1x2 2x2 Fused PM Fiber Optic Coupler Polarization Maintaining Coupler 1310nm 1550nm

Product Overview: The 1*2 / 2*2 Fused PM Fiber Coupler is a standard polarization-maintaining fiber coupler manufactured using fused biconical taper (FBT) technology. It offers 1*2 and 2*2 port configurations, suitable for achieving stable power distribution or combining under the same polarization state. The standard operating wavelengths are 1310 nm and 1550 nm, with custom wavelengths of 980 nm, 1064 nm, and 780 nm supported, covering commonly used communication and laser bands. The device uses Panda PM13-U25A polarization-maintaining fiber, with a default fiber length of 1.0±0.1 m. Optional configurations include 250 μm bare fiber, 0.9 mm loose tube, and 2.0/3.0 mm sheathed structures. It is compatible with various connectors such as FC/UPC, FC/APC, SC, and LC. The default connector keypad is aligned to the slow axis, and a "slow axis only" or "fast axis application" mode can be selected, providing a flexible optical path foundation for polarization-sensitive systems.

Product Applications: At the application level, this fused polarization-maintaining coupler is primarily designed for various polarization-dependent fiber optic systems. For EDFA fiber amplifiers, it can serve as an input or output power divider, diverting a portion of the signal light for monitoring or cascaded amplification. In fiber optic instruments, it can function as an internal fixed beam splitter for building optical paths for interferometry, coherent detection, and polarization-dependent measurements. In coherent communication systems, it can distribute the input signal to the local oscillator and monitoring branches according to a specific splitting ratio, providing an optical power foundation for coherent reception and performance monitoring. In power monitoring and fiber optic sensing systems, it can divert a small proportion of the main link signal for online power detection or sensor probe excitation, thus achieving real-time status monitoring without significantly affecting the main channel power.

Product Features: This product is designed to balance low insertion loss, high extinction ratio, high return loss, and high directivity. At standard 1130/1550 nm operating wavelengths, the typical excess loss does not exceed 0.8 dB. The overall insertion loss has strict upper limits for different splitting ratios: for example, 50/50 splitting ratio P-class insertion loss ≤3.6 dB, A-class ≤3.8 dB; 20/80 splitting ratio P-class ≤7.8/1.6 dB, and other ratios such as 10/90, 5/95, and 1/99 also have clearly defined IL upper limits for easy link budgeting. The polarization extinction ratio is ≥18 dB, ensuring good selectivity for polarization states in polarization-maintaining links; the return loss is ≥50 dB, and the directivity is ≥55 dB, effectively suppressing the impact of reflections and crosstalk signals on the pre-stage laser, amplifier, or precision detection unit. Maximum optical power handling capacity ≤0.5 W, operating temperature range -5～+65 ℃, storage temperature -40～+80 ℃, meeting the long-term stable operation requirements of communication equipment rooms and most experimental environments.

Product Applications: From a system integration perspective, the 1*2 / 2*2 Fused PM Fiber Coupler is ideally suited as a polarization-maintaining power distribution and combining node within modules or between devices. In overall or sub-module designs, engineers can choose different packages depending on space and cabling conditions: 250 μm bare fiber corresponds to φ3.0*45 mm steel tubing, 0.9 mm loose sleeve corresponds to φ3.0*54 mm, while 2.0/3.0 mm patch cords use a 90*20*10 mm box package for easy mounting on chassis or test platforms. By flexibly configuring the splitting ratio (50/50, 20/80, 10/90, 5/95, 1/99, etc.), suitable power allocation schemes can be provided for different business scenarios: for example, 50/50 is used for dual-path equal power output, and 10/90 or 1/99 is used for online monitoring branches; the 1*2 type is suitable for single-signal splitting, while the 2*2 type can be used for bidirectional links or coupled/disconnected combined structures. With customizable fiber lengths and connector types, the device can be directly integrated into 1U/2U chassis, experimental optical circuit boards, or OEM modules, achieving a "plug-and-play" polarization-maintaining interface.

Product Advantages: Compared with ordinary single-mode fused couplers, the advantages of the Fused PM Fiber Coupler are mainly reflected in polarization maintenance capability, parameter controllability, and scheme flexibility. It utilizes Panda polarization-maintaining fiber and defaults to aligning the connector keyways with the slow axis, allowing engineers to clearly identify and maintain a consistent polarization direction during splicing, cabling, and field installation. This significantly reduces the impact of random polarization drift on system power, phase, and measurement results. The product offers both P-grade and A-grade specifications, facilitating differentiated choices based on insertion loss, cost, and performance. Multiple operating wavelengths and splitting ratio options allow the same series to cover diverse needs from communication systems and laser systems to sensing systems, reducing model fragmentation. The specification also clearly defines the upper limits of insertion loss, extinction ratio, return loss, and temperature range for each splitting ratio, and provides detailed ordering codes (fields such as number of ports, wavelength, splitting ratio, package type, fiber sheath, length, and connectors), greatly reducing the complexity of solution design, selection, and subsequent maintenance.

Summary: Overall, the 1*2 / 2*2 Fused PM Fiber Coupler is a high-performance polarization-maintaining coupling device designed for polarization-sensitive applications such as EDFA, fiber optic instruments, coherent communication, power monitoring, and fiber optic sensing. Through fused tapered bonding technology + Panda polarization-maintaining fiber + various splitting ratios and packaging combinations, it achieves a good balance between low insertion loss, high extinction ratio, high return loss, and high directivity, enabling flexible optical power distribution and combining while ensuring polarization stability. Whether used as a fixed functional module in mass-production equipment or as a reconfigurable optical path node on experimental platforms, this product helps users significantly improve system polarization stability, link reliability, and test repeatability, making it one of the essential foundational components for building high-quality polarization-maintaining fiber solutions.