Fukouka-san,
Thank you for your comment; these terms are often confused with each other and was one of the reasons for the letter from ISO/IEC SC25/WG3 to IEEE 802.3 in 2010.
Optical return loss for individual events, i.e. the reflection above the fiber backscatter level, relative to the source pulse, is called reflectance.
Optical return loss is given in units of dB and always a negative value for passive optics, with values closer to 0 representing larger reflections (poorer connections).
Return loss for the entire fiber under test, including fiber backscatter and reflections and relative to the source pulse, is called Optical Return Loss (ORL). It is also given
in units of dB, but always a positive value, with values closer to 0 dB representing more total light reflected.
Here is an example of how these are specified in Clause 52, 10GBASE-S:
52.14.2.2 Maximum discrete reflectance
The maximum discrete reflectance for 10GBASE-S shall be less than –20 dB.
Steven E. Swanson
Senior Standards Manager
Distinguished Associate
Global Technology & Industry Standards
MT&E
Corning Optical Communications
4200 Corning Place
Charlotte, NC 28216
m 607-725-1129
Standards are a bridge between markets and technologies; whoever controls the bridge controls the future…
From: Takashi Fukuoka <fukuoka-takashi@xxxxxxxxx>
Sent: Wednesday, February 24, 2021 1:13 AM
To: Swanson, Steven E <SwansonSE@xxxxxxxxxxx>; STDS-802-3-OMEGA@xxxxxxxxxxxxxxxxx
Subject: [EXTERNAL]--Re: [802.3_OMEGA] Baseline test for IEEE 802.3cz PMD/MDI
Hello Steve,
Thank you for your contribution.
I have a comment on the below statement:
> 300.8.2.2.2 Maximum discrete reflectance
> The maximum discrete reflectance shall be less than TBD dB.
According to the other IEEE802.3 optical PHY standards, the optical reflection
(optical reflection tolerance for optical transmitter) shall be less than -12dB.
I think we'd better to follow the wisdom of old people as far as there is no particular reason.
RIN influenced by optical reflection is varied by the design of both VCSEL chip and optical coupling system,
so that it will be easier (with lower cost) to purchase them in the market.
The attached letter might be good to understand the definition of optical reflection of the channel.
Best regards,
Takashi Fukuoka
On 2021/02/24 0:49, Swanson, Steven E wrote:
All,
On the IEEE 802.3cz call today, I provided a contribution on baseline text for the PMD/MDI (attached). I would like to make a motion to adopt this text as part of the baseline text at our next interim meeting as we move to D1.0.
The purpose of this note is twofold:
- Can I ask you to review the contribution and let me know if you have any comments to improve the text?
- Can I ask you to review the contribution and let me know if I can add you as a supporter for the contribution?
I would like to get your input prior to Friday, March 5 so I can make any necessary changes and submit for consideration by IEEE 802.3cz at our March 16 interim meeting.
Thanks,
Steve
Steven E. Swanson
Senior Standards Manager
Distinguished Associate
Global Technology & Industry Standards
MT&E
Corning Optical Communications
4200 Corning Place
Charlotte, NC 28216
m 607-725-1129
Standards are a bridge between markets and technologies; whoever controls the bridge controls the future…
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福岡 隆（Takashi Fukuoka）
Sumitomo Electric Industries, Ltd.
TEL:090-8139-4491 (Direct)
e-mail: fukuoka-takashi@xxxxxxxxx
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