N4917BACA Optical Receiver Stress Test Solution 100 Gb/s Ethernet

N4917BACA Optical Receiver Stress Test Solution 100 Gb/s Ethernet

10GBASE-LR/-ER/-SR, 25GBASE-LR/-ER/-SR, 40BASELR4/-ER4/-SR4, 100BASE-LR4/-ER4/-SR4 and MSAs

Introduction

Complete optical receiver stress test solution for 100GbE optical transceivers with automated stress eye calibration and performance compliance testing

Optical Receiver Stress Test for 10/25GBASELR/ER/SR, 40/100GBASE-LR4/ER4/SR4 and MSAs

In recent years, transmission speeds in gigabit ethernet have continuously increased from 10 Gb/s to 40 Gb/s and are now reaching 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 10/40/100 Gb/s transmission speed class is defined in the IEEE 802.3 standard. The N4917B optical receiver stress test solution provides an automated stressed receiver sensitivity test in accordance with the 10/25/40/100 GBASE test specifications as well as with the following 100G Multi Source Agreements: CLR4, CWDM4, 4WDM and PSM4. 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 N4917BACA solution provides:

• Automated calibration of the optical stressed eye according to IEEE 802.3 clauses 52,86,87,88,95,112 and 114 and related MSAs 
• 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 N4917BACA includes the following key equipment:

• A high-performance bit-error-rate tester 
• An optical reference transmitter up to 25.78125 Gb/s 
• A tunable laser covering the O-band for LR4/ER4 or an 850 nm laser for SR4 and a fixed 1310/1550 laser for 10GBASE

Typical Setup for 100GBASE-LR4/-ER4 Optical Stress Test

The N4917BACA optical receiver stress test solution consists of a M8040A BERT for electrical signal generation plus an arbitrary waveform generator or a pulse signal generator for stress generation; an electro-optical converter that modulates the optical signal and a digital sampling oscilloscope which is required for calibration of the stressed eye. An example setup for 100GBASE-LR4/-ER4 using four 25 Gb/s lanes on four wavelengths in the O-band is shown in Figure 2, which assumes the use of a 100 GAUI-4 electrical interface. The IEEE 802.3ba standard establishes two ways to provide a clock signal to the digital sampling oscilloscope:

• Using the ‘clean clock’ of the pattern generator or 
• Extracting it from the stressed signal using an external clock recovery.