02 | Keysight | N4917B Optical Receiver Stress Test Solution - Solution Brochure
Repeatable Optical Receiver Stress Test for
100GBASE-LR4/ER4/SR4
In recent years, transmission speeds in gigabit ethernet have continously increased
from 10 Gb/s to 40 Gb/s and are now approaching the 100 Gb/s speed class. 10 Gb/s
Ethernet was designed based on a 10.3125 Gb/s line rate on one single-mode fiber per
direction. The 40 Gb/s Ethernet speed class changed this to an architecture using the
same 10.3125 Gb/s line rate but using four optical wavelengths in the O-Band on one
single-mode fiber per direction. This increased the transmission capacity by a factor of
four, without a need to make changes to the speed of the electrical components. In the
last few years the 100 Gb/s speed class has been established, increasing the electrical
line rate from 10.3125 Gb/s to 25.78125 Gb/s. It also uses both four optical wavelengths
on one fiber as well as multiple fibers with one optical wavelength per fiber.
The conformance test specification for 100 Gb/s transmission speed class is defined in
the IEEE 802.3 standard, clause 88 for 100 Gb/s Ethernet long reach (LR4) and extended
reach (ER4) and clause 95 for 100 Gb/s Ethernet short reach (SR4).
The N4917B optical receiver stress test solution provides an automated stressed receiver
sensitivity test in accordance with the 100GBASE-LR4, ER4 and SR4 test specifications.
In order to do this kind of test, several test instruments such as a bit error ratio tester,
digital sampling oscilloscope, optical reference transmitter and tunable laser source are
required to operate together to achieve a compliant, repeatable optical stressed eye.
This stressed eye is then fed to the receiver under test, where bit error ratio is measured
under the stress conditions as defined in the standard.
The N4917B solution provides:
– Automated calibration of the optical stressed eye according to IEEE 802.3 clause 88
and 95.
– Calibration of ER, VECP/SEC, J2, J4, J9, OMA parameters
– Repeatable results
– Adjustable target values for ER, VECP/SEC, J2, J4, J9, OMA
– Jitter tolerance compliance and margin test
– Electrical loop back or optional DUT control interface for full automated JTOL test
– Remote control of all the test instrumentation
– For this, the N4917B includes the following key equipment:
– a high performance bit-error-rate tester
– an optical reference transmitter for 25.78125 Gb/s
– a tunable laser covering the O-band for LR4/ER4 or a 850nm laser for SR4
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