Overview
IEC TR 62627-04:2012 is a Technical Report in the IEC 62627 series titled Fibre optic interconnecting devices and passive components – Part 04: Example of uncertainty calculation: Measurement of the attenuation of an optical connector. It gives a worked example for estimating measurement uncertainty when measuring connector attenuation per IEC 61300-3-4 (attenuation of passive optical components), with particular focus on insertion method B for low-loss connectors assembled on single‑mode fibre (IEC 60793-2-50, Type B1.3).
This document is an example - not a replacement - for the general uncertainty guidance in ISO/IEC Guide 98-3:2008 (GUM). It shows the mathematical development of an uncertainty budget and compares uncertainty for measuring a full optical connection versus measuring one connector against a reference connector.
Key topics and technical requirements
- Measurement method: Insertion method B - uses a measurement plug (C1), a light source and a power meter to obtain reference power (Pin), then inserts the device under test (DUT, C2) and measures power (Pout).
- Attenuation calculation:
- Linear scale: A[dB] = −10 · log10(Pout / Pin)
- Log scale: A[dB] = Pin(dBm) − Pout(dBm)
- Measurement equipment: Light source types S4 or S5 (single‑mode sources at 1 310 nm or 1 550 nm) and a calibrated detector/power meter as defined in IEC 61300-3-4.
- Uncertainty analysis:
- Identification and quantification of principal uncertainty contributions (power meter, light source, DUT, reference connector/adaptor).
- Use of linear representation for calculations (results also presented in logarithmic units such as dB/dBm).
- Treatment of combined and expanded uncertainty, with worked examples and tabulated evaluations (see Annexes A and B).
- Assumption of uncorrelated quantities for this example, with guidance on when that is acceptable.
- Annexes:
- Annex A: brief introduction to measurement uncertainty per GUM.
- Annex B: full mathematical development of the uncertainty budget for attenuation measurements.
Practical applications and users
IEC TR 62627-04:2012 is valuable for:
- Test laboratories performing connector insertion loss measurements and reporting measurement uncertainty.
- Manufacturers and quality engineers validating connector performance and process control.
- Calibration and metrology personnel preparing uncertainty budgets for optical power/attenuation measurements.
- Standards developers and trainers needing an illustrative example of GUM application to fibre‑optic connector attenuation.
Related standards
- IEC 61300-3-4 (attenuation test methods for passive optical components)
- IEC 60793-2-50 (single‑mode fibre specifications, Type B1.3)
- IEC 61755 series (reference connector interfaces)
- ISO/IEC Guide 98-3:2008 (GUM - Guide to the expression of uncertainty in measurement)
Keywords: IEC TR 62627-04:2012, measurement of the attenuation of passive optical components (IEC 61300-3-4), insertion method B, optical connector attenuation, uncertainty calculation, single‑mode optical fibre, reference connector.