single fiber, single wavelength, gbe / fe transceiver...
TRANSCRIPT
IEEE 802.3ah May. 2002 1
Single Fiber, Single wavelength, GbE / FE transceiverForeign Ingress Issues
Meir Bartur, Zonu, Inc.
IEEE 802.3 ah interimMay 2002
IEEE 802.3ah May. 2002 2
Table of Contentn “Foreign ingress” light coming back into the
laser – single wavelength (action item 3)n Measurements
IEEE 802.3ah May. 2002 3
“Foreign ingress” light coming back into the laser – single wavelength
n Actual measurements set-up Preliminary tests
n Report
Interfering Source+0.5dBm
TRANSCEIVER #2
1310nm/1310nm
TRANSCEIVER SFP #1
Tx under test1310nm/1310nm
Splitter 3dBFiber
Fiber Fiber
Fiber
HP7000 BIT ERROR TEST SET
Transmit data
patterns
Receive data pattern
OPTICAL ATTENUATOR EXFO FVA-60B
Coax
Coax
Coax
TX
TX
Reference Detector
+LNA
ElectricalSpectrumAnalyzer
Coax
Selector
OPTICAL SPECTRUM ANALYZER
Fiber
Fiber
Fiber spool 10km
Selector
IEEE 802.3ah May. 2002 4
Measurementsn Initial Test
u Link – Pout = - 5.7dBm Pingress = -2.3dBm BOTH MEASURED at the Transceiver fiber interface
u Measured sensitivity in the presence of direct light into the laser
u Unit 1 was cooled to get a wavelength sweep to cover the overlap)
u Both sensitivity and noise floor were measured.
IEEE 802.3ah May. 2002 5
Results Measured sensitivity in the presence of direct light into the laser
n The Transceiver under test was placed in an environmental chamber ant temperature was swept from –20°C to 50°C to ensure wavelength overlap.
n Link – Pout = - 5.7dBm Pingress = -2.3dBm BOTH MEASURED at the Transceiver fiber interfaceu Unit 1 was cooled to get a wavelength sweep to cover
the overlap) n Sensitivity of reference receiver AND RIN of the
“contaminated” Tx were measuredu Worst case sensitivity penalty (when wavelength overlap)
0.3 dBu Worst case RIN degradation (when wavelength overlap)
1dB
n Since “foreign ingress” is high power low loss situation – the above penalties DO NOT MATTER
IEEE 802.3ah May. 2002 6
“Foreign ingress” light coming back into the laser – single wavelength
Interfering SourceForeign Ingress
Transmitter1310nm
OPTICAL RECEIVER
1310nm
TRANSCEIVER SFP Tx under test
1310nm/1310nm
Coupler 3dB
Fiber
Tx = -7.8dBm
OPTICAL ATTENUATOR EXFO FVA-60B
HP7000 BIT ERROR TEST SET
Transmit data
patterns
Receive data
pattern
Coax
OPTICAL SPECTRUM ANALYZER
Fiber spool 10km
Coupler 3dB
Fiber
Coax
OPTICAL ATTENUATOR EXFO FVA-60B
Coupler 3dB
Fiber Fiber
Fiber Fiber
Fiber
Fiber
Fiber
+0.5dBm
Couplers
• Reflectance < -55dB
• Directivity > 55dB
(a) Modulated source
(b) Un modulated source
O
V
E
N
IEEE 802.3ah May. 2002 7
FOREIGN INGRESS SOURCE - MODULATED (a)
IEEE 802.3ah May. 2002 8
Single Fiber Single λ SFP (a,b)
IEEE 802.3ah May. 2002 9
Foreign Ingress Modulated +Single Fiber Single λ SFP (a)
IEEE 802.3ah May. 2002 10
FOREIGN INGRESS SOURCE UN MODULATED (b)
IEEE 802.3ah May. 2002 11
Foreign Ingress UnModulated +Single Fiber Single λ SFP (b)
IEEE 802.3ah May. 2002 12
Foreign Ingress Interference on Tx(reference Rx sensitivity)Exact wavelength/modes overlap
Effect of Foreign Ingress
1.0E-11
1.0E-10
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
-28.0 -27.0 -26.0 -25.0
Sensitivity [dBm]
Bit
Err
or
Rat
e
MODULATED FOREIGNINGRESS SOURCE
UNMODULATED FOREIGNINGRESS SOURCE
NO FOREIGN INGRESS SOURCE
Pout = -8dBm Pingress = -3dBm
The sensitivity measured at a receiver that accepts the output from “contaminated”source
IEEE 802.3ah May. 2002 13
Major installer of 1310/1310 links could notinduce foreign ingress effects
n "Marconi is a pioneer in the deployment of fiber optics in the last mile portion of the network. Over the past 5 years, Marconi has deployed more than 100,000 single fiber, full-duplex, single mode 1310nm optical links in the access network.”
Mark Cannata, Vice President, Marconi, North American Product Line Management and Marketing, Access
n We have extensively tested such interference (foreign ingress, MB) with FP using the 100BaseT single fiber transport we use from XXXX but could not induce such phenomena.
George BuAbbud, Chief Scientist Access Systems, Marconi
IEEE 802.3ah May. 2002 14
Conclusionn Foreign Ingress – IS NOT AN ISSUE
u Applicable for very short reach (strong incoming signal)
u Effect is either non-detectable or very smalu Actual margins under such conditions –
more than 10dB
IEEE 802.3ah May. 2002 15
PMD Specification