Why is 10GBase-SR difficult to make?
10GBase-SR put great constraints on transceiver designs
• 300 meters * 10G = 3,000 MHz*km bandwidth length products
(BWLP) of link
– 1GE only has a bandwidth length product of ~1,000 MHz*km
– OM3 fiber has a BWLP of 2,000 MHz*km, so the BWLP of the link exceeds that of
the fiber by putting stress on the transceiver design
• 100 meters * 10G = 1,000 MHz*km BWLP of each lane for 100G or
40G
– With a 66% reduction of the BWLP of the 10GBase-SR link, less stress is placed on
the transceiver design.
The 3,000 MHz*km BWLP lead to many PMDs for 10GBase-SR
• 300 Pin MSA, XENPAK, X2, XPAK, XFP and soon QSFP
• Minimal volume production still and SFP+ is delayed until late this year or even next year
10GE Copper solutions are also stuck in the “difficult to make/use”
category with a BWLP of 1,000 MHz* km since it spans 100 meters
• 10GBase-T – high power consumption at 6-15 Watts/port
• 10GBase-CX4 – cumbersome twinax pairs
