The Fiber Optic Association, Inc. the non-profit professional society of fiber optics Reference Guide To Fiber Optics

Topic: FTTH PON Types

Table of Contents: The FOA Reference Guide To Fiber Optics

Fiber To The Home PON Types FTTH PON: Passive Optical Network   A PON system utilizes a passive splitter that takes one input and splits it to broadcast to as many as 64 users to cut the cost of the links susbstantially by sharing one expensive laser with up to 32 homes.  Triple Play Systems    Most FTTH systems are so-called "triple play" systems offering voice (telephone), video (TV) and data (Internet access.) To provide all three services over one fiber, signals are sent bidirectionally over a single fiber using several wavelengths of light.      BPON, or broadband PON, is the most popular current PON application. BPON uses ATM as the protocol. ATM is widely used for telephone networks and the methods of transporting all data types (voice, Internet, video, etc.) are well known. BPON operates at ATM rates of 155, 622 and 1244 Mb/s.        Downstream digital signals from the CO through the splitter to the home are sent at 1490 nm. This signal carries both voice and data to the home. Video on most current systems uses the same technology as CATV, an analog modulated signal, broadcast separately using a 1550 nm laser which may require a fiber amplifier to provide enough signal power to overcome the loss of the optical splitter. Upstream digital signals for voice and data are sent back to the CO from the home using an inexpensive 1310 nm laser. WDM couplers separate the signals at both the home and the CO. BPON architecture    GPON, or gigabit-capable PON, uses an IP-based protocol and either ATM or GEM (GPON encapsulation method) encoding. Data rates of up to 2.5 Gb/s are specified and it is very flexible in what types of traffic it carries. GPON enables “triple play” (voice-data-video) and is the basis of most planned FTTP applications in the near future. In the diagram above, one merely drops the AM Video at the CO and carries digital video over the downstream digital link.    EPON or Ethernet PON is based on the IEEE standard for Ethernet in the First Mile. It uses packet-based transmission at 1 Gb/s with 10 Gb/s under discussion. EPON is widely deployed in Asia. The system architecture is the same as GPON but data protocols are differenet. PON System Specification Summary x BPON GPON EPON Standard ITU-T G.983 ITU-T G.984 IEEE 802.3ah (1 Gb/s) IEEE 802.3av (10Gb/s) Downstream Bitrate 155, 622 Mb/s, 1.2 Gb/s 155, 622 Mb/s, 1.2, 2.5 Gb/s 1.25 Gb/s, 10.3 Gb/s Upstream Bitrate 155, 622 Mb/s 155, 622 Mb/s, 1.2, 2.5 Gb/s 1.25 Gb/s, 1.25 or 10.3 Gb/s Downstream Wavelength 1490, 1550 1490 1490, 1550 Upstream Wavelength 1310 1310 1310 Protocol ATM Ethernet over ATM/IP or TDM Ethernet Video RF at 1550 or IP at 1490 RF at 1550 or IP at 1490 IP Video Max PON Splits 32 64 16 Coverage <20 km <60 km <20 km      RFOG: CATV's FTTH CATV operators need something to combat their subscriber’s clamoring for fiber to the home, which has lead to the development of RFOG, "RF over Glass." CATV standards have looked at PON architectures and the SCTE has proposed a standard for deploying a broadcast architecture of analog signals similar to PONs called RFoG for RF (radio frequency - i.e. FM) over Glass. RFOG is basically nothing more than an all-fiber HFC/cable modem system built with less expensive components now available thanks to the volume pricing of components used in FTTH. It’s designed to operate over a standard telco PON (passive optical network) fiber architecture with short fiber lengths and including the losses of a FTTH PON splitter. There is one interesting side effect of this approach. Now telcos and CATV companies can deliver the same services over the same cable plant using totally different technologies. But that means that office or apartment building owners, developers or even whole towns that might be considering installing FTTH infrastructure themselves and leasing the fiber to a service provider can have a choice of service providers. One cable network can support either CATV or telco systems – or even someone else for that matter. That opens up a big market for private fiber optic systems. Technical Information on FTTX  From The FOA Online Reference Guide:  FTTH   FTTH Architectures   FTTH PON Protocols   Testing FTTH Networks    FTTx Online Tutorial Here's links for more information on FTTx Training & Certification FOA Certification Overview FOA FTTx Certification Requirements FOA-Approved Training Programs  Table of Contents: The FOA Reference Guide To Fiber Optics

 

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