fiber to the home (FTTH)

What is fiber to the home?

Fiber to the home (FTTH), also called fiber to the premises (FTTP), is the installation and use of optical fiber from a central point to individual buildings to provide high-speed internet access. FTTH dramatically increases connection speeds available to computer users compared to other technologies.

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 connections. It could be costly to implement FTTH on a large scale because it requires the 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) services. 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.

How does FTTH work?

The defining characteristic of FTTH is that it connects optical fiber directly to residences, apartment buildings and businesses. FTTH uses optical fiber for most or all last-mile telecommunications. Optical fiber transmits data using light signals to achieve higher performance.

In FTTH access networks, fiber optic cables run from a central office and through a fiber distribution hub. The cables then run through a network access point (AP) and finally into the home through a terminal that serves as a junction box.

FTTH architecture and components

Two types of systems enable fiber optic cables to transmit data using light and make FTTH possible: active optical networks (AONs) and passive optical networks (PONs).

AONs use electrically powered switching equipment to direct signals to specific users. Instead of electrically powered switches, PONs use optical splitters to direct signals. However, PONs still require electrically powered equipment at the source and receiving ends of the network.

Both types are used in FTTH implementations, and each has their benefits, but most FTTH implementations use PONs because they cost less to install and offer high performance.

The network topology of PONs consists of the following:

• 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 in between the OLT and ONU to split and distribute the signal traveling along the PON.

Benefits of FTTH

The main benefit of FTTH is increased network performance. FTTH provides higher speeds over longer distances that older coaxial cables, twisted-pair cables and DSL cannot reach. FTTH also offers significantly higher bandwidth than other connectivity methods.

Some benefits of FTTH's higher bandwidth capacity include the following:

• Improved performance for high-definition video streaming on applications like YouTube and Roku.
• Upgrades that don't require replacing the fiber. Network professionals can update the infrastructure surrounding the fiber without having to update the fiber itself.
• Higher speeds over longer distances than previous technologies.
• Better performance than other fiber configurations. Fiber directly connects to residences and can complete remaining network segments with Ethernet or coaxial cables.

Fiber to the x

FTTH is a 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, which means an upgrade to the speed and quality of broadband networks.

FTTH's name comes from the fact that the cable connects directly to the user's home. Network professionals often use the terms fiber to the building (FTTB) and fiber to the premises (FTTP) interchangeably with FTTH. The network structure is the same, and the words home, building and premises all describe dwellings to which fiber networks directly connect.

A small distinction between FTTH and FTTB is that FTTH connects optical fibers directly to residences, and one building could have multiple residencies. In FTTB, the optical fibers connect to the building and metallic cables connect to the individual units -- such as homes or offices -- inside.

Several other versions of FTTx exist:

• Fiber to the node (FTTN). A setup in which the optical fiber connects to the network cabinet or node and passes the signal to copper wire at that point.

• Fiber to the terminal (FTTT). Fiber optic cables connect directly to desktop equipment in an office.
• Fiber to the office. Similar to FTTT, a fiber optic cable connects to a mini switch at a users' desk in an office. The office usually has several switches throughout the building, managed from one central location.
• Fiber to the street (FTTS). FTTS falls between FTTB and FTTC; FTTS 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.

Many other acronyms in the FTTx category exist. But the only major distinction between them is the point at which the fiber cabling ends and the metallic wiring begins.

Fixed wireless differs slightly from FTTH. Instead of switching from fiber optics to a metallic cable at the fiber endpoint, fixed wireless transmits a wireless signal into the home. This eliminates the need for cabling at the last segment of the network, where most costs incur during installation.

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 cheaper and easier to install. Today, usage of FTTH and fiber optics continues to increase.

Editor's note: This article was reformatted to improve the reader experience.