1QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONSWhite Papersenko.com

Qualifying MPO Connector
at 105°C to Support OBO, NPOand CPO Applications
NOVEMBER 2023
Rev. 01

Tiger Ninomiya
Tatiana Berdinskikh
Takeshi Kasai

Invited authors from GlobalFoundries:
Jason Kim
Jae Kyu Cho
Norm Robson

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QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONS

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QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONS

Qualifying MPO
Connector at 105degC
to Support OBO, NPOand CPO Applications

Contents

4Introduction

4Test Setup

7

Test Results

7- Thermal Aging and Thermal Cycle

12- TWAL Test

13

Summary and Future Work

15References

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QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONS

1 Introduction
To support the exponentially increasing amounts of data traffic in
the data center, the industry has been considering a shift from thefront plate pluggable transceivers to emerging technologies suchas Onboard Optics (OBO), Near Packaging Optics (NPO), and CoPackaged Optics (CPO). OBO, NPO and CPO are the technology
concepts to locate optics closer to the system ASIC to reduce theelectrical connection distance between ASIC and Optics, which
will help to reduce the power loss and overall power consumption.
Bringing optics inside the system introduces new challenges ofhandling fibers and optical components inside the equipment box.
Another major challenge would be the needed changes to thereliability requirements on fiber optic components. Traditionally,reliability and qualification of fiber optic products follow Telcordia’s
General Requirements, IEC and TIA’s test specifications for opticalconnectors and optoelectronic devices. These tests are testing parts
up to 75~85°C conditions to age/accelerate, and simulate the longterm use of the products.

JEDEC has multiple testing standards for the microelectronics industry,
and is often used to qualify the substrates and components that arepackaged inside such communication equipment. For OBO/NPO/CPO
having optical parts packaged inside such equipment, the opticalparts would be required to also pass JEDEC testing specifications.
Some of the JEDEC environmental test requirements from JEDEC
test at temperatures beyond 100°C, which are temperatures beyond
where optical components have been typically tested.
Thus, Senko Advanced Components and GlobalFoundries have jointly
conducted tests under JEDEC conditions to support such applications
like OBO/NPO/CPO.

2 Test Setup
To qualify the optical connectors for the use in OBO/NPO/CPO
applications, we referenced test specifications by JEDEC, Temperature
Cycling (JESD22-A104F), High Temperature Storage Life (JESD22A103E.01) test specifications under JEDEC JC-14.1, and Reliability
Test Methods for Packaged Devices [1,2]. Both specifications havemultiple condition options. Condition G for Temperature Cycling,and Condition A for High Temperature Storage Life were selectedwith some modifications based on the availability of the test setup. The reliability testing requirements for Multi-Fiber opticalconnectors are specified by Telcordia standard GR-1435-CORE[3]. Based on the large high temperature difference between two

different specifications Telcordia 85°C and JEDEC 125°C, SENKO andGF performed initial temperature testing to set up the proper firstgoal and confirmed current fiber connectors were unstable above
120°C. So, the experiment goal was set 105°C instead of 125°C. Since
JEDEC documents do not specify the pass/fail criteria for opticalcomponents, we used the criteria using Telcordia GR-1435-CORE
for Multi-Fiber Optical Connectors. Table-1 shows the summary of
the test procedure and condition for each test. All connectors wereunmated during thermal aging and thermal cycling tests.

Table 1 Test conditions summary.

43
Thermal Aging

Thermal Cycle
Transmission with Applied LoadDuration

Test Parameter

Measurement

Reference

2000 hours

105oC

Insertion Loss
Return Loss
Endface Geometry

JESD22-A103E.01

1000 cycle-40 ~ 105oC
20c/min 30min dwell

Insertion Loss
Return Loss
Endface Geometry

JESD22-A104F

0° 0.49lbf
90° 0.49lbf

Insertion Loss
Return Loss

GR-1435-CORE
4.6.2.4-5

QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONSTest Setup
To verify the mechanical tolerance of the optical connectors
after aging, Transmission with Applied Load (TWAL) test was also
conducted under GR-1435-CORE 4.6.2.4. The 6 samples used for
Thermal Aging were also used for TWAL test.
Measurement of insertion loss (IL), return loss (RL), and end facegeometry were taken for all samples at the 1310nm and 1550nm
wavelength after 500th hour, and 1,000th hour of thermal aging,and 100th, 500th, 1000th and 2000th cycles of the thermal cycle.
For geometry, fiber height is reported on this whitepaper as fiberheight is critical for physical contact between mated connectors.
Other parameters such as radius of curvature and tilt angle are also
important but determined after the polishing process and are not

