16 Sept 04 IEEE802.3aq Channel model ad hocTask 2: Time variation and modal noise

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Task 2 update: Time variation and modal noise study

16 Sept 04 IEEE802.3aq Channel model ad hocTask 2: Time variation and modal noise

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Task 2 Progress To date:• 'Standard link' for modeling and experiments agreed

– 4 connectors with 2 connectors at 7micron offset (worst case consistent with preceding standards and existing link specs)

• Adopted GR-63-CORE describing in-building environments • office environment vibration tests at 'constant acceleration' (0.1G &

1G) from 5-100 Hz (vibration amplitude ~ 1/f2)

Active:• Experiments to determine relationship of perturbation spectrum to

modal noise spectrum just started. Initial experiments at 10-100Hz, 3-5mm p-p movement

• up to 3x frequency multiplication observed

• Study of temperature effects in progress – Comprehensive list of mechanisms compiled and size of each effect being

determined. Most significant effects will be for further study

• Modal Noise calculations in progress – not likely to be ready for September interim

16 Sept 04 IEEE802.3aq Channel model ad hocTask 2: Time variation and modal noise

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Standard link: Agreed worst-case test configuration for channel variance measurements

from '62 MMF con loss and draft worst case configuration' - David Cunningham

16 Sept 04 IEEE802.3aq Channel model ad hocTask 2: Time variation and modal noise

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Vibration tests representative of office environment

• GR 63 CORE• describes office environment vibration tests at

'constant acceleration' (0.1G & 1G) from 5-100 Hz – (vibration amplitude ~ 1/f2 )

• Perturbation to be applied to 10m fibre loop prior to main MM fibre

– 0.1G acceleration at 1Hz corresponds to a 2.5cm perturbation amplitude - similar to TIA/EIA-455-203 fibre shaker

– 1G acceleration at 1Hz corresponds to 25cm amplitude - similar to 'shaking the fibre'

from summary of GR-63-CORE in 'LRM080404' - John Dellasasse

16 Sept 04 IEEE802.3aq Channel model ad hocTask 2: Time variation and modal noise

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Summary table of temperature variation impact

from Sept 15th rev of 'Temperature variation' - Petre Popescu

16 Sept 04 IEEE802.3aq Channel model ad hocTask 2: Time variation and modal noise

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Experimental study of channel variation vs perturbation frequency

• Experimental test set up and intitial results are described in document: 'TimevarianceinMMFlinks-initialtestresults' - Robert Coenen