The Ultimate Guide to FTTH

FTTH (Fiber to the home) is an optical fiber communication transmission method. It directly connects the optical fiber to the user terminal.
Table of Contents

You may need a comprehensive introduction to FTTH technology,

which helps you quickly understand the basics of FTTH.

This blog is right aims to solve this problem, let’s read and learn~

1. What is FTTH?

FTTH (Fiber to the home) is an optical fiber communication transmission method.

It directly connects the optical fiber to the user terminal.

FTTH is an access method in FTTx, so what is FTTx?

FTTX is a general term for various application types of broadband optical access networks.

There are many variants of “X” like the followings:

  • Fiber to the building (FTTB)
  • Fiber to the cross box (FTTCab)
  • Fiber to the curb (FTTC)
  • Fiber to the Desktop (FTTD)
  • Fiber to the Home (FTTH)
  • Fiber to the Premises (FTTP)
  • Fiber to the Office (FTTO)
  • Fiber to the User (FTTU)

FTTx technology ranges from central office equipment to user terminal equipment, including:

  • optical line terminal OLT (Optical Line Terminal),
  • optical network unit ONU (Optical Network Unit),
  • optical network terminal ONT (Optical Network Terminal).

The terminal connected to FTTH is called Optical Network Terminal (ONT).

The FTTB or FTTC is connected to the building (Building) or the curb (Curb) through the optical fiber network,

Then connect to the terminal via a copper twisted pair network or wirelessly,

The end equipment of a fiber optic network is called an Optical Network Unit (ONU).

The ONU is connected to the network terminal (NT) through a copper twisted pair network or wirelessly.

FTTCab is similar to FTTC except that its ONU is located in Cabinet.

FTTB, FTTC, and FTTCab are all “partial” fiber to the home,

That is to say, the optical fiber is not directly connected to the end user, but reaches the vicinity of the end user. It is then connected to the end user via a twisted pair network.

In FTTCab, the ONU in the telecommunication junction box is usually 1000-2000m away from the end user.

In this case, one ONU unit can support about 500 end users.

In FTTC, the ONU is closer to the end user, 200-1000m, and can support 8 to 32 end users.

The network between OLT and ONT/ONU is called an optical distribution network ODN, and its distance can reach 20km.

2. FTTH market situation

At the 2020 FTTH Virtual Conference on December 3, IDATE and the European FTTH Council compiled FTTH market forecast data for 2020-2026.

Data show that by 2026, the number of users in 27+ EU and UK countries will further increase to about 148 million.

The number of users in 38+ EU and UK countries will reach about 208 million,

In 2026, the FTTH/B coverage rate will reach 73.3%, a significant increase from 23.4% in 2012.

The number of users in some countries is expected to surge from 2019,

For example, Germany increased by +730%, the United Kingdom increased by +548%, and Italy increased by +218%.

In terms of country rankings, Russia is likely to continue to lead,

But Germany is expected to move up to second in 2026 and eighth in 2020.


3. FTTH fiber access technology

FTTH is a mature optical fiber access technology.

There are two commonly used fiber access technologies, P2P (point-to-point technology) and P2MP (point-to-multipoint PON).

P2P (Peer-to-peer) is a peer-to-peer network technology.

It allows two users without public IP to communicate directly.

PON (Passive Optical Network) is a passive optical network,

Refers to the connection between the OLT (Optical Line Terminal) and the ONU (Optical Network Unit).

ODN (Optical Distribution Network) does not have any active equipment,

Use only fiber optics and passive components.

PON mainly adopts a point-to-multipoint network structure, which is the main technology to realize FTTB/FTTH.

At present, the PON technologies that have commercially implemented FTTX can be divided into the following three types:

Narrowband PON Technology for Narrowband TDM Service Access

BPON (APON) is based on ATM transmission for broadband access, EPON technology is based on Ethernet packet transmission

Taking into account the integrated GPON technology of ATM/Ethernet/TDM.

4. What is ODN?

ODN is an optical distribution network, which is the optical transmission physical channel between the OLT and the ONU.

The main function is to complete the bidirectional transmission of optical signals.

It usually consists of fiber optic cables, optical connectors, optical splitters, and supporting equipment for installing and connecting these devices

The most important component in it is the beam splitter.

Optical distribution network (ODN) has two main modes of light splitting: primary splitting and secondary splitting.

The structure of the first-order splitting is OLT-optical splitter-ONU,

The optical splitters from the OLT to the ONU are all in parallel.

When one-stage light splitting is used, the splitter is generally set at the intersection of the wiring light.

