You Need to Know About Fiber Optic Connectors
December ,02 ,2025
Fiber optic connectors used to be bulky and hard to handle. But as manufacturers have standardized and simplified them, today’s versions work better and are much easier to use. This growing user-friendliness has made fiber optic systems more popular than ever. In this guide, we’ll take a quick look at the current fiber optic connector market and dive deep into what these connectors are all about.
In recent years, the global market has been boosted by the growing use of fiber optic technology. Fiber optic cables now often replace copper cables in many scenarios—and that’s great news for the fiber optic connector market. Below is a bar chart from Grand View Research, showing how popular connector types like LC, SC, and MTP have grown in recent years.
You can easily see from the chart that these five common fiber optic connectors are all on a steady upward trend. Specifically, LC connectors will keep leading the optical connector market for years to come. Meanwhile, demand for MTP/MPO connectors has been picking up lately, which suggests they might grab a bigger share of the market soon.
To sum up, this overall growth shows that demand for fiber connectors stays strong, and the market is evolving fast. High-density, high-quality options like LC connectors remain a top pick for many users. And with high-bandwidth 100G/200G/400G networks and 5G becoming more common, multi-fiber connectors—such as MTP/MPO connectors and even Rosenberger’s Q-RMC connectors—are likely to gain more attention.
We can expect that as the need for efficient cabling and cable management grows, fiber optic connectors that are easy to install, have low signal loss, and perform well will keep being the trend in optical communications.
A fiber optic connector (also called an optical fiber connector) is a part that caps the end of a fiber optic cable, letting you connect or disconnect it faster than fiber splicing. It uses mechanical parts to line up the fiber cores, so light can pass through smoothly. That’s why these connectors play a big role in how reliable fiber optic transmission is and how well the whole system works. Usually, good-quality connectors lose very little light, even if there’s some reflection or misalignment of the fibers.
As key optical parts, fiber optic connectors follow multiple standards in telecom cabling and electrical engineering. Here’s a table with some of the main standards they adhere to:
TIA/EIA: TIA/EIA-4750000-B: General Rules for Fiber Optic ConnectorsTIA/EIA-604: Fiber Optic Connector Intermateability Standards (FOCIS)TIA/EIA-568-B.3/C.0/C.3: Fiber Optic Standards for Commercial Buildings
Telcordia: GR-326: Basic Requirements for Single Mode Fiber Optic ConnectorsGR-1435: Basic Requirements for Multi-Fiber Optic Connectors
IEEE: IEEE 802.3: Standards for CSMA/CD Access and Physical Layer (Carrier Sense Multiple Access with Collision Detection)IEEE 802.3ae: 10 Gigabit Ethernet over Fiber Optic (Single Mode & Multimode)IEEE 802.3aq: 10 Gigabit Ethernet over Installed Multimode Fiber Optic
Every fiber optic connector has five key parts: the fiber ferrule, sub-assembly body, connector housing, fiber cable, and stress relief boot. Let’s use an SC connector as an example to break down its structure.
The main traits of fiber connectors include optical performance, interchangeability, repeatability, reliability, and number of insertions.
Optical Performance: The two most important metrics here are insertion loss and return loss. Smaller insertion loss is better—any good connector should have insertion loss below 0.5dB. On the other hand, higher return loss means better performance. Typically, a connector’s return loss shouldn’t be less than 25dB, but in practice, polishing makes it at least 45dB. For more details on these two metrics, check out the guide “Insertion Loss and Return Loss for Fiber Connectors.”
• Interchangeability & Repeatability: Fiber optic connectors are universal passive parts. You can mix and match the same type of connector any way you want, and use them over and over again.
• Reliability: Sometimes fiber connectors need to be installed underground or on outdoor walls. In these tough conditions, you need reliable connectors to keep the optical transmission smooth.
• Durability: Most connectors can be plugged in and out over 1,000 times. So an easy-to-use connector saves you a lot of installation time and boosts work efficiency.
You can categorize fiber optic connectors in various ways. By the end face of the pin, they’re divided into PC, UPC, and APC. By the transmission medium, they’re either single-mode or multimode. While many types of fiber connectors are available, only a few dominate the market—like LC, SC, FC, ST, and MTP/MPO connectors.
