RE: Proposed WAN vs. LAN Terms (Ethernet HSSG)

["Yokouchi, Jim" <JYokouchi@sumitomoelectric.com>]

Hi everybody,

Please allow me jumping in.
I have some comments from the view point of an optical component supplier.
An isolator that is used in a LD module should not be a expensive parts
among entire 10Gbps optical module.  
It is also much cheaper than the inline isolators like in a WDM system
because of no polarization concern.

DFB-LD should have it.
FP-LD might be OK without it for very short distance.
I would put an isolator on  to keep a better loss budget.

I believe that a directly modulated laser is very potential solution for
short reach and intermediate reach application in terms of both cost and
reliability.  
It's so simple.

I have one thing to tell you regarding directly modulated laser.
A modulation speed is the trade off performance versus extinction ratio of
output signal.
If we could relax the extinction spec, we would open device selection,
including suppliers, significantly wide, I believe.  It reduces a cost, of
course.

Even Gigabit Ethernet, only good laser can be used like ours.
It's not commercial thing, but a serious joke.

However, if we persist in a tight spec like OC-192, we might miss a
potential solution.
If we can use it, we should use it.

Jim Yokouchi
Sumitomo Electric Lightwave Corp.
jyokouchi@sumitomoelectric.com


> -----Original Message-----
> From:	Buckman, Lisa [SMTP:lbuckman@exch.hpl.hp.com]
> Sent:	Wednesday, May 12, 1999 7:39 PM
> To:	'bgregory@molex.com'; BRIAN_LEMOFF@HP-PaloAlto-om16.om.hp.com
> Cc:	stds-802-3-hssg@ieee.org; xclairardin@molex.com; twhitlow@molex.com
> Subject:	RE: Proposed WAN vs. LAN Terms (Ethernet HSSG)
> 
> 
> Bryan,
> In response to this comment you made: 
> 
> "I've heard a number of individuals state 
> that a directly modulated 10 Gb laser is possible.  Lucent seemed to be 
> proposing this at the Austin meeting (I believe their eye pattern was from
> one 
> of these devices).  If this was a directly modulated uncooled DFB without 
> isolator, then I believe it would be by far the lowest cost and the most 
> straight forward."
> 
> Just wanted clarify that the directly modulated, uncooled DFB that Lucent
> discussed at the Austin meeting, DOES have an isolator.  I clarified this
> with Lucent after their presentation.  The directly modulated, uncooled FP
> that they discussed does not have an isolator.
> 
> Lisa Buckman
> Hewlett-Packard Laboratories
> lbuckman@hpl.hp.com
> 
> 
> 
> -----Original Message-----
> From: bgregory@molex.com [mailto:bgregory@molex.com]
> Sent: Monday, May 10, 1999 2:34 PM
> To: BRIAN_LEMOFF@HP-PaloAlto-om16.om.hp.com
> Cc: stds-802-3-hssg@ieee.org; xclairardin@molex.com; twhitlow@molex.com
> Subject: Proposed WAN vs. LAN Terms (Ethernet HSSG)
> 
> 
> Hi All,
> 
> Just a quick question, is there a "term" defined for the very long reach
> version
> of 10GEth?  These definitions seem to be important to our discussion.  As
> Brian 
> from HP stated, we're not being clear on the specific application
> environment.  
> I'd suggest something like:
> 
> 10,000Base-SX
>         Multi-mode
>         Wavelength ~ 850nm
>         I'd guess WWDM only
>         300m reach over 62.5um fiber
> 
> 10,000Base-LX
>         Single-mode (maybe also multi-mode)
>         Wavelength ~ 1310nm or 1550nm
>         WWDM, Serial or MAS
>         10km reach
> 
> 10,000Base-EX   (EX=Extended Length)
>         Single-mode
>         Wavelength ~ 1550nm 
>         DWDM or Serial
>         Externally modulated
>         Long Reach
>         (similar to what Bill St. Arnaud is talking about)
> 
> Also, I've seen some comments on the serial version of the 10,000Base-LX
> that 
> assume it'll be externally modulated.  I've heard a number of individuals
> state 
> that a directly modulated 10 Gb laser is possible.  Lucent seemed to be 
> proposing this at the Austin meeting (I believe their eye pattern was from
> one 
> of these devices).  If this was a directly modulated uncooled DFB without 
> isolator, then I believe it would be by far the lowest cost and the most 
> straight forward. Regarding the 10,000Base-EX, I'd (obviously) assume that
> this 
> was only externally modulated.
> 
> Regards,
> Bryan Gregory
> bgregory@molex.com
> 630/512-8520