The structure of the two-stage optical splitting is OLT-optical splitter 1-optical splitter 2-ONU, and the optical splitters between the OLT and the ONU are cascaded.

When two-stage optical splitting is used, the first-stage splitter is generally set at the intersection of the wiring light, and the second-stage splitter is generally set at the fiber splitter box.

Only one beam splitter can be connected to the first-order beam splitter.

Generally, a splitter with a large number of splits is used, such as 1:32 or 1:64.

Generally, a 1:8 or 1:16 splitter is used at the first-level splitting point, and a 1:4 or 1:8 splitter is used at the second-level splitting point.

Typically, primary splitting solutions are used in congested downtown or town areas.

The aim is to reduce costs and ease the maintenance of Optical Distributed Network (ODN) nodes.

On the other hand, secondary beam-splitting solutions are used in roadside or rural locations

The purpose is to cover a wide range of ODN nodes, save resources and save money.

5. The working principle of the optical splitter

An optical splitter is a core passive device in the FTTH system.

An optical splitter also called an optical beam splitter, is an integrated waveguide optical power distribution device.

It can split an input optical signal into two or more output optical signals,

Optical input power is evenly distributed across all output ports.

For example, an optical splitter with a split ratio of 1:4 can equally divide an optical signal into four parts and transmit them in four different channels.

At present, the splitting ratio of the optical splitter is generally 1:N or 2:N,

Such as 1:4, 1:8, 1:16, 1:32, 2:16, 2:32.

The working principle of the optical splitter is:

When a single-mode fiber transmits an optical signal,

The energy of light is not completely concentrated in the core to propagate,

A small amount propagates through the cladding close to the core.

That is if the cores of the two fibers are close enough,

The mode field of light transmitted in one fiber can enter another fiber,

The optical signal is redistributed among the two fibers.

6. Optical splitter VS WDM wavelength division multiplexer

The working principle of the WDM wavelength division multiplexer is divided into two steps

① Combine a series of optical signals carrying information but with different wavelengths into a bundle and transmit along a single fiber.

②At the receiving end, use some method to separate the optical signals of different wavelengths.

This technology can transmit multiple signals on one fiber at the same time,

Each signal is transmitted by a certain wavelength of light, which is a wavelength channel. In the same fiber, two or more optical wavelength signals can transmit information through different optical channels at the same time.

It is called optical wavelength division multiplexing technology WDM.

The splitter divides the light of one wavelength into multiple beams according to the use.

7. Classification of Optical Splitters

According to the different spectroscopic principles and manufacturing processes,

optical splitters can be divided into two types:

fused taper type (FBT) and planar waveguide type (PLC).

  • PLC Optical Splitter

Planar waveguide optical splitter (PLC Splitter) is an integrated waveguide optical power distribution device based on a quartz substrate.

Its main function is to divide the optical signal from one optical fiber into multiple optical fibers.

The device is composed of an optical splitter chip coupled with an optical fiber array at both ends,

The chip is the core component, and the quality of the chip and the split channel directly affect the price of the entire splitter.

The chip has one input and N output waveguides.

The optical fiber array is located on the upper surface of the chip, and the casing is sealed to form an optical splitter with one input and N output fiber.

  • Fused Tapered (FBT) Optical Splitter

The fusion taper technique is to bundle two or more optical fibers with the coating removed,

Then it is melted and stretched on the cone drawing machine, and the chain of the splitting ratio is monitored in real-time,

After the spectroscopic ratio reaches the requirement, the melting and stretchier are terminated.

One end of the fiber keeps one fiber (the rest is cut off) as the input end,

The other end is used as a multi-channel output.

  • FBT vs PLC

The distribution method of the splitting ratio is also one of the main differences between the two.

The splitting variability of the taper splitter is the biggest advantage of this device.

The splitting of PLC splitter is equally divided, and the signal can be evenly distributed to the users.

For example, a 1×32 PLC splitter can divide the optical signal into 32 equal parts,

It is then transmitted within 32 different channels.

Sometimes, due to inconsistencies in the number and distance of users,

It is necessary to distribute the optical power of different lines,

At this time, devices with different split ratios are required, and FBT splitters are used.

Fibconet started as a professional plc splitter factory In 1994.

Today we are still the top3 PLC/FBT splitter suppliers in China.

With the improvement of Fibconet production technology

And the growing FTTx products requirement of our customers

We have developed and integrated the entire FTTx supply chain to meet your one-stop service needs.

We can not only offer you the best prices for PLC splitters and FBT splitters.

But also consider your specific needs and propose a variety of plans and quotations for FTTx construction.

Be free to contact us for our new future!

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