Tap couplers, also known as beam splitters, are commonly used optical devices that are designed to split a single light beam into two different transmitted and reflected beams.
This device can reflect a specific percentage of an input beam, also called incidence light, over a broad wavelength with a specific angle of incidence. It is a widely used device for monitoring optical fiber traffic in telecom and other similar applications.
What makes PM tap couplers special?
It is important to note that while regular tap couplers are readily available in the market, special attention needs to be paid when ordering polarization-maintaining tap couplers.
A polarization-maintaining (PM) tap coupler is designed specifically to split the light coming from the input polarization-maintaining fiber and transmit the two light beams through two output PM fibers.
Conversely, a non-PM tap coupler is designed to work with normal, non-polarized light and fibers.
Does Quality of PM Tap Couplers Matter?
High-quality PM tap couplers, like those manufactured by DK Photonics, are designed with separate light crystals, which results in a more accurate coupling ratio and the ability to handle higher power than PM-filter couplers.
PM tap couplers can be used to split a polarized beam into different paths without disturbing the state of polarization, and as a power tap to monitor signal power in a polarization-maintaining fiber system without affecting the linear SOP.
They are also useful in applications such as PM fiber interferometers and power-sharing in polarization-sensitive systems.
How to find the best PM tap couplers?
When selecting a tap coupler beam splitter, it is important to consider certain key characteristics.
Flatness, which is measured in percentage, refers to the maximum variation that occurs during transmission or reflecting beam over the range of wavelength. The fewer the variations, the better the quality of the tap coupler.
Polarization-dependent loss (PDL) is represented by dB and refers to the maximum change found in transmittance or reflectance at a given wavelength when the light travels through all possible polarization states.
The substrate etalon ripple effect, also represented by dB, can vary depending on the reflectance of the two sides of the filter and the parallelism of the substrate. This effect can be reduced to a minimum by creating a sufficient wedge angle or by forming a quality AR coating on the secondary surface.
Custom polarization-maintaining tap couplers can also be designed with different wavelengths, tap ratios, and handling power of operation. When selecting an ideal PM tap coupler, it is important to focus on its features that determine its quality, such as low insertion loss and high extinction ratio, isolation, and stability.
In summary, tap coupler beam splitters are important optical devices that are widely used for monitoring optical fiber traffic in various applications. Polarization-maintaining tap couplers are specifically designed to work with polarization-maintaining fibers and can be used in applications such as PM fiber interferometers and power-sharing in polarization-sensitive systems.
When selecting a tap coupler, it is important to consider certain key characteristics such as flatness, polarization-dependent loss, and the substrate etalon ripple effect. Custom PM tap couplers can be designed with different specifications to suit specific needs. Contact DK Photonics to order polarization-maintaining tap couplers now.