The 1*2 TFF Filter PM Fiber Coupler 30:70 is a polarization-maintaining fiber standard coupler based on thin-film filtering (TFF) technology. Operating in the 1550nm±40nm wavelength band, it splits one input light into two outputs at a 30%:70% ratio while maintaining polarization characteristics. The device uses Corning panda-type polarization-maintaining fiber, typically characterized by low insertion loss, high extinction ratio, and high return loss. It is suitable for "main service link + monitoring/branch link" structures and is a fundamental optical splitting device in polarization-sensitive systems such as EDFA, fiber optic instrumentation, coherent communication, and power monitoring.

• Designed specifically for 30/70 splitting, accommodating both main and monitoring branches

  Within a bandwidth of 1550nm±40nm, the maximum insertion loss for 30/70 splitting is ≤5.8 dB / ≤2.0 dB, ensuring sufficient power for the main link while reserving stable optical energy for monitoring or branch channels. Suitable for applications such as amplifier monitoring ports and backup channels.

• High extinction ratio, controllable polarization state

  The device has an extinction ratio of ≥20 dB, using panda-type polarization-maintaining fiber. The specification states that PM fiber and connector keying are aligned with the slow axis, while the fast axis is blocked, maintaining a stable polarization direction in the system, reducing polarization-dependent power fluctuations and coherent noise. It is highly compatible with polarization-sensitive EDFA, coherent receivers, and sensing systems.

• High Return Loss and High Directivity

  Return loss ≥50 dB effectively suppresses the impact of end-face reflections on the pre-stage laser, amplifier, and precision detector. Combined with the high directivity provided by the filter structure, it helps reduce crosstalk between ports, improving overall stability and signal-to-noise ratio.

• Good Power Handling and Environmental Adaptability

  Maximum optical power handling capacity ≤500 mW, operating temperature range -10～+65 ℃, storage temperature -40～+85 ℃, meeting the long-term online operation requirements of computer rooms, laboratories, and most engineering environments.

• Serialized Platform, Flexible Selection

  The same specification sheet provides insertion loss parameters for various splitting ratios such as 50/50, 20/80, 10/90, 5/95, and 1/99, facilitating the expansion of different product models on the same platform. OEMs can flexibly balance the "splitting ratio – insertion loss – monitoring requirements" according to different projects.

• Package Dimensions
  • 250 μm Bare Fiber Version: Steel Tube Package φ5.5 * 38 mm
  • 0.9 mm Loose Tube Version: Steel Tube Package φ5.5 * 38 mm
  • 2.0 / 3.0 mm Sheath Version: Cartridge Package 90 * 20 * 10 mm

  Suitable for compact integration within modules or standard tray mounting within chassis.

• Fiber Optic Fiber and Pigtail
  • Fiber Type: Corning Panda Polarization-Maintaining Fiber
  • Standard Pigtail Length: 1.0 ±0.1 m, other lengths can be customized upon request.
  • Sheath Type: 250 μm bare fiber, 0.9 mm blue loose tube, 2.0 mm / 3.0 mm sheath optional.
• Connector Configuration
  • Standard Connectors: FC/APC, FC/UPC, SC/UPC, SC/APC, LC/UPC, LC/APC, etc. can also be provided upon request.
  • Specifications indicate that the performance indicators given are for version with connector; PM fiber and connector key alignment is on the slow axis for easy on-site key alignment to unify polarization direction.
• Ordering Code Example

  Model Example PMC-1215530ST20910-22(S): Indicates a 1*2 Filter PM Fiber Coupler, 1550 nm, 30/70 splitter, φ5.5*38 mm steel tube package, 0.9 mm blue loose tube, 1 m pigtail, dual-ended FC/APC connectors, key alignment slow axis, S-grade precision.

• EDFA / Fiber Amplifier (Main Link + Monitoring/Sampling Port)
• Fiber Optic Instrument
• Coherent Communication
• Power Monitoring
• Fiber Sensor