{"id":1083,"date":"2013-03-12T11:19:55","date_gmt":"2013-03-12T07:19:55","guid":{"rendered":"https:\/\/mpc-oman.com\/?page_id=1083"},"modified":"2013-03-12T11:19:55","modified_gmt":"2013-03-12T07:19:55","slug":"coupled-power-ratio-of-multimode-fiber","status":"publish","type":"page","link":"https:\/\/mpc-oman.com\/?page_id=1083","title":{"rendered":"Coupled Power Ratio of Multimode Fiber"},"content":{"rendered":"

10G: <\/strong>Coupled Power Ratio Measurement Procedure<\/h1>\n
Written by Brian Crook – 2004. \u00a9 Kingfisher International<\/div>\n

\"prev\"<\/a> \"add <\/a> \"print\" <\/a> \"next\"<\/a> Introduction<\/h2>\n

This instruction describes the procedure for determining the modal launch condition and category of a light source or fiber end by measuring its coupled power ratio (CPR).<\/p>\n

Scope<\/h2>\n

This instruction is applicable for all multimode light sources with particular emphasis on LED sources.<\/p>\n

This instruction has been written around 50 \u00b5m fiber core CPR measurement. For measuring CPR of 62.5 \u00b5m systems, substitute 62.5 \u00b5m MM patch leads and lookup table data as appropriate .<\/p>\n

Apparatus Required<\/h2>\n
    \n
  • Power meter with Germanium detector, or Silicon detector if only working at 850 nm.<\/li>\n
  • 50 ?m patch lead, 1-5 meters long.<\/li>\n
  • Single mode patch lead, standard type for 1300 nm, 1-5 meters long, configured with one 30 mm diameter loop.<\/li>\n
  • Single mode patch lead, special type for 850 nm, 1-5 meters long, configured with one 30 mm diameter loop.<\/li>\n
  • Through connects to suit instruments and patch-leads.<\/li>\n<\/ul>\n

    Note: Connectors on the above patch leads shall have losses <= 0.5 dB (@ 850 & 1300 nm).
    \nNote: Connectors with PC finish are best as they inhibit Fresnel reflections.<\/p>\n

    Steps<\/h2>\n
      \n
    1. Check that all patch-leads and connectors are clean.<\/li>\n
    2. First measurement<\/i> (MM)
      \nConnect a 50 ?m MM patch-lead between the light source and a power meter as in Figure 1, and zero the meter.<\/p>\n

      Note: Keep the patch-lead as straight as possible (avoid bends of less than 50 mm diameter) as could affect the modal power distribution and hence the measurement accuracy).<\/p>\n

      \"multimode<\/p>\n

      Figure 1 \u2013 First MM measurement<\/b><\/p>\n<\/li>\n

    3. Final measurement<\/i> (SM)
      \nLeave the MM lead connected to the light source, and connect the correct SM patch-lead. Make a 30 mm diameter loop, which acts as a mode filter.<\/p>\n

      \"coupled<\/p>\n

      Figure 2 \u2013 Final SM measurement<\/b><\/p>\n

      Measure & record the power output (L2) of the MM to SM pigtail combination.<\/li>\n

    4. CPR coefficient calculation<\/i>
      \nAs meter was zeroed the CPR = – L2 (dB)<\/b>
      \nOtherwise the CPR coefficient is calculated as:
      \nCPR = L1 \u2013 L2 (dB)<\/b>
      \n– Round to the nearest 0.1 dB<\/li>\n
    5. Mechanical instability<\/i>
      \nShould mechanical instability cause variations >0.5 dB. The standards specify repeating the measurement 5 times and averaging the results.<\/li>\n
    6. CPR category<\/i>
      \nUse the look up table below to determine the CPR Category of the light source.<\/li>\n<\/ol>\n\n\n\n\n\n\n\n
      \n