The connectors listed above are common ones that need an adapter panel to connect. They’re widely used in data centers, telecom rooms, server farms, cloud storage networks, and more. But Rosenberger has two new, tough industrial connectors: Q-RMC and NEX10 fiber optic connectors. These use a push-pull quick-lock design, making them easy to install. Both Q-RMC and NEX10 are built for harsh environments, so they’re recommended for industrial sites, mines, mobile communications (FTTA), 5G base stations, and similar places. Click here for a full guide to fiber optic connector types.
VOSCOM's 12G-SDI Fiber Extender & 3G-SDI Fiber Optic Extender series, if the device directly with the SFP, only can support LC fiber optic connector, and others can support all connnectors, FC, ST, LC or SMPTE 304M hybrid connectors.
and the Audio over Fiber, contact closure over fiber series, also support all fiber optic connector types, customer can choose which they need.
Only the light that enters the core of the receiving fiber will travel through it. The rest of the light doesn’t pass through the connection—it leaks out of the fiber. Ideally, if the two fiber cores are the same and perfectly aligned, and the connectors or splices are well-made and clean, loss will be as low as possible. But in reality, both fibers and connectors have small manufacturing differences that prevent perfect alignment.
Many things cause loss in connectors and splices. For example, gaps between the fiber ends affect both insertion loss and return loss. That’s why fiber connectors use different polishing techniques to make sure the fiber ends touch physically, which cuts down on back reflection.
Also, light from a fiber with a larger numerical aperture (NA) is more sensitive to angle misalignment and end gaps. So when light travels from a fiber with a large NA to one with a small NA, there’s more loss than the other way around. In short, connecting larger fibers to smaller ones leads to significant loss—not just because the smaller fiber has a thinner core, but also because most small-core fibers have a smaller NA.
Basically, fiber optic cables with connectors are mainly used in telecommunications—from small and medium offices to large-scale data centers. As the chart below shows, telecom has the biggest share of the market in terms of revenue. What’s more, growing demand for 5G networks, 100/200/400G high-speed transmission, and cloud-based apps will push demand even higher. The fast-growing IT industry around the world still needs more energy-efficient, affordable, and high-quality network infrastructure—and that means more fiber connectors.
Besides telecom, sectors like oil and gas, military and aerospace, and healthcare are also set to grow a lot. This is because multimode fiber and Plastic Optical Fiber (POF) are being used more in these fields. For example, the military uses fiber connector technology for many ground, sea, air, and space uses—like in avionics testing equipment and ground support systems for fighter jets.
For 125um single-mode fiber, 126um is the recommended ferrule hole size. You can find 125.5um ferrules for situations where alignment needs to be perfect, but the 126um hole leaves room for epoxy around the fiber, so you can insert it without breaking it.
Tests usually fall into two categories: field testing and factory testing. In factories, a profiling system checks that the overall polished shape of the connector is correct. An optical microscope is also used to look for flaws. In the field, a special handheld optical microscope checks for dirt and flaws, and other tests are done to measure key parameters.
You can buy fiber patch cables in different setups (like SC-SC or SC-LC). The type of equipment you’re installing will decide which connector you need. There are also many adapters and patch cable setups that let you connect fiber-based equipment.
Whenever a connector isn’t connected, put a cap on it to keep dirt off the ferrule end. Before connecting or testing, it’s best to clean both ends with lint-free wipes dampened with isopropyl alcohol. There are special cleaners, wipes, and swabs for this—following the manufacturer’s cleaning instructions is always a good idea. The “Fiber Connector Cleaning Tutorial” will show you how to do it properly.
A Quick Look at the Fiber Optic Connector Market
In recent years, the global market has been boosted by the growing use of fiber optic technology. Fiber optic cables now often replace copper cables in many scenarios—and that’s great news for the fiber optic connector market. Below is a bar chart from Grand View Research, showing how popular connector types like LC, SC, and MTP have grown in recent years.
