Fiber to the home (FTTH), also called fiber to the premises (FTTP), is the installation and use of optical fiber from a central point directly to individual buildings such as residences, apartment buildings and businesses to provide high-speed internet access. FTTH dramatically increases connection speeds available to computer users compared with technologies now used in most places.
FTTH promises connection speeds of up to 100 megabits per second (Mbps). These speeds are 20 to 100 times as fast as a typical cable modem or DSL (Digital Subscriber Line) connections. Implementing FTTH on a large scale would be costly because it requires installation of new cable sets over the "last links" from existing optical fiber cables to individual users. Some communities currently have fiber to the curb (FTTC) service. FTTC refers to the installation and use of optical fiber cable to the curbs near homes or businesses, with a "copper" medium carrying the signals between the curb and the end users.Content Continues Below
How does FTTH work?
The defining characteristic of FTTH is that it connects optical fiber directly to residences. It uses optical fiber for most or all of last-mile telecommunications. Optical fiber transmits data using light signals to achieve higher performance.
FTTH access networks are basically structured like this: fiber optic cables run from a central office, through a fiber distribution hub (FDH), then through a network access point (NAP), then finally into the home through a terminal that serves as a junction box.
The photo below shows a 'ditch witch' laying orange conduit. Once the conduit infrastructure is buried in place, optical fiber (which is string-like) will be pulled through the orange tubing from the network access point.
FTTH architecture and components
Two types of systems allow fiber optic cables to transmit data using light, making FTTH possible. They are active optical networks (AONs) and passive optical networks (PONs).
AONs use electrically powered switching equipment to actively direct signals to specific users. PONs use optical splitters to direct the signal instead of electrically powered switches, which means PON users only need electrically powered equipment on the receiving end of the network.
Both types are used in FTTH implementations and each have their benefits, but most FTTH implementations use PONs because they are cheaper to install and offer high performance. The network topology of PONs is as follows:
- An optical line terminal (OLT) at the provider's central office.
- Optical network units (ONUs) closer to the end user's premises.
- An optical distribution network (ODN) in between the OLT and ONU to split and distribute the signal traveling along the PON.
Benefits of using FTTH
The main benefit of FTTH is increased network performance, specifically higher speeds over a long distance, which the older method of using coaxial cables, twisted pair conductors and DSL cannot reach.
Because of its significantly higher bandwidth, FTTH is considered by experts as the best technology to handle consumer network demands in the coming decades. Some benefits that come with this include:
- Improved performance for high-definition video streaming on applications like YouTube and Roku.
- Allows for multiple upgrades without having to replace the fiber, leading some to call FTTH "future proof." The infrastructure surrounding the fiber can be updated without having to update the fiber itself.
- Higher speeds over longer distances than previous technologies.
- Better than other fiber configurations because fiber connects directly to residences and can complete remaining network segments with Ethernet or coaxial cable.
FTTH vs. FTTN, FTTC and more
FTTH is a more specific version of the term fiber to the x (FTTx), in which the x represents the point in the network at which a fiber optic cable connects to provide service to buildings in the vicinity. In each term, the place where optical fiber stops and transfers the signal to metallic cable begins differs. All versions of FTTx are the driving force behind next-generation access (NGA), which means an upgrade to the speed and quality of broadband networks.
Fiber to the home is named as such because the cable connects directly to the user's home. FTTB (fiber to the building) and FTTP (fiber to the premises) can be used interchangeably with FTTH, because the network structure is the same and the words home, building and premises are all used to describe the dwelling that the fiber networks connect directly to. A small distinction between FTTH and FTTB is that FTTH connects optical fibers directly to residences, of which there may be multiple in one building. In FTTB, the optical fibers connect to the building and then metallic cables connect to the individual units -- homes or offices -- inside.
FTTC, or fiber to the curb, is named as such because instead of connecting directly to a building, home or premises, the fiber optic cable connects to the curb near homes or businesses, where a twisted pair connection transfers the signal from the curb into the building to the end users. Fiber to the node (FTTN) refers to a setup in which the optical fiber connects to the network cabinet or node and passes the signal to copper wire at that point.
Several other versions of FTTx exist, including:
- Fiber to the terminal (FTTT). Fiber optic cables connect directly to desktop equipment in an office.
- Fiber to the office (FTTO). Similar to FTTT, fiber optic cable connects to a mini switch at users' desks in an office. There are usually several switches throughout the office, managed from one central location.
- Fiber to the street (FTTS). FTTS falls between FTTB and FTTC; it transitions to copper wire closer than FTTC but farther away than FTTB, which attaches directly to the building.
- Fiber to the distribution point (FTTdp). FTTdp is a mix between FTTC and FTTN. The end of fiber connects to the last possible distribution point before the end user's premises.
There are many other acronyms in the FTTx category, but the only major distinction between them is the point at which the fiber cabling ends and the metallic wiring begins.
One term that differs slightly from FTTH is fixed wireless, which, instead of switching from fiber optics to a metallic cable at the fiber endpoint, transmits a wireless signal into the home. This eliminates the need for cabling at the last segment of the network, where the most cost is incurred in installation.
The evolution of FTTH
FTTH has grown since the 1980s to accommodate the growing network demands of the modern world. Many fiber cables implemented in the 1980s are still in use today, which is a testament to their flexibility over time. Since the 1980s, fiber technology has become easier to install and cheaper than it was. Today, usage of FTTH and fiber optics continues to increase.