Data Sheet SFP GLC-BX-D or GLC-BX-U

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Tom Randstrom Wed, 03/24/2010 - 08:13
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The specification sheet for the BX is in the standard 1GE SFP data sheet (url below):


<http://www.cisco.com/en/US/prod/collateral/modules/ps5455/ps6577/product_data_sheet0900aecd8033f885.html>


The IEEE 802.3 Section 5 (url below) which includes the BX10 spec, which these SFPs are compatible, outlines 10-12 BER over operating range of device.


<http://standards.ieee.org/getieee802/802.3.html>


Hope this helps.


Tom

Thank you for your prompt reply!


I've already taken a look at this doc, but it is not enough, I mean, It's clear that the SFP will be compliant the IEEE standard, but I'm not sure about the performance of the SPF working with low power, I'm interested in the Bit Error Rate in the edge around -19 dBm for these SFP. I don't want to look sceptical but I doubt that in this range of power -16 dBm to -19 dBm, the SFP is able to keep a BER of 10-12. The only way would be to test it, or get the info from the manufacturer, in this case Cisco....simple graphic representing dBm - BER, from my point of view, subjective, is basic.


I would be thankful If some can help my out with this quandary.


Cheers
Cesar Prados

Tom Randstrom Wed, 03/24/2010 - 10:23
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Cesar,


I believe you may be being overly cautious.  The IEEE specs are designed to allow the consistent deployment of the technology.  The specs, in Section 59, specify how a compliant BX10 device should operate (I've attached document of relavant section).


Do you require the same optical performance graphics for  the other SFP types (SX, LX, etc.)?  Cisco purchases SFP's from multiple vendors, each one is required to meet the IEEE specs. You would have to contact a Cisco Representative to see if they could  request a representative graphic from the product management organization.


I hope this helps!


59.7.11 Receive sensitivity measurements
Receiver sensitivity is defined for the random pattern test frame (see 59.7.1) and an ideal input signal quality
with the specified extinction ratio. The measurement procedure is described in 58.7.10. The sensitivity shall
be met for the bit error ratio defined in Table 59–5  or Table 59–7
as appropriate. Stressed sensitivity is
described in 59.7.14 and 58.7.11.


Table 59–7—1000BASE-BX10-D and 1000BASE-BX10-U receive characteristics
Description 1000BASE-BX10-D 1000BASE-BX10-U Unit
Signaling speed (range) 1.25 ± 100 ppm GBd
Wavelength (range) 1260 to 1360 1480 to 1500 nm
Bit error ratio (max) 10–12
Average receive power (max) –3 dBm
Receive sensitivity (max) –19.5 dBm
Receiver sensitivity as OMA (max) –18.7 (13.4) dBm (µW)
Receiver reflectance (max) –12 dB
Stressed receive sensitivity (max)a –15.4 dBm
Stressed receiver sensitivity as OMA (max) –14.6(35)dBm(µW)
Vertical eye-closure penalty (min)b 2.6 dB
Receive electrical 3 dB upper cutoff frequency (max) 1500 MHz
Signal detect threshold (min) –45 dBm

Hi,


thank you for the reply!


1) As you said "The specs, in Section 59, specify how a compliant BX10 device should operate", and in our case we have to be overly cautious, we have to lay fiber till 9 km without optical regenerator and BER approx to 10-12... Hence, If we can trust the optic components' performance we can focus our efforts in others problems.


2) And actually it's what I did, I contact Cisco and a Cisco distributor and I got nothing, that it's the reason I asking in the forum...


Cheers,


Cesar

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