A weight to apply
0.49lbf force
Figure 1 TWAL setup.

as affected by high temperature environment. Whereas fiber height
could shift at high temperature if the epoxy reached the glass transition
temperature. This phenomenon is known as the fiber withdrawal. The
most significant changes in fiber height were reported for matedconnectors during thermal aging and thermal cycling [4, 5]. The fiber
withdrawal may impact the optical performance of connectors such as
IL and RL. Monitoring of IL, RL and Fiber Height was critical for this study.
Pass/fail distinction for the fiber height is based on IEC 61755-3-32 (seetable 1). TWAL insertion loss was measured while under load for 0deg
and 90deg. As the test jumpers were terminated with bare ribbon,
0.49lbf were applied for both 0deg and 90deg. TWAL was done usinga setup as below diagram (Picture 1) after the test jumpers has been
aged for 2,000 hours.

A weight to apply
0.49lbf force

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QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONSTest Setup
Jumpers under test were terminated using SENKO’s MPO Plus®
Premium Connector with Super Low Loss MT ferrule, 702F-F-SL12-Y01
and 702F-M-SL12-Y01 for female and male respectively. The connectors
were terminated using the ITU G.652 compliant single mode 12 fiberbare ribbon. Test jumpers used ribbon instead of jacketed cables as

the OBO application would require ribbon due to the limited space onboard. The 12 jumpers were prepared for the thermal cycling test and10 jumpers for the thermal aging test . The jumpers put into respective
chambers were un-mated and did not have dust caps. They were matedagainst master jumper to measure IL and RL for each interval.

Table 2 Relevant criteria/pass-fail distinction.

Criteria

Minimum

Maximum

Reference

1µm

3.5µm

GR-1435-CORE 4.2.1.1
IEC 61755-3-32

IL End of the Test-0.45dB

GR-1435-CORE 4.2.1.1*

IL Change Under Load-0.30dBGR-1435-CORE 4.2.1.2*

Fiber Height

RL End of the Test

60dB

GR-1435-CORE 4.2.1.1*

RL During Test Under Load60dB

GR-1435-CORE 4.2.1.1** Based on ultra performance

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QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONS

3.0 Test Results
3.1 Thermal Aging and Thermal Cycle
The result after Thermal Aging is shown in Table 3 and Figure 2-3
show the IL per fiber channel at 1310nm and 1550nm after 2,000
hours The IL results indicate there was no significant impact of 2,000
hours of aging and met the testing criteria. One sample had >0.35dB
IL on CH7 at the initial measurement at 1550nm. That same channel
showed an improvement after the aging test. The high loss was notobserved at 1310nm on the same channel. It is highly likely there
was a micro fiber bend that caused this measurement point, and lesslikely it was a connector component issue. Figure 4 shows the fiberheight distribution per channel for before and after the thermal aging
test. While there was more deviation observed after the aging, thisis a common phenomenon after thermal testing [4, 5], and all fiber
channels met the fiber height requirement. There were only minimalchanges of RL observed at the end of test for both TC and TA.

Table 3 Summary of thermal aging result after 2000 hours.

Measurement Taken
Initial Before Test

After 2000 Hours

1ItemMinMaxAve

StDev

Insertion Loss (dB) 1310nm

0.34

0.00

0.09

0.07

Insertion Loss (dB) 1550nm

0.36

0.01

0.09

0.06

Return Loss (dB) 1310nm

87.40

73.0

85.78

1.12

Return Loss (dB) 1550nm

83.40

74.0

81.90

0.92

Fiber Height (nm)2047.2

1704.2

1896.6

81.5

Insertion Loss (dB) 1310nm

0.33

0.03

0.18

0.08

Insertion Loss (dB) 1550nm

0.33

0.03

0.14

0.06

Return Loss (dB) 1310nm

84.8

70.9

79.4

3.49

Return Loss (dB) 1550nm

83.6

72.5

79.3

3.03

Fiber Height (nm)2477.11343.31952.2

277.6

There were 2 samples damaged due to the mishandling that are not reported in this paper.