To sum up, this overall growth shows that demand for fiber connectors stays strong, and the market is evolving fast. High-density, high-quality options like LC connectors remain a top pick for many users. And with high-bandwidth 100G/200G/400G networks and 5G becoming more common, multi-fiber connectors—such as MTP/MPO connectors and even Rosenberger’s Q-RMC connectors—are likely to gain more attention.
We can expect that as the need for efficient cabling and cable management grows, fiber optic connectors that are easy to install, have low signal loss, and perform well will keep being the trend in optical communications.
The Basics of Fiber Optic Connectors
What Is a Fiber Optic Connector?
A fiber optic connector (also called an optical fiber connector) is a part that caps the end of a fiber optic cable, letting you connect or disconnect it faster than fiber splicing. It uses mechanical parts to line up the fiber cores, so light can pass through smoothly. That’s why these connectors play a big role in how reliable fiber optic transmission is and how well the whole system works. Usually, good-quality connectors lose very little light, even if there’s some reflection or misalignment of the fibers.
Standards for Fiber Optic Connectors
As key optical parts, fiber optic connectors follow multiple standards in telecom cabling and electrical engineering. Here’s a table with some of the main standards they adhere to:
TIA/EIA: TIA/EIA-4750000-B: General Rules for Fiber Optic ConnectorsTIA/EIA-604: Fiber Optic Connector Intermateability Standards (FOCIS)TIA/EIA-568-B.3/C.0/C.3: Fiber Optic Standards for Commercial Buildings
Telcordia: GR-326: Basic Requirements for Single Mode Fiber Optic ConnectorsGR-1435: Basic Requirements for Multi-Fiber Optic Connectors
IEEE: IEEE 802.3: Standards for CSMA/CD Access and Physical Layer (Carrier Sense Multiple Access with Collision Detection)IEEE 802.3ae: 10 Gigabit Ethernet over Fiber Optic (Single Mode & Multimode)IEEE 802.3aq: 10 Gigabit Ethernet over Installed Multimode Fiber Optic
What’s the Structure of a Fiber Optic Connector?
Every fiber optic connector has five key parts: the fiber ferrule, sub-assembly body, connector housing, fiber cable, and stress relief boot. Let’s use an SC connector as an example to break down its structure.
1. Fiber Ferrule
An SC fiber optic connector features a long, cylindrical ferrule that’s 2.5mm wide. It’s usually made of ceramic (zirconia) or metal (stainless steel alloy). A tiny, precise hole—between 124um and 127um wide—is drilled through its center. You strip the outer layer off the fiber, slide the bare part into this hole, and usually hold it in place with epoxy or glue. The end of the fiber lines up with the end of the ferrule, which is then polished until it’s smooth.2. Sub-Assembly Body
The ferrule fits inside the SC sub-assembly body, which has parts to keep the cable and fiber secure. The end of the ferrule sticks out of the sub-assembly body so it can connect with another SC connector inside a mating sleeve (also called an adapter or coupler).3. Connector Housing
The connector housing wraps around the sub-assembly body. It has a clip mechanism that locks into the mating sleeve (adapter), keeping the connector firmly in place.4. Fiber Cable
The fiber cable and its strength parts (like aramid yarn or Kevlar) are crimped onto the sub-assembly body with a metal ring. This makes the connector stronger for handling and protects the fiber inside at the same time.5. Stress Relief Boot
The stress relief boot covers the spot where the connector body meets the cable, protecting the cable from damage. The design of this boot differs depending on whether the fiber is 900um tight-buffered fiber or 1.6mm to 3mm fiber cable.
Key Traits of Fiber Optic Connectors
The main traits of fiber connectors include optical performance, interchangeability, repeatability, reliability, and number of insertions.
Optical Performance: The two most important metrics here are insertion loss and return loss. Smaller insertion loss is better—any good connector should have insertion loss below 0.5dB. On the other hand, higher return loss means better performance. Typically, a connector’s return loss shouldn’t be less than 25dB, but in practice, polishing makes it at least 45dB. For more details on these two metrics, check out the guide “Insertion Loss and Return Loss for Fiber Connectors.”
• Interchangeability & Repeatability: Fiber optic connectors are universal passive parts. You can mix and match the same type of connector any way you want, and use them over and over again.
