RE: PAM5 Objectives
Pat,
Using a PAM-5 implementation including adaptive equalization, all reaches
should be achievable. From 0-10 km, a 1310 DFB should work. fine. At 40 km
(and beyond), it seems to me that the pre-coding may well help minimize
chromatic dispersion, thus creating a dramatic advantage. My guess is that,
in order to achieve 40 km, the serial guys will wind up using an externally
modulated 1550 DFB. If we can directly modulate the laser, we save several
hundred dollars per laser. It may be possible to do a single device which
will meet all reach objectives, but to do so will probably require active
feedback to the laser driver to manage link margins.