IEC 61300-3-5:2004 pdf download-Fibre optic interconnecting devices and passive components – Basic test and measurement procedures.
4 Apparatus 4.1 Device under test (DUT) The DUT has two optical ports. The ports may be terminated with pigtails or with connectors. Reference plugs with pigtails, and as required, reference adapters, shall be added to those ports with connector terminations so as to form complete connector assemblies with pigtails. 4.2 Detector (D) The detector consists of an optical detector, the associated electronics and means for connecting to an optical fibre. The optical connection may be a receptacle for an optical connector, a fibre pigtail or a bare fibre adapter. The detector shall be linear. Since all of the measurements are differential, however, it is not necessary that the calibration be absolute. Care should be taken to suppress the reflected power from the detector, D, during the measurement. Where, during the sequence of measurements, a detector is disconnected and reconnected, the coupling efficiency for the two measurements shall be maintained. Use of a large area detector to capture all of the light emanating from the fibre is recommended. 4.3 Variable wavelength source (VWS) The variable wavelength source is a light source which can select a specific output wavelength. The stability at the operating wavelength shall be better than ±0,05 dB over the measuring period. The variable wavelength source may consist of a broadband source (BBS) and an adjustable wavelength selective element, e.g. a wavelength tunable filter or fibre Bragg grating or a coherent wavelength-tunable source, etc. The centre wavelength shall be accurate enough to measure the wavelength dependency. The side mode suppression ratio (SMSR) of the variable wavelength source shall be high enough for the wavelength dependency of attenuation to be measured. The bandwidth of the adjustable wavelength selective element shall be narrow enough for the wavelength dependency of attenuation to be measured. Care must be taken to see that coherent interference effects are avoided.