All About Various Optical Attenuator (EDFA, FRA, and SOA)

Optical Amplifier

The transmission loss of the light that passes through optical switch fiber is the very small value of less than 0.2 dB per km with a light wavelength in the 1,550 nm band.

An optical amplifier is an extremely important device that supports the long-distance optical communication networks of today and it amplifies light as it is without converting the optical signal to an electrical signal. The main type of optical amplifiers includes an EDFA(Erbium-Doped Fiber Amplifier), FRA(Fiber Raman Amplifier), and SOA(Semiconductor Optical Amplifier).

FRA (Fiber Raman Amplifier)

An FRA is a type of OFA. When strong excitation light enters the optical attenuator fiber it causes stimulated emission based on SRS. In a wavelength range about 100 nm longer than the excitation light wavelength, the light is then amplified. It has a wide amplification wavelength region, and it can be freely set by the wavelength of the excitation light.

DFA (Erbium-Doped Fiber Amplifier)

An EDFA is 1 type of OFA and is an optical amplifier that consists of erbium ions added to the core of the optical fiber. It can amplify optical signals in the 1.55 μm band or 1.58 μm bands, features high gain and low noise, and is polarization independent.

Previously it was important to use an optical repeater to temporarily convert attenuated light into an electrical signal, then electrically amplify it and regenerate the waveform, then convert back to light and resend it.

SOA (Semiconductor Optical Amplifier)

An SOA is a semiconductor element. On the cleavage plane of a semiconductor laser by performing antireflective processing and eliminating the resonator structure, light can easily enter from outside the semiconductor and amplify light via stimulated emission.

In a compact size, you can make an SOA, and compared to an EDFA its lower running costs mean it is more economically efficient. Till recent years, the input light of an SOA was highly polarization-dependent but in recent years research into low polarization, dependency has proceeded. Furthermore, at data centers, optical amplifier EDFA is being replaced by SOAs, and their use is expected to expand in future optical communication.

FBT and PLC Fiber Optic Splitters Differences

To share the optic network with multiple users, fiber splitter is an important component in PON and FTTx architectures. Splitting one optic light beam into several parts at a certain ratio is the basic principle of fiber optic splitter. Fiber optic splitters can be divided into FBT and PLC splitters as per different manufacturing technologies. When choosing between them, you may wonder about the differences between the two splitter types.

FBT & PLC Splitters Differences 

PLC and FBT splitters still have many differences although they may look similar to each other when it comes to actual applications. Here we are going to compare them from several other aspects.

Wavelength Range

Ranging from 1260 nm to 1620 nm, the PLC splitter has a wider operating wavelength. Thus to most of the applications in PON and FTTx networks, it can be applied. Only to be used for 1550nm, 1310nm, and 850nm wavelengths, and FBT splitter has a limitation on the contrary.

Splitting Ratio

By the outputs and inputs of a splitter, the Splitting ratio is decided. With the splitting ratio of 1:64, A PLC splitter is available which means into 64 splits, one light beam can be separated at a time. However, for networks requiring the splitter configuration of fewer than 4 splits, and FBT splitter is used typically. It will cause a higher failure rate and more errors will occur when its splitting ratio is larger than 1:8. Thus to the number of splits in one coupling, the FBT splitter is more restricted. The fiber coupler is also useful.

Price

Its cost is generally higher than the FBT type Owing to the complicated manufacturing technology of the PLC splitter. FBT splitter is a cost-effective solution if your application is short of funds and simple.

Temperature-Dependent Loss

By the sensitivity of the device and manufacturing process, Temperature-dependent loss (TDL) of the splitter is affected. Insertion loss will influence the performance of the fiber splitter and increase once the working temperature of the splitter is out of range. At the temperature of -40 to 85 Celsius degrees, the PLC splitter can work while at -5 to 75 Celsius degrees, the FBT splitter can only work.