      Table 1 \u2013 850 nm CPR Categories<\/h2>\n<\/td>\n<\/tr>\n

      Fibre Size<\/b><\/td>\nCategory 1<\/b>
      \nOverfilled<\/td>\n      		Category 2<\/b><\/td>\nCategory 3<\/b><\/td>\nCategory 4<\/b><\/td>\nCategory 5<\/b>
      \nGreatly under filled<\/td>\n<\/tr>\n
      50 ?m<\/td>\n20-24<\/td>\n16-19.9<\/td>\n11-15.9<\/td>\n6-10.9<\/td>\n0-5.9<\/td>\n<\/tr>\n
      62.5 ?m<\/td>\n25-29<\/td>\n21-24.9<\/td>\n14-20.9<\/td>\n7-13.9<\/td>\n0-6.9><\/td>\n<\/tr>\n
      100\/140 ?m<\/td>\n30-34<\/td>\n26-29.9<\/td>\n18-25.9<\/td>\n10-17.9<\/td>\n0-9.9<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

       <\/p>\n\n\n\n\n\n\n\n
      \n

      Table 2 \u2013 1300 nm CPR Categories<\/h2>\n<\/td>\n<\/tr>\n

      Fibre Size<\/b><\/td>\nCategory 1<\/b>
      \nOverfilled<\/td>\n      		Category 2<\/b><\/td>\nCategory 3<\/b><\/td>\nCategory 4<\/b><\/td>\nCategory 5<\/b>
      \nGreatly under filled<\/td>\n<\/tr>\n
      50 ?m<\/td>\n16-20<\/td>\n12-15.9<\/td>\n8-11.9<\/td>\n4-7.9<\/td>\n0-3.9<\/td>\n<\/tr>\n
      62.5 ?m<\/td>\n21-25<\/td>\n17-20.9<\/td>\n12-16.9<\/td>\n7-11.9<\/td>\n0-6.9<\/td>\n<\/tr>\n
      100\/140 ?m<\/td>\n26-30<\/td>\n22-25.9<\/td>\n15-21.9<\/td>\n8-14.9<\/td>\n0-7.9<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      References<\/h2>\n

      TIA\/EIA 526-14A OFSTP-14, Optical Power Loss Measurements of Installed Multimode Fiber Cable Plant IEC 61280-4-1 Fibre-Optic Communication Subsystem Basic Test Procedures \u2013 Part 4-1: Test procedures for fibre-optic cable plant links \u2013 Multimode fibre-optic cable plant attenuation measurement.
      \nIEC 61300-3-31 Fibre optic interconnecting devices and passive components \u2013 Basic T&M procedures \u2013 Part 3-31: Examinations and measurements \u2013 Coupled power ratio measurement for fibre optic sources.<\/p>\n

      Note:<\/h2>\n

      At time of writing it is understood that the standard bodies ISO\/IEC, IEC and CLC are seeking a method to create a multimode, mode conditioning patch cord which can be used to create a light source with a defined launch condition. \u2018Launch\u2019 date is scheduled for September 2004.<\/p>\n","protected":false},"excerpt":{"rendered":"

      10G: Coupled Power Ratio Measurement Procedure Written by Brian Crook – 2004. \u00a9 Kingfisher International Introduction This instruction describes the procedure for determining the modal launch condition and category of a light source or fiber end by measuring its coupled power ratio (CPR). Scope This instruction is applicable for all multimode light sources with particular […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1065,"menu_order":0,"comment_status":"open","ping_status":"open","template":"","meta":[],"_links":{"self":[{"href":"https:\/\/mpc-oman.com\/index.php?rest_route=\/wp\/v2\/pages\/1083"}],"collection":[{"href":"https:\/\/mpc-oman.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/mpc-oman.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/mpc-oman.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mpc-oman.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1083"}],"version-history":[{"count":2,"href":"https:\/\/mpc-oman.com\/index.php?rest_route=\/wp\/v2\/pages\/1083\/revisions"}],"predecessor-version":[{"id":1089,"href":"https:\/\/mpc-oman.com\/index.php?rest_route=\/wp\/v2\/pages\/1083\/revisions\/1089"}],"up":[{"embeddable":true,"href":"https:\/\/mpc-oman.com\/index.php?rest_route=\/wp\/v2\/pages\/1065"}],"wp:attachment":[{"href":"https:\/\/mpc-oman.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1083"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}