Re: [8023-10GEPON] Raman cross-talk calculations

[=?ks_c_5601-1987?B?sei6wLHU?= <bongkim@xxxxxxxxxx>]

Dear all,

 

I have also calculated the allowed maximum launch power of the digital wave as a function of the wavelength.

The used parameters are almost same as the parameters used in the Mao's calculation. (presented in Sanfransisco meeting, June 2007)

The attached file is the results.

 

Analog signal needs more than 43 dB, 33 dB, 27 dB CNR for AM-VSC analog,  256 QAM, 64 QAM signal format, respectively. [Ref: ANSI/SCTE 40 2004]

 

For the 43 dB CNR, the maximum launch power was about 10 dBm and 11 dBm at 1530 nm and 1570 nm, respectively. The results are slightly higher than Effenberger's.( Here, I didn't consider an 1G signal.)

 

On the other hand, the results were quite different from Mao's results. (presented in June this year)

The simulation condition of Mao was 51 dB crostalk. 

However, because the CNR depend on the SRS crosstalk in the SRS dominant region,

the required CROSSTALK is almost same as the required CNR.

So, I have calculated the lanched power for the acquire 43 dB crosstalk induced by SRS.

 

Sincerely yours,

Bong Kyu Kim

Bong Kyu Kim, Ph.D.

Senior Research Staff

Optical Access Tech. Team

BcN Research Lab.

Electronics and Telecommunications Research Institute

Tel: +82-42-860-1344, Fax: +82-42-860-5213

E-mail: bongkim@etri.re.kr

-----¿øº» ¸Þ½ÃÁö-----
From: "Frank Effenberger" <feffenberger@HUAWEI.COM>
From Date: 2007-09-07 ¿ÀÈÄ 1:54:04
To: "STDS-802-3-10GEPON@LISTSERV.IEEE.ORG" <STDS-802-3-10GEPON@LISTSERV.IEEE.ORG>
Cc:
Subject: [8023-10GEPON] Raman cross-talk calculations

 

Dear all,

 

I note that there was a contribution regarding Raman interactions.  I have concerns that the calculations used there do not reflect the actual operational cases and trade-offs of fiber distance loss and Raman interaction strength, the significant effect of intra-office losses, the use of low-channel pre-emphasis, and so on.  

 

The bottom line is that these calculations have many parameters, and drawing any conclusions from un-audited calculations is dangerous.  

 

To help our progress, I have attached my calculation model for Raman cross talk with a video channel and 2 digital waves.  (This is a slight update of the file I used to prepare my January 07 presentation on this same topic.)  

 

There are two independent sheets.  The first computes the delivered CNR.  My calculations show that a 1G launch power of 2 dBm and a 10G launch power of 8 dBm seems to deliver more than 46 dBm (which is the current performance spec of important operators).  One must remember that typical in-office losses are 2 dB, so the maximum launch powers of the respective systems would be +4 and +10 dBm at the OLT face-plate.  That is a significant 3dB more than a number suggested recently. 

 

I invite others to work with the model, and provide their own comments. 

 

As a parting comment, I note that analog overlay use is rapidly declining.  I know of only one large application of such systems, and that user is now phasing out the support of analog.  So, the entire point may become moot. 

 

Sincerely,

Dr. Frank J. Effenberger      Ý×?к äïÝÒÚÏÌ«

Huawei Technologies USA

1700 Alma Drive, Plano TX 75075

Office (732) 625 3002

Cell (908) 670 3889

 

srs effect.ppt