Single-Mode And Multi-Mode Fiber Optic Cables

In the digital age, optical fiber technology has become one of the important pillars of modern communications. Among many fiber optic cables, single-mode optical fiber and multi-mode optical fiber are two common types that have attracted much attention. They have significant differences in structure, transmission characteristics, and application fields. Understanding and comparing them is crucial to deeply understanding the essence of optical fiber technology. Single-mode fiber plays an important role in long-distance communications with its fine structure and excellent performance, while multi-mode fiber is widely used in short-distance communications with its simple design and low cost. In this article, we will delve into the characteristics, differences, and respective advantages and disadvantages of these two fiber types, take you into the magical world of optical fiber, and explore the mysteries of single-mode and multi-mode optical fibers.

The structure of optical fiber cables is mainly divided into two types: single-mode optical fiber and multi mode optical fiber. They differ in fiber core diameter and working principle and are suitable for different communication needs. Single-mode fiber: Single-mode fiber has a fiber core diameter that is very small (usually 9 microns) and only allows optical signals to be transmitted in a single mode (i.e., only in one light wave mode). It is suitable for long-distance communication and high-speed data transmission, with high bandwidth and low dispersion. multi-mode fiber: multi-mode fiber has a larger fiber core diameter (usually 50 or 62.5 microns), allowing multiple light modes to propagate simultaneously. It is suitable for short-distance communication and local area network connections, with low cost but relatively low bandwidth.

What Is Single-mode Fiber?

Single Mode Fiber is an optical transmission medium used to transmit optical signals. Its core feature is that the fiber core has a very small diameter, typically 9 microns (or less). In single-mode fiber, the optical signal propagates in only one optical mode, which means that the light travels along one path inside the fiber core without scattering between modes.

The working principle of single-mode fiber is based on the phenomenon of total reflection of light. When light is incident from a medium with a lower refractive index (such as air) to a medium with a higher refractive index (such as the core of an optical fiber), if the incident angle is less than the critical angle, the light will undergo total reflection and be completely reflected within the boundary. There will be no refraction. This phenomenon allows optical signals to be transmitted inside the fiber core without being lost during transmission. Since the core diameter of single-mode fiber is very small, optical signals hardly scatter and dispersion occur during transmission. Therefore, it has low attenuation and dispersion and is suitable for long-distance communication and high-speed data transmission. Single-mode fiber usually uses a laser or laser diode as the light source. Commonly used wavelengths include 1310 nanometers and 1550 nanometers.

In the field of communications, single-mode optical fiber is widely used in long-distance optical fiber communication systems, such as metropolitan area networks, wide area networks, optical fiber interconnections, etc. Its advantages include high bandwidth, low loss, strong anti-interference ability, etc. The development and application of single-mode optical fiber has promoted the development of optical fiber communication technology and plays an important role in modern communication networks.

What Is Multi-Mode Fiber?

Multi-mode fiber is an optical transmission medium used to transmit optical signals. Compared with single-mode fiber, the core feature of multi-mode fiber is its relatively larger core diameter, usually 50 or 62.5 microns. Multimode optical cables follow the ISO 11810 standard. Multimode optical fibers are divided into OM1, OM2, OM3, OM4 and OM5 optical fibers. In multi-mode fiber, light signals can propagate in multiple light modes, which means that light can travel along different paths within the fiber core.

The working principle of multimode fiber is similar to that of single-mode fiber, which is also based on the phenomenon of total reflection of light. When optical signals pass through multi-mode optical fibers, due to the larger fiber core, the optical signals can propagate in many different modes. Interactions occur between these modes, resulting in scattering and dispersion of the optical signal during transmission. Due to the large core diameter of multimode optical fiber, optical signals will interact and be dispersed during transmission, resulting in large attenuation. Therefore, the transmission distance of multi-mode fiber is usually shorter than that of single-mode fiber, and its bandwidth is relatively low. Multimode optical fiber usually uses LED (Light Emitting Diode) or VCSEL (Vertical Cavity Surface Emitting Laser) as the light source. Commonly used wavelengths include 850 nanometers and 1300 nanometers.

In the field of communications, multimode optical fiber is usually used for short-distance communications and local area network connections, such as office internal networks, data center internal connections, etc. It has the characteristics of low cost, easy installation and maintenance, and is suitable for application scenarios that do not require high bandwidth. Multimode optical fiber is widely used in environments such as local area networks and data centers, providing a reliable solution for data transmission.

Single Mode Fiber VS Multimode

1. Core diameter:

Single-mode optical fiber: The core diameter is usually 9 microns (μm), which is very narrow.

Multi mode optical fiber: The core diameter is usually 50 or 62.5 micrometers (μm), which is relatively large.

2. Transmission mode:

Single-mode fiber: Light signals travel in a single mode, i.e., only in one mode along the fiber.

multi-mode fiber: Light signals propagate in multiple modes, and light can travel in multiple paths within the fiber core.

3. Wavelength and light source:

Single-mode fiber: Lasers or laser diodes are usually used as light sources. Commonly used wavelengths include 1310 nanometers and 1550 nanometers.

Multimode optical fiber: LED (Light Emitting Diode) or VCSEL (Vertical Cavity Surface Emitting Laser) is usually used as the light source. Commonly used wavelengths include 850 nanometers and 1300 nanometers.

4. Bandwidth:

Single-mode fiber: The bandwidth is theoretically unlimited because only one mode of light is allowed to pass through.

multi-mode fiber: Bandwidth is limited by the light mode and is usually lower than single-mode fiber.

5. Transmission distance:

Single-mode optical fiber: suitable for long-distance communications, capable of achieving transmission distances of tens to hundreds of kilometers.

Multimode optical fiber: suitable for short-distance communication, and the transmission distance is shorter than single-mode optical fiber.

6. Application:

Single-mode optical fiber: commonly used for long-distance communications, such as metropolitan area networks, wide area networks, optical fiber interconnections, etc.

Multimode optical fiber: often used for short-distance communications and local area network connections, such as office internal networks, data center internal connections, etc.

FCST - Better FTTx, Better Life.

We have been designing, manufacturing and supplying passive components for fiber optical networks since 2003. Everything we do in FCST is designed to provide efficient, simple and innovative solutions to solve complicated tasks.

We offer 4 solutions

lFTTH ODN Solution

lUnderground Cable Installation Solution

lAerial Cable Installation Solution

lFiber Tools & Test Solution

As a FTTx solution supplier, we can also do ODM according to project. We will continue to innovate and contribute more to the construction of the global optical fiber network.