OptoTest Standards Cheat Sheet
Insertion Loss Measurement Procedures
FOTP-171
FOTP-171 was rewritten to include EF for all methods. It still includes overfilled launch conditions, and the mode filter launch conditions as alternatives.Method A: Single cable reference.
Method B: Two cable method, with a recommendation to measure multimode cabling in two directions by swapping the ends.
Method C: Replacement method (golden cable) for hybrid cable styles.
IEC 61300-3-4
Insertion Method A: Splice between loss. DUT is spliced between a length of fiber for the measurement.
Insertion Method B: Single reference cable method. DUT connected at end of reference cable for measurement.
Insertion Method C: Two reference cable method. Two reference cables referenced together and DUT connected between them for measurement.
Equipment Requirements
FOTP-171 Source Requirements:
Nothing specifically stated. Recommended mandrel sizes:
| Table 1 – Mandrel Mode Filter Sizes | |
| Fiber Core Diameter (microns) | Mode Filter Diameter (mm) |
| 50 | 25 |
| 62.5 | 20 |
| 100 | 25 |
Encircled Flux to be added in the future.
FOTP-171 OPM requirements:
Resolution: 0.05dB for loss >5dB, 0.01dB for loss <5dB.
IEC 61300-3-4
Source Requirements.
| Table 1 – Preferred source conditions | ||||
| No. | Type | Central wavelength nm |
Spectral width nm |
Source type |
| S1 | Multimode | 660 ± 30 | ≥30 | Monochromator or LED |
| S2 | Multimode | 780 ± 30 | ≥30 | Monochromator or LED |
| S3 | Multimode | 850 ± 30 | ≥30 | Monochromator or LED |
| S4 | Multimode | 1300 ± 30 | ≥30 | Monochromator or LED |
| S5 | Multimode | 1310 ± 30 | To be reported | Laser diode monochromator or LED |
| S6 | Multimode | 1550 ± 30 | To be reported | Laser diode monochromator or LED |
| S7 | Multimode | 1625 ± 30 | To be reported | Laser diode monochromator or LED |
Stability shall be +/-0.01dB for SM assemblies over the duration of the measurement. For MM assemblies +/-0.02dB.
Source output power needs to be 20dB above the minimum power level.
Source launch conditions: Encircled flux launch per IEC 61300-1 for
Optical Power Meter Requirements.
| Number | Type | Maximum nonlinearity dB | Relative uncertainty dB |
| D1 | Multimode | ± 0.05(-60dBm < input power < -5dBm) | ≤0.05 |
| D2 | Single Mode | ± 0.01(attenuation < 10dB)± 0.05(10dB < attenuation < 60dB) | ≤0.02 |
NOTE 1: In order to ensure that all light exiting the fibre is detected by the power meter, the sensitive area of the detector and the relative position between it and the fibre should be compatible with the numerical aperture of the fibre.
NOTE 2: Common sources of relative uncertainty are polarization dependence and interference with reflections from the power meter and fibre connector surfaces. The sensitivity of the power meter to such reflections can be characterized by the parameter spectra ripple, determined as the periodic change in responsivity vs. the wavelength of a coherent light source.
Return Loss
IEC 61300-3-6: Method 2, Return Loss measurement with OTDR.
Connector Loss/Geometry Specifications
FOTP-171
| Table A1 – Recommended Multimode Reference Connector Criteria | ||
| Parameter | Section | Reference Criteria |
| Ferrule outside diameter | A.2.1.1 | 2.4990 ± 0.0005mm |
| Connector endface geometry: Radius of curvature Apex offset Fiber height |
A.2.1.2 | 10 to 25mm 50 microns maximum ± 50nm |
| Polished ferrule length | A.2.1.3 | Per applicable FOCIS document requirement |
| Reference connector loss | A.2.1.4 | ≤ 0.25dB at 850 and 1300nm |
| Beam exit angle | A.2.1.6.5 | ≤ 0.5 degree |
| Fiber core position | A.2.1.6.4 | Eccentricity ≤ 3 microns |
A.2.2.1 Single Mode
The values in table A2 are recommended for the following Class IV single mode fiber types installed in non-angled physical contact connectors: 9.3/125, 1310/1550nm, 0.13 NA
| Table A2 – Recommended Single Mode Reference Connector Criteria | ||
| Parameter | Section | Reference Criteria |
| Ferrule outside diameter | A.2.1.1 | 2.4990 ± 0.0005mm |
| Connector endface geometry:Radius of curvature Apex offset Fiber height |
A.2.1.2 |
10 to 25mm |
| Polished ferrule length | A.2.1.3 | Per applicable FOCIS document requirement |
| Reference connector loss | A.2.1.4 | ≤ 0.15dB at 1310 and 1550nm |
| Beam exit angle | A.2.1.6.5 | ≤ 0.25 degree |
| Fiber core position | A.2.1.6.4 | Eccentricity ≤ 0.25 microns |
IEC
Connector Loss Grades
Insertion Loss get grades of A, B, C, etc.
| Table 2 – Single Mode attenuation grades at 1310nm and 1550nm (dB) | |||
| Attenuation grade | Attenuation (≥ 97%)* | Mean | Notes |
| A | Reserved for future application | ||
| B | ≤ 0.25 | ≤ 0.12 | |
| C | ≤ 0.50 | ≤ 0.25 | |
| D | ≤ 1.0 | ≤ 0.50 | |
* The probability of a random mated connector set of meeting or exceeding the specific level of attenuation will be ≥ 97%. This performance is reached considering a statistical distribution of connector’s parameters (MFD, eccentricity and tilt angle) and using a nominal value for wavelength.
Return Loss get grades of 1, 2, 3, etc.
| Table 3 – Single Mode Return Loss grades at 1310nm and 1550nm (dB) | ||
| Return Loss grade | Return Loss (mated) | Notes |
| 1 | ≥ 60 | ≥ 55dB in unmated condition (APC only) |
| 2 | ≥ 45 | |
| 3 | ≥ 35 | |
| 4 | ≥ 26 | |
Reference Grade Connectors
IEC 61755-2-4, 61755-2-5
| Table 1 – Single Mode attenuation grades at 1310nm | ||
| Reference grade** |
Attenuation** (dB) | Contribution to measurement uncertainty*** (dB) |
| R1 | ≤ 0.1 | ± 0.1 |
| R2 | ≤ 0.2 | ± 0.2 |
** Under the assumption of worst case alignment with identical connector plug. Expected attenuation measured when connecting two plugs of the same grade may be higher due to significant measurement uncertainty.
*** As described in Clause 8.