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[802.3ae] Bad idea...not including FP laser in PMD



Dear 802.3ae members

            I understand that this is an old topic, but I still strongly believe that it is a bad idea not to include 1310 nm Fabry-Perot (FP) lasers in the PMD.  Let me re-cap some of the advantages of FP lasers:

  1. Low cost comparing to DFB lasers: high yield single-growth wafer process, less sensitive to back reflection that eliminates the need for isolator in package.  (1.3 VCSEL yield/cost is not clear now, therefore it is hard to compare.)
  2. Edge emitting lasers (FP and DFB) are more mature technology and have been deployed in market for many years.  Both lasers are available today through multiple vendors.
  3. FP laser can handle at least 0 to 2km (some test even indicate 7km is possible). And majority of the 10G Ethernet applications fall into this range.
  4. Some companies are shipping transceiver/transponder products using 1310 FP lasers today, but unfortunately they are being treated as non-802.3ae standard products.

The current 1310 PMD specification has a 30 dB SMSR spec that prohibits the use of FP lasers.  I believe that it is to the best interest of our industry to standardize a PMD based on 1310 nm FP lasers.  If there is a way to start a new project or modify the current specifications to include FP lasers, Iíll love to lead an effort on it.

 

Norman Kwong

CTO

Archcom Technology

Office: 626-969-0681 x121