850nm 2x2 Fiber Optic Coupler 50/50 Polarization Maintaining Fiber Coupler Dual Axis Working

850nm 2x2 PM Filter Coupler 50 50 Polarization Maintaining Fiber Coupler Dual Axis Working For Fiber Sensing Coherent Detection And Optical Instrument

Product Overview

The 850nm 2*2 PM Filter Coupler is a polarization-maintaining filter fiber coupler operating in the 850nm band. It employs a 2*2 port structure, enabling power distribution and combining of two optical signals while maintaining polarization characteristics. The device's operating center wavelength is 850nm, its operating bandwidth is ±20nm, and its standard splitting ratio is 50/50. It is suitable for near-infrared light source systems such as 850nm laser diodes and VCSELs. The product uses PM780-HP polarization-maintaining fiber (0.9mm loose tube), with a standard pigtail length of 1.0±0.05m. The package is a Φ5.5*L38mm stainless steel tube, and it is equipped with an FC/UPC connector. The device is compact, has high mechanical strength, and is easy to integrate into modules and perform field cabling. It supports Dual Axis working, allowing it to be used as a polarization-maintaining device in polarization-sensitive systems and also meeting the requirements of some dual-polarization applications.

At the application level, this 850nm 2*2 PM Filter Coupler is primarily designed for various near-infrared polarization-dependent systems. In EDFA or other fiber optic amplification front-end/back-end, it can be used for signal splitting, power sampling, or cascaded optical path construction. In various fiber optic instruments, it is often used as an internal fixed splitter/combiner unit, providing stable power distribution for interferometry, coherent detection, and precision measurement optical paths. In coherent communication and high-speed short-distance optical interconnects, it can distribute the same 850nm signal 50/50 to different receiving branches or local oscillator branches. In power monitoring and fiber optic sensing systems, it can split or combine return signals from different sensor probes from the main service link, enabling online monitoring and multi-point detection, making it a very practical basic coupling device in 850nm band systems.

In terms of performance, this PM Filter Coupler features low insertion loss, high extinction ratio, and good environmental adaptability. When operating within an 850nm±20nm bandwidth, the typical insertion loss is ≤4.3dB, making it suitable for systems sensitive to link power budgets. Its extinction ratio is ≥20dB when the coupling ratio is greater than 5%, and no less than 18dB even with a smaller coupling ratio (≤5%), effectively suppressing unwanted polarization components and improving the stability of polarization-dependent measurements and coherent detection. The return loss is ≥45dB, significantly reducing the impact of end-face reflections on the light source and pre-amplifier devices. The maximum optical power handling capacity is ≤500mW, meeting the needs of most low-to-medium power 850nm laser and testing systems. The device operates within a temperature range of -5 to +70℃, with a storage temperature range of -40 to +80℃, and a tensile strength of ≤5N. It can achieve long-term stable and reliable operation in conventional computer rooms, laboratories, and portable devices.

From a system integration perspective, the 850nm 2*2 PM Filter Coupler is well-suited for use as a core distribution node within modules or chassis-level optical paths. In overall system design, it can be placed after the light source or amplification stage, distributing one 850nm optical signal proportionally to two channels: one as the primary output and the other as a monitoring, calibration, or redundant link. In board-level systems, its 2*2 structure can be used to achieve "bidirectional coupling/disengagement" for constructing simple ring topologies or bidirectional transmission structures. On experimental platforms, its two-input, two-output port structure can flexibly build interferometric optical paths, phase noise testing links, or multi-detector power balancing systems. With different sheaths (0.9mm standard, also available in 250μm, 2.0mm, and 3.0mm) and various connector combinations, engineers can choose the most suitable integration method based on equipment space, cabling methods, and maintenance needs, reducing on-site construction difficulty.

Compared to ordinary single-mode 2*2 fiber optic couplers, this 850nm PM Filter Coupler's advantages are concentrated in three aspects: controllable polarization characteristics, well-defined parameters, and high flexibility in solution design. First, it utilizes PM780-HP polarization-maintaining fiber and supports biaxial operation, making it suitable for applications requiring polarization maintenance as well as systems that do not strictly limit polarization but desire stable coupling performance. Second, the datasheet provides clear specifications for key parameters such as insertion loss, extinction ratio, return loss, power handling capacity, and temperature range, facilitating link budgeting and performance simulation by system designers. Third, through standardized ordering codes, users can customize various dimensions, including port type (2*2), operating wavelength (850nm), splitting ratio (50/50), packaging (steel tube or box), fiber sheath, pigtail length, and connector type. This allows the same product series to cover multiple application levels, from laboratory verification to mass production, reducing model fragmentation and spare parts pressure.

In summary, the 850nm 2*2 PM Filter Coupler is a key polarization-maintaining coupling device for EDFA front-end/back-end, fiber optic test instruments, coherent communication, power monitoring, and fiber optic sensing. It provides stable 50/50 power splitting in the 850nm band, while also featuring low insertion loss, high extinction ratio, good return loss, and reliable environmental adaptability. It offers flexible and robust power splitting and combining capabilities for various optical path topologies within limited space. For equipment manufacturers and integrators looking to build highly stable, multi-channel, polarization-controllable systems in the 850nm band, this product is not only a fundamental passive device but also a key component for improving overall system performance and maintainability.