practical implementation yield and cost reasons, Class B+ with 28-dB attenuation was later introduced by most PON transceiver vendors

54. G-PON and ITU-T G.984
To better cope with the changes in communication technologies and meet fast-growing demand, ITU-T created the G.984 series standards for PONs with Gigabit capabilities, or G-PON
ITU-T G gives a high-level overview of G-PON components and reference structure. G-PON PMD layer or transceiver requirements are covered by the ITU-TG standard. Similar to APON, G-PON also defined single-fiber and dual-fiber PMDs. The bit rates defined in G.984 are:
Downstream: Mbps/ Mbps
Upstream: Mbps/ Mbps/ Mbps/ Mbps

55. As the bit rate advances into the gigabit regime, PON optical layer starts to become challenging.
First, to cover the full 20-km transmission distance, multilongitudinal-mode (MLM) lasers cannot be used at ONU any more in order to avoid excessive dispersion penalty.
Second, to cover the loss budget requirements for Class B (10–25 dB) and Class C (15–30 dB) fiber plants, more sensitive avalanche photo-diodes (APDs) are required instead of the lower cost PIN receivers. Without proper protection circuits, APDs are susceptible to damages due to avalanche breakdown if the inputs optical power becomes too high.

56. XGPON

58. XG-PON means
Full compatibility with G-PON — by virtue of a wavelength plan, blocking filters and loss budget that allow coexistence on a common PON infrastructure
Support for single-sided and mid-span reach extension, with reach of up to 60 km
Full service support — including voice, TDM, Ethernet (up to Gigabit rates), xDSL, wireless backhaul
Powerful Operation Administration Maintenance and Provisioning (OAM&P) capabilities providing a feature-rich service management system
Advanced security features including authentication, rogue detection and information privacy
Power-saving features on top of the already considerable power-efficient nature of fibre access

59. G.987 — 10-Gigabit-capable passive optical network (XG-PON) systems: Definitions, abbreviations and acronyms
Establishes common terms and acronyms used in the G.987 series, as well as delineates various optical access topologies.
G — 10-Gigabit-capable passive optical network (XG-PON) systems: General requirements Lists system-level requirements for XG-PON systems. Most significantly, the XG-PON system can coexist with a G-PON system on the same ODN. Provides examples of the wide variety of SNIs, UNIs and system configurations possible.
G — 10-Gigabit-capable passive optical network (XG-PON) systems: Physical media dependent (PMD) layer specification
Defines the physical layer interface specifications for the system operating at the nominal data rates of 10 Gbit/s downstream, 2.5 Gbit/s upstream.

60. Radio over Fiber

64. F. Aurzada, M. Scheutzow, M. Reisslein, N. Ghazisaidi, and M
F. Aurzada, M. Scheutzow, M. Reisslein, N. Ghazisaidi, and M. Maier, IEEECapacity and Delay Analysis of Next-Generation Passive Optical Networks (NG-PONs), IEEE TRANSACTIONS ON COMMUNICATIONS, VOL. 59, NO. 5, May 2011

65. References:
C. F. Lam, Passive optical networks : principles and practice, Elsevier, 2007.
Fiber in The Data Center II: Another Lightwave Study, Webinar, May 7, 2014
Some figures are downloaded from several sources in the internet