The difference between special optical fiber and ordinary optical fiber

Next, we will explain the difference between widely used specialty fibers and standard communication fibers, as well as special problems encountered in the drawing process and more background knowledge.

Communication systems often include specialty optical fibers

Fiber optic technology has revolutionized the communications industry. Deployed for decades, fiber optic networks carry telephone, television and Internet services to end users and homes. These services are ubiquitous and heavily used. For example, in 2018, the average adult spent 8.5 hours of screen time per day on a smartphone, TV, tablet or PC. With the pandemic, the average daily usage time for adults has increased by more than 50% in 2020, to 13.5 hours per day.

Increased usage includes more video conferencing and other video services that require more network capacity than Web and audio communications. Fiber optic networks typically handle higher loads with minimal disruption. In some cases, network operators increase network capacity by lighting more fibers, adding more wavelength channels, or increasing bit rates. This illustrates the enormous capacity and flexibility of today's fiber optic networks.

Since the 1980s, the capacity of fiber optic systems has increased dramatically—characterized by bandwidth and distance. In the early days, the bandwidth of fiber optic systems was greater than that of copper cables, but it was far from meeting today's requirements. Distance performance is limited by the loss of light in the fiber, so a repeater station is required every 100 kilometers or so to receive the light signal, clean it up electronically, and then retransmit it.

All that changed with the development and use of specialty optical fibers to make optical amplifiers. The dopant provides optical gain in the wavelength band near the 1.55 µm low-loss port of the communication fiber. Fiber amplifiers boost transmission signals without the need for cleaning, regeneration time and regeneration repeaters. In addition, a single fiber amplifier can amplify multiple wavelength channels in the same fiber without crosstalk, thus greatly increasing the bandwidth of fiber optic systems. In this case, dedicated optical fiber supplements the use of communication optical fiber, thereby significantly improving bandwidth and distance performance.

What is the difference between special optical fiber and communication optical fiber

Specialty fibers can be defined as those that do not conform to standards for single-mode and multimode communication fibers. For single mode, the International Telecommunication Union standard is widely adopted. For multimode, the Fiber Optic Technology Alliance standard of the Telecommunications Industry Association is widely adopted. These multimode fiber specifications are also standardized by the International Electrotechnical Commission of the International Organization for Standardization.

In both cases, widespread adoption refers to fiber optic specifications used by fiber optic manufacturers and companies that make transceiver assemblies, fiber optic connectors, and other products that interface with fiber optics. Additionally, these fiber optic standards are used in standards for local area networks, telecommunications systems, and other infrastructure. Optical fiber standards specify geometric, physical and optical properties.

Communication fibers are designed to transmit modulated optical signals at specific wavelengths. Fiber designs are optimized for low loss and modal characteristics to support distance and bandwidth requirements. Specialty fibers are optimized for applications beyond signal transmission such as amplifiers, sensors, lasers, filters, ring resonators, and more. To meet these diverse applications, there are hundreds of different specialty fiber types, glass compositions, core and cladding structures, geometries, coatings and specially tailored optical performance characteristics. Some major specialty fibers have the following characteristics:

1. Special doping in the glass, especially the core;

2. The structure that causes the birefringence of polarization-maintaining fiber;

3. Multiple cladding;

4. Special refractive index distribution, adjusting waveguide characteristics such as emission characteristics, numerical aperture, effective area, and mode propagation;

Various combinations of these functions.

Many special fiber types are designed for sensing systems. Optical fiber-based sensors can measure a large number of chemical, physical, environmental and biological parameters. The breadth of sensing applications is a key reason for the wide variety of specialty fibers.