3 Port High Isolation FWDM

The FWDM (Filter Wavelength Division Multiplexer) is a passive optical device designed to combine or separate multiple wavelengths over a single fiber. The 3-port FWDM is widely used in FTTH, PON, and WDM systems to enable bidirectional transmission and increase network capacity.

ANFKOM provides high-performance FWDM modules with low insertion loss, high isolation, and excellent reliability, making them ideal for modern fiber optic networks.

What Is FWDM?

FWDM (Filter WDM) is a wavelength division multiplexing technology based on thin film filter (TFF) technology. It allows multiple optical signals at different wavelengths to be transmitted through a single fiber without interference.

Typically, FWDM operates with three wavelengths: 1310nm, 1490nm, and 1550nm, which are widely used in FTTH and PON systems.

👉 It works like a “smart optical filter,” combining and separating signals efficiently.

3-Port FWDM Structure (COM / Pass / Reflect)

A standard 3-port FWDM consists of:

• COM Port (Common) → shared fiber line
• Pass Port → transmits specific wavelength (e.g., 1490nm)
• Reflect Port → reflects other wavelengths (e.g., 1310nm & 1550nm)

This structure enables bidirectional communication on a single fiber, improving network efficiency and reducing infrastructure cost.

Key Features of 3 Port FWDM

• Low insertion loss (≤0.6 dB typical)
• High channel isolation (≥30 dB)
• Wide wavelength range (1260–1670nm)
• Based on stable TFF technology
• Compact size (steel tube / ABS box)
• High reliability in harsh environments (-40°C to +85°C)

How FWDM Works

FWDM uses thin film interference filters to selectively transmit or reflect different wavelengths.

• Incoming signals with multiple wavelengths
• Filter separates wavelengths based on optical properties
• Each wavelength is directed to the correct port

This allows simultaneous upstream and downstream transmission, increasing fiber capacity.

Applications of FWDM

FWDM modules are widely used in:

• FTTH / FTTx networks
• PON systems (GPON, EPON)
• CATV systems
• Optical amplifiers (EDFA)
• WDM communication networks

They are essential for combining upstream and downstream signals in a single fiber link.

How to Choose the Right FWDM

1. Wavelength Requirement

• Standard: 1310 / 1490 / 1550nm
• Custom wavelengths available

2. Application

• FTTH → standard FWDM
• CATV → require video wavelength support

3. Package Type

• Steel tube → compact installation
• ABS box → easier handling

FAQ

What does FWDM stand for?

FWDM stands for Filter Wavelength Division Multiplexer.

What is FWDM used for?

It is used to combine or separate multiple wavelengths in fiber optic networks, especially in FTTH and PON systems.

What is the difference between FWDM and CWDM?

FWDM handles fewer wavelengths (typically 3) and is more cost-effective for access networks.

Specification

The above specification is for devices without connectors.