Ring Isolation Ratio

Calculate forward/reverse isolation in a unidirectional ring cavity.

Description

Isolation compares forward with reverse optical power.

Isolation compares forward with reverse optical power. A dB ratio represents a power ratio using ten times the base-ten logarithm.^[1]

Calculate forward/reverse isolation in a unidirectional ring cavity.

When to use Ring Isolation Ratio

Use this tool to calculate forward/reverse isolation in a unidirectional ring cavity.

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 Ring Isolation Ratio 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 forwardPowerWatts, reversePowerWatts using the field table and calculation rules, then run the tool.
Read isolationRatio, isolationDecibels, reverseFraction. 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
forwardPowerWatts	Forward circulating power (W)	number; minimum: 0	Required
reversePowerWatts	Reverse circulating power (W)	number; minimum: 0	Required

Enter nonnegative forward and positive reverse power. Use positive forward power for a finite dB output. Return ratio, isolation dB and reverse share.

ratio=forward/reverse; dB=10log10(ratio); reverseFraction=reverse/(forward+reverse)

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

Output field	Meaning	Value type
isolationRatio	Forward-to-reverse power ratio	number; minimum: 0
isolationDecibels	Ring isolation (dB)	number
reverseFraction	Reverse power fraction	number; minimum: 0; maximum: 1

json

{
  "input": {
    "forwardPowerWatts": 100,
    "reversePowerWatts": 1
  },
  "output": {
    "isolationRatio": 100,
    "isolationDecibels": 20,
    "reverseFraction": 0.009900990099009901
  }
}

Limitations and assumptions

Zero forward generates negative infinity and fails the output contract. No spectral, polarization or cavity-dynamics model is supplied.

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 Waveguide Joint Loss: Calculate cumulative hollow-waveguide joint loss and transmission. For a complementary task, use SCOWA Amplifier Output: Estimate SCOWA output from small-signal gain and a supplied saturation ceiling.

References

Ring Isolation Ratio — tool.io

Similar or alternative tools

Waveguide Joint Loss
Calculate cumulative hollow-waveguide joint loss and transmission.
SCOWA Amplifier Output
Estimate SCOWA output from small-signal gain and a supplied saturation ceiling.