PM (Polarization Maintaining) filter coupler is the best solution for power monitoring systems and high optical performance and stability. It uses TFF (Thin-Film Filter) technology to enable the input signal to split into various ratios with polarization maintenance, high extinction ratio, and low insertion loss. This article will mainly introduce PM filter couplers.
What is a PM Filter Coupler?
PM filter coupler is a PM coupler that combines the light coming from the two input PM fibers into one output PM fiber or splits the light from the input PM fiber into two output PM fibers. It supports the light wave of each polarization to work without blocking any polarization. PM filter coupler is available with SMF-28e or Panda PM fiber types for tap, input, and output ports and without or with the connectors (FC/APC, FC/PC, SC/APC, SC/PC, LC/APC, LC/PC). The PM fiber and the connector key are aligned to the slow axis, and the fast axis is blocked.
What is the Role of the PM Filter Coupler in Power Monitoring?
The role of the PM filter coupler in power monitoring is to split high-power linearly polarized light into multiple paths without perturbing the line state of polarization (SOP). It can also be used as a power tap to monitor signal power in a PM fiber system without disturbing the linear SOP of light propagating in the PM fiber. The PM Filter Coupler is suitable for power sharing in polarization-sensitive systems and signal monitoring in PM fiber systems.
How is the Coupling Ratio in the PM Filter Coupler Determined?
The coupling ratio of signals or splitting proportions relies on the PM filter coupler configuration. A coupler ratio is the ratio in which input optical signals are divided between different outputs. For example, with a 50:50 coupling ratio in 1×2 PM filter couplers, the optical signals are divided in equal proportion in two output PM fibers. In such couplers, half of the input optical power is coupled to each port. Other common coupling ratios include 90:10, 80:20, and 70:30. With these coupling ratios, a PM filter coupler doesn’t couple equal power to both the output-PM ports. For example, in a PM filter coupling with an 80:20 coupling ratio, 80% percent of optical power is sent to one output PM fiber, and 20 % of the remaining optical power is directed to another output PM fiber.
Features and Benefits
PM filter coupler provides the following features and benefits:
1. Low insertion loss and polarization-dependent loss
2. Low back reflection, excess loss, and cost
3. High isolation and extinction ratio
4. High reliability and stability
5. High return loss and power handling
6. Epoxy-free optical path and compact size
7. Port configurations available 1×2, 2×2, 1×4, 2×3
8. Coupling ratios 50:50, 70:30, 75:25, 80:20, 90:10, or 99:1
9. Center wavelength available 780/850/980/1030/1064/1150/1310/1480/1550/1940/2000/2050nm
Applications
PM filter coupler is used in a fiber laser, fiber optic sensing, testing instruments, coherent optical transmission, fiber optic amplifiers, EDFA, CATV, R&D laboratories, fiber interferometers, power monitoring systems, etc.
Conclusion
PM filter coupler provides a high extinction ratio, isolation, stability and reliability, low insertion loss, and epoxy free in the optical path, making it the ideal choice for fiber optic amplifiers, fiber lasers, and testing instrument applications.
Sun Telecom specializes in providing one-stop total fiber optic solutions for all fiber optic application industries worldwide. Contact us if you have any needs.
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