IEC 61300-3-5:2000 pdf free download – Fibre optic interconnecting devicesand passive components – Basic test and measurement procedures
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 thoseports with connector terminations so as to form complete connector assemblies with pigtails.
4.2Detector (D)
The detector consists of an optical detector，the associated electronics and means forconnecting to an optical fibre. The optical connection may be a receptacle for an opticalconnector, a fibre pigtail or a bare fibre adapter.
The detector shall be linear. Since all of the measurements are differential, however, it is notnecessary that the calibration be absolute.Care should be taken to suppress the reflectedpower 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 areadetector to capture all of the light emanating from the fibre is recommended.
4.3Variable wavelength source (vws)
The variable wavelength source is a light source which can select a specific outputwavelength.The stability at the operating wavelength shall be better than ±0,05 dB over themeasuring 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 fibreBragg grating or a coherent wavelength-tunable source，etc. The centre wavelength shall beaccurate enough to measure the wavelength dependency.The side mode suppression ratio(SMSR) of the variable wavelength source shall be high enough for the wavelengthdependency of attenuation to be measured. The bandwidth of the adjustable wavelengthseiective element shall be narrow enough for the wavelength dependency of attenuation to bemeasured.
Care must be taken to see that coherent interference effects are avoided.
Unless otherwise specified，launch conditions shall be in accordance with Annex B ofIEC61300-1.
4.4Broadband source (BBS)
The broadband source is a light source which has enough output power in the chosenwavelength band.The broadband source may be a LED or an amplified spontaneous emissionof an optical fibre amplifier. lts output power shall be stable.The wavelength bandwidth shallbe wide enough for the wavelength dependency of attenuation to be measured.The stabilityof optical output power shall be better than ±0,05 dB over the measuring period.
4.5Optical spectrum analyser (OSA)
The optical spectrum analyser measures the output optical power at every wavelength overthe specified wavelength’ range. The optical spectrum analyser typically consists of adiffraction grating, an optical detector， associated electronics and an optical connector. Thewavelength resolution can be variable but shall be specified.The polarization sensitivity shallbe less than one-tenth of the wavelength dependency of attenuation to be measured.
5.2Optical spectrum analyser method
NOTEThe measurement precision is dependent on the DUT polarization dependent loss (PDL) when a coherentwavelength tunable source is used.
5.2.1 In accordance with Figure 3, the device under test (DUT) is connected to thebroadband source and the optical spectrum analyser. After setting every measuring parameterof the optical spectrum analyser (wavelength range，wavelength resolution，optical powerrange and averaging times and so on), measure and record the wavelength dependence ofoptical output power level of the DUT,P.