LMA Fiber Mode Margin

Check large-mode-area fiber higher-order-mode suppression and fundamental transmission.

Description

Higher-order-mode suppression compares differential losses over a fiber length.

Higher-order-mode suppression compares differential losses over a fiber length. Fundamental transmission is calculated separately from its own loss.^[1]

Check large-mode-area fiber higher-order-mode suppression and fundamental transmission.

When to use LMA Fiber Mode Margin

Use this tool to check large-mode-area fiber higher-order-mode suppression and fundamental transmission.

Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.

How to use LMA Fiber Mode Margin and understand its results

Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
Enter fundamentalLossDbPerMeter, homLossDbPerMeter, deliveryLengthMeters, requiredHomSuppressionDb using the field table and calculation rules, then run the tool.
Read homSuppressionDb, suppressionMarginDb, fundamentalTransmissionPercent, meetsSuppression. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
fundamentalLossDbPerMeter	Fundamental-mode loss (dB/m)	number; minimum: 0	Required
homLossDbPerMeter	Higher-order-mode loss (dB/m)	number; minimum: 0	Required
deliveryLengthMeters	Delivery length (m)	number; minimum: 0	Required
requiredHomSuppressionDb	Required HOM suppression (dB)	number; minimum: 0	Required

Enter nonnegative dB/m losses, delivery meters and required dB suppression. Return suppression, margin, transmission and inclusive gate.

suppression=(HOMloss−fundamentalLoss)×length; transmission%=100×10^(−fundamentalLoss×length/10)

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
homSuppressionDb	Differential HOM suppression (dB)	number
suppressionMarginDb	Suppression margin (dB)	number
fundamentalTransmissionPercent	Fundamental transmission (%)	number; minimum: 0; maximum: 100
meetsSuppression	Meets suppression requirement	boolean

json

{
  "input": {
    "fundamentalLossDbPerMeter": 0,
    "homLossDbPerMeter": 2,
    "deliveryLengthMeters": 5,
    "requiredHomSuppressionDb": 8
  },
  "output": {
    "homSuppressionDb": 10,
    "suppressionMarginDb": 2,
    "fundamentalTransmissionPercent": 100,
    "meetsSuppression": true
  }
}

Limitations and assumptions

Suppression can be negative. No coupling between modes, bend profile or mode solver is included.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.

Alternative or Complementary methods

Use HOM Bend Suppression: Calculate bend-induced higher-order-mode suppression relative to the fundamental mode. For a complementary task, use Mode-Sorter Crosstalk: Calculate diagonal mode-sorting efficiency and off-diagonal crosstalk.

References

LMA Fiber Mode Margin — tool.io

Similar or alternative tools

HOM Bend Suppression
Calculate bend-induced higher-order-mode suppression relative to the fundamental mode.
Mode-Sorter Crosstalk
Calculate diagonal mode-sorting efficiency and off-diagonal crosstalk.