• Reliability: Sometimes fiber connectors need to be installed underground or on outdoor walls. In these tough conditions, you need reliable connectors to keep the optical transmission smooth.
• Durability: Most connectors can be plugged in and out over 1,000 times. So an easy-to-use connector saves you a lot of installation time and boosts work efficiency.
Types of Fiber Optic Connectors
You can categorize fiber optic connectors in various ways. By the end face of the pin, they’re divided into PC, UPC, and APC. By the transmission medium, they’re either single-mode or multimode. While many types of fiber connectors are available, only a few dominate the market—like LC, SC, FC, ST, and MTP/MPO connectors.
Fiber Optic Connectors Compatible with VOSCOM's Fiber Optic extender series
VOSCOM's 12G-SDI Fiber Extender & 3G-SDI Fiber Optic Extender series, if the device directly with the SFP, only can support LC fiber optic connector, and others can support all connnectors, FC, ST, LC or SMPTE 304M hybrid connectors.
and the Audio over Fiber, contact closure over fiber series, also support all fiber optic connector types, customer can choose which they need.
Coupling Loss in Fiber Connectors
Only the light that enters the core of the receiving fiber will travel through it. The rest of the light doesn’t pass through the connection—it leaks out of the fiber. Ideally, if the two fiber cores are the same and perfectly aligned, and the connectors or splices are well-made and clean, loss will be as low as possible. But in reality, both fibers and connectors have small manufacturing differences that prevent perfect alignment.
Many things cause loss in connectors and splices. For example, gaps between the fiber ends affect both insertion loss and return loss. That’s why fiber connectors use different polishing techniques to make sure the fiber ends touch physically, which cuts down on back reflection.
Also, light from a fiber with a larger numerical aperture (NA) is more sensitive to angle misalignment and end gaps. So when light travels from a fiber with a large NA to one with a small NA, there’s more loss than the other way around. In short, connecting larger fibers to smaller ones leads to significant loss—not just because the smaller fiber has a thinner core, but also because most small-core fibers have a smaller NA.
Uses for Fiber Optic Connectors
Basically, fiber optic cables with connectors are mainly used in telecommunications—from small and medium offices to large-scale data centers. As the chart below shows, telecom has the biggest share of the market in terms of revenue. What’s more, growing demand for 5G networks, 100/200/400G high-speed transmission, and cloud-based apps will push demand even higher. The fast-growing IT industry around the world still needs more energy-efficient, affordable, and high-quality network infrastructure—and that means more fiber connectors.
Besides telecom, sectors like oil and gas, military and aerospace, and healthcare are also set to grow a lot. This is because multimode fiber and Plastic Optical Fiber (POF) are being used more in these fields. For example, the military uses fiber connector technology for many ground, sea, air, and space uses—like in avionics testing equipment and ground support systems for fighter jets.
Frequently Asked Questions (FAQs)
For 125um fibers, should I choose a 125.5um or 126um hole ferrule? What’s the difference?
For 125um single-mode fiber, 126um is the recommended ferrule hole size. You can find 125.5um ferrules for situations where alignment needs to be perfect, but the 126um hole leaves room for epoxy around the fiber, so you can insert it without breaking it.
How are fiber connectors tested?
Tests usually fall into two categories: field testing and factory testing. In factories, a profiling system checks that the overall polished shape of the connector is correct. An optical microscope is also used to look for flaws. In the field, a special handheld optical microscope checks for dirt and flaws, and other tests are done to measure key parameters.
How do I choose the right fiber connector?
You can buy fiber patch cables in different setups (like SC-SC or SC-LC). The type of equipment you’re installing will decide which connector you need. There are also many adapters and patch cable setups that let you connect fiber-based equipment.
When and how should I clean fiber optic connectors?
Whenever a connector isn’t connected, put a cap on it to keep dirt off the ferrule end. Before connecting or testing, it’s best to clean both ends with lint-free wipes dampened with isopropyl alcohol. There are special cleaners, wipes, and swabs for this—following the manufacturer’s cleaning instructions is always a good idea. The “Fiber Connector Cleaning Tutorial” will show you how to do it properly.