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QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONS

Thermal Aging and Thermal Cycle
Insertion Loss per Channel at 1310nmFigure 2 Boxplot of insertion loss at 1310nm initial and after 2000 hours of thermal aging.

Insertion Loss per Channel at 1550nm

Figure 3 Boxplot of Insertion Loss at 1550nm Initial and After 2000 hours of Thermal Aging.

9QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONS

Thermal Aging and Thermal Cycle
Table 4 shows the results after 1,000 hours of thermal cycling. TheIL distribution per each fiber channel before and after the thermal
cycle are shown on Figure 5-6. Unlike the thermal aging test results
reported above, there was no obvious change observed. Similarly,

the fiber height variances before and after the thermal cycle test had
a minimum impact (Figure 7), and all the samples were confirmed
passing the criteria.

Fiber Height per Channel

Figure 4 Boxplot of fiber height at initial and after 2000 hours of thermal aging.

Table 4 Summary of thermal cycling result after 1000 cycles.

Measurement Taken
Initial Before Test

After 1000 Thermal Cycles

ItemMinMax

AveStDev

Insertion Loss (dB) 1310nm

0.30

0.01

0.11

0.07

Insertion Loss (dB) 1550nm

0.30

0.01

0.110.07

Return Loss (dB) 1310nm

85.0

72.0

81.0

2.3

Return Loss (dB) 1550nm

85.0

73.70

82.3

3.11

Fiber Height (nm)2478.81637.52097.6

81.5

Insertion Loss (dB) 1310nm

0.33

0.01

0.11

217.9

Insertion Loss (dB) 1550nm

0.30

0.01

0.10

0.07

Return Loss (dB) 1310nm

83.3

58.1

77.6

2.69

Return Loss (dB) 1550nm

83.5

59.6

78.2

2.57

Fiber Height (nm)2527.61498.12068.6

278.6

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QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONS

Thermal Aging and Thermal Cycle
Insertion Loss per Channel at 1310nm

Figure 5 Boxplot of insertion loss at 1310nm initial and after 1000 cylcles of thermal cycling.

Insertion Loss per Channel at 1550nm

Figure 6 Boxplot of insertion loss at 1550nm iInitial and after 1000 cycles of thermal cycling.

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QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONS

Thermal Aging and Thermal Cycle
Fiber Height per Channel

Figure 7 Boxplot of fiber height initial and after 1000 cycles of thermal cycling.

12QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONS

3.2 TWAL Test
The changes of IL and the absolute values of RL after TWAL test
are summarized in Table 5. IL TWAL test met the requirements ofmaximum IL change of 0.30dB. Only selected samples were tested toverify the mechanical strength after 2,000 hours of the thermal aging
at 105deg C. Table 5 summarizes the changes of IL and the absolutevalues of RL after TWAL test. The boxplot of maximum IL changes
under applied load at 1310nm and 1550nm are shown in Figure 8.
Observing, 90 degree loads typically affect the IL se performance
more and the results obtained are within the standard level.

Table 5 Insertion loss change summary under TWAL loads.

Measurement Taken
Under 0deg 0.49lbf

Under 90deg 0.49lbf

ItemMax

MinAve

StDev

Insertion Loss (dB) 1310nm

0.09

0.0

0.01

0.02

Insertion Loss (dB) 1550nm

0.07

0.0

0.011

0.02

Return Loss (dB) 1310nm

81.7

66.2

77.96

1.83

Return Loss (dB) 1550nm

82.0

67.2

78.79

2.05

Insertion Loss (dB) 1310nm

0.23

0.00.05

0.05

Insertion Loss (dB) 1550nm

0.24

0.00.05

0.05

Return Loss (dB) 1310nm

81.10

66.2

78.15

1.80

Return Loss (dB) 1550nm

81.60

67.1

78.86

2.01

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QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONSTWAL Test
TWAL Maximum Insertion Loss Change per Channel at 1310nm

TWAL Maximum Insertion Loss Change per Channel at 1550nm

Figure 8 Maximum insertion loss change per channel at 1310nm (top) and 1550nm (bottom) under applied load.

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QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONS

Summary and Future Work
The MPