PM FWDM Filter Wavelength Division Multiplexer

Product Description

The PM FWDM Filter Wavelength Division Multiplexer (WDM) is a specialized component designed for polarization-maintaining (PM) fiber systems, enabling the multiplexing and demultiplexing of multiple wavelength channels while preserving the input polarization state. Utilizing high-precision thin-film filters or polarization-insensitive AWGs, it supports coarse wavelength division multiplexing (CWDM) bands (e.g., 1270–1610 nm in 20 nm increments) with low polarization crosstalk and high channel isolation. The device features a compact form factor (≤40mm length) with PM fiber pigtails and FC/APC connectors, ensuring seamless integration into PM fiber links.

Features

Polarization Preservation: Maintains PER ≥25 dB and polarization-dependent loss (PDL) ≤0.3 dB across all channels, critical for polarization-sensitive applications.

High Channel Isolation: Adjacent channel isolation ≥30 dB, non-adjacent ≥40 dB, minimizing crosstalk between multiplexed wavelengths.

Wide Wavelength Coverage: Supports up to 18 CWDM channels (1270–1610 nm) and custom wavelength pairs (e.g., 1064 nm/1550 nm for laser-sensing systems).

Low Insertion Loss: ≤1.0 dB per channel for multiplexing/demultiplexing, with return loss ≥55 dB to reduce signal reflections.

Robust Design: Hermetically sealed housing with anti-vibration coatings, operating reliably from -40°C to 85°C.

Applications

Polarization-Maintaining Networks: Enables dense wavelength multiplexing in coherent optical transceivers for 5G and long-haul telecom systems.

Fiber Laser Systems: Combines multiple PM pump lasers (e.g., 976 nm, 1480 nm) with PM signal fibers in high-power, single-polarization laser sources.

Precision Sensing: Multiplexes signals from PM-based FBG sensors in structural health monitoring and aerospace applications.

Quantum Communication: Preserves polarization-entangled states in quantum key distribution (QKD) systems across multiple wavelength channels.

Medical Imaging: Enhances resolution in polarization-sensitive optical coherence tomography (OCT) by separating multiple spectral bands.

Faq

Q: Why is polarization maintenance important in FWDM?

A: In applications like coherent detection or quantum optics, preserving polarization ensures accurate signal reconstruction and state integrity.

Q: Can it be used with non-PM fibers?

A: Yes, but polarization-related performance (PER, PDL) will not be optimized; it is recommended for PM fiber systems.

Q: What is the maximum number of channels supported?

A: Standard models support up to 18 CWDM channels; custom designs for DWDM (40+ channels) are available with reduced channel spacing (0.8 nm).

Q: How is polarization crosstalk minimized?

A: Through precise alignment of PM fiber axes with the filter's polarization axis and low-ellipticity coatings on the filter surfaces.

Q: Does it require active alignment during installation?

A: No, the pre-terminated PM pigtails with polarization markers ensure easy and accurate passive alignment.