HOM Bend Suppression

Calculate bend-induced higher-order-mode suppression relative to the fundamental mode.

Description

Bend-induced mode suppression uses differential loss between higher-order and fundamental modes.

Bend-induced mode suppression uses differential loss between higher-order and fundamental modes. The initial ratio is scaled by that loss difference.^[1]

Calculate bend-induced higher-order-mode suppression relative to the fundamental mode.

When to use HOM Bend Suppression

Use this tool to calculate bend-induced higher-order-mode suppression relative to the fundamental mode.

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 HOM Bend Suppression 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 fundamentalBendLossDbPerMeter, homBendLossDbPerMeter, bentLengthMeters, initialHomToFundamentalRatio using the field table and calculation rules, then run the tool.
Read differentialSuppressionDb, outputHomToFundamentalRatio, fundamentalTransmissionFraction. 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
fundamentalBendLossDbPerMeter	Fundamental-mode bend loss (dB/m)	number; minimum: 0	Required
homBendLossDbPerMeter	HOM bend loss (dB/m)	number; minimum: 0	Required
bentLengthMeters	Bent fiber length (m)	number; minimum: 0	Required
initialHomToFundamentalRatio	Initial HOM/fundamental power ratio	number; minimum: 0	Required

Enter nonnegative loss rates, length and initial ratio. Return differential dB, output ratio and fundamental power transmission.

suppression=(HOMloss−fundamentalLoss)×length; outputRatio=initial×10^(−suppression/10)

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

Output field	Meaning	Value type
differentialSuppressionDb	Differential HOM suppression (dB)	number
outputHomToFundamentalRatio	Output HOM/fundamental ratio	number; minimum: 0
fundamentalTransmissionFraction	Fundamental transmission	number; minimum: 0; maximum: 1

json

{
  "input": {
    "fundamentalBendLossDbPerMeter": 1,
    "homBendLossDbPerMeter": 11,
    "bentLengthMeters": 1,
    "initialHomToFundamentalRatio": 1
  },
  "output": {
    "differentialSuppressionDb": 10,
    "outputHomToFundamentalRatio": 0.1,
    "fundamentalTransmissionFraction": 0.7943282347242815
  }
}

Limitations and assumptions

Higher-order loss below fundamental loss gives negative suppression and increased relative HOM content. No bend geometry or mode coupling is modeled.

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.

Alternative or Complementary methods

Use LMA Fiber Mode Margin: Check large-mode-area fiber higher-order-mode suppression and fundamental transmission. For a complementary task, use Mode-Sorter Crosstalk: Calculate diagonal mode-sorting efficiency and off-diagonal crosstalk.

References

HOM Bend Suppression — tool.io

Similar or alternative tools

LMA Fiber Mode Margin
Check large-mode-area fiber higher-order-mode suppression and fundamental transmission.
Mode-Sorter Crosstalk
Calculate diagonal mode-sorting efficiency and off-diagonal crosstalk.