Fiber Array Unit (FAU) & PMF

PMF FAU / Fiber Array Unit for CPO and Silicon Photonics

The BWNFiber PMF fiber array unit is a precision coupling assembly that aligns polarization-maintaining fibers to silicon photonic chips, optical engines and CPO interfaces. Channel count, pitch, substrate and slow-axis orientation are defined by the approved application drawing.

Verified Specifications

ParameterSpecification
Fiber typePanda-type PMF; elliptical-core PMF optional
Operating wavelength1310 nm / 1550 nm typical; custom wavelengths available
Channel count1×4, 1×8, 1×12, 1×16; custom on request
Fiber pitch127 µm standard; 250 µm or custom on request
Slow-axis alignment±3° standard; ±1° or tighter on request
Insertion loss≤0.50 dB typical per channel
Return loss≥55 dB typical
Extinction ratio≥20 dB typical
Substrate materialGlass V-groove or silicon V-groove
Fiber protrusionPer customer drawing; typically 0.3–1.0 mm
Operating temperature-20°C to +70°C standard; extended range available

Standard single-mode arrays, detachable FAU configurations and custom pigtail exits are project options until the exact drawing and datasheet are approved.

When to Use a PMF FAU

  • Silicon photonics chip coupling in optical engines
  • External laser source interface in CPO switch trays
  • CPO and NPO modules
  • Optical backplanes and board-to-board optical interconnects
  • High-density optical subassemblies for AI and HPC equipment

Use a PMF patch cord / pigtail instead when

The link only needs a connectorized polarization-preserving cable and does not require chip-level array coupling.

Use an optical flex circuit instead when

The equipment requires flexible routing, channel shuffling or multiple exits inside a constrained envelope.

Installation and Acceptance Checklist

  1. Provide the optical-engine or chip-coupling drawing.
  2. Define the slow-axis orientation and angular tolerance.
  3. Confirm protrusion, substrate outline and pigtail exit.
  4. Specify environmental qualification requirements.
  5. Agree on IL, RL, extinction-ratio and end-face limits.
  6. Handle only by the substrate or strain relief.

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Request a FAU Drawing

Send the optical-engine drawing, channel count, pitch, slow-axis orientation, protrusion, quantity and application details for review.

Request a FAU Drawing and Quote

FAQ

Frequently Asked Questions

What is a PMF FAU?

It is a fiber array unit built with polarization-maintaining fibers and controlled channel geometry.

What is V-groove alignment?

Precision grooves in a glass or silicon substrate hold each fiber at a fixed pitch.

Why does slow-axis orientation matter?

It aligns the maintained polarization axis with the polarization-sensitive photonic interface.

What is the standard fiber pitch?

127 µm is common; 250 µm and project-specific pitches can be reviewed.

Can the FAU be detachable?

Detachable configurations may be reviewed as a project option.

What channel counts are available?

Common configurations include 1×4, 1×8, 1×12 and 1×16, plus drawing-based custom arrays.

What test data is available?

IL, RL, end-face inspection, extinction-ratio and channel-map records can be specified.

How does a PMF FAU differ from an optical flex circuit?

A PMF FAU is a rigid pitch-controlled chip-coupling interface; a flex circuit supports complex flexible routing.

What drawing should I send?

Send fiber count, pitch, orientation, protrusion, substrate outline and environmental requirements.

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