Month: November 2018

Optical Fused Coupler: Advantages and How to Buy the One Best For You

A fiber optic coupler is a crucial part of most electric devices wherein signals need to be converted from input to output. Without couplers, those electric devices have no importance, they are useless. So it is vitally important to wisely choose a coupler as to achieve the desired result.

What Is An Optical Coupler?

An optical coupler is a sort of device used for coupling light from at least two input fibers into one output fibers. The coupler consists of an input section with an output end face at one end of the bundling-length of input fibers and an output section that has an output fiber to confine the region to confine the light propagated in the input fibers and a surrounding cladding region.

When it comes to coupling light or let’s say, converting input lights from different fibers to a single output fiber, optical fused coupler remains one of the best options.

Advantages of Fused Couplers

Fuse coupler has many advantages. And one is that the output section comprises an optical fiber which can be made in appropriate lengths and which can be easily tapered.  This means the component can be made into two separate functional units. And this is a great advantage with the optical fused couplers.

Some other crucial benefits that a fused coupler offers include:

  • Tapering of the input fiber bundle can be dispensed
  • Output fiber can be made on a fiber drawing tower in long lengths with excellent production reproducibility.
  • Tapering can either be done during fabrication of the output fiber or after its fabrication
  • Another benefit is that the light in the tapered output section will never reach a surface or an interface that can have contamination due to handling.
  • Output fiber (including the confining region and a surrounding cladding region) is tapered down.
  • Higher longevity.
  • And affordable

Besides, there are many other benefits that you will discover later.

Choosing an Optical Coupler

There are different types of couplers used for optic fibers. With different features, each of them is best used for a certain goal. So it is important to choose a coupler that is perfect for what you want it to do.

So first get to know what you want, and with what kind of electrical device you want to use it for.

Now, you should search for options available. There are manufacturers that make couplers for optical fibers. But it is advisable to go with the one who is widely renowned as well as affordable. So take the time and do a market research to know what the options are and what those options offer so you can make the right decision.

Optical Circulators and Their Applications

The ‘optocirculator’ commonly known as optical circulator is the circulator which is majorly used for optical communication. It is actually similar to the isolator but, optical Isolator is used to insert resistance to the reverse signal with loss of insertion whereas, optical circulator directs the light to one port and diverts it out to the non-reciprocal port. Isolator typically has 2 ports only while circulator has 3 to 4 ports.


Originally, polarization insensitive optical circulators were used in telecommunication systems in order to increase the capacity of transmission of existing networks. The Utilization of these circulators in a bi-directional transmission system can double the network’s transmission capacity without deploying extra fibers, earlier, this task was very expensive without optical circulators.

However, the uses of optical circulators have greatly expanded in not only the telecommunication sector but also the imaging and sensing industries with the quick and great advancement in optical communication technologies and the wide availability of high-performance circulators at lower costs. Optical circulators have now become a vital element in advanced optical networks.

Typical Specifications for Optical Circulator:

  • Grade type (P or A)
  • Number of Ports (3 or 4 ports)
  • Insertion loss (0.6/0.8) over +/- 20 nm bandwidth
  • Central Wavelength (1310nm or 1550nm)
  • Directivity (60 dB)
  • Power handling limit (300 mW)
  • Isolation (min.40dB)
  • Return Loss (60 dB)
  • PDL (0.1 dB)
  • WDL (0.2 dB)
  • PMD (0.1 ps)

Optical circulators are intensively powerful devices that are generally used to extract optical signals from a reflective device. In this manner, optical circulators are regularly utilized related to the fiber Bragg gratings that are ordinarily reflective devices. Together with fiber Bragg gratings, optical circulators have turned out to be one of the vital components in advanced DWDM optical systems. Circulators are utilized as MUX/DEMUX systems, but at the same time are utilized in dispersion compensation with the fiber Bragg grating, tunable optical Add/Drop, and other different applications.

The idea has been adapted into different devices, such as replacing the coupler and erbium-doped fiber with a dispersion compensation fiber to reduce the required fiber length and adding a Faraday rotator in-between the fiber and mirror in order to reduce the polarization-induced effects. Also, bi-directional fiber amplifiers are also proposed for taking full advantage of the polarization insensitive optical circulator.

With the improvement in advanced optical systems, the uses of optical circulators are extending quickly and new uses and applications are rising rapidly. For instance, as of late it has been accounted that by including wavelength-specific capacities into circulators, a bi-directional wavelength-subordinate circulator can be arranged, which opens another measurement of uses in the advanced DWDM optical systems.

These circulators are widely used for several other applications and this why they are extensively available at the stores as well as online. Due to increase in demand, there are thousands of manufacturers and millions of suppliers of optical circulators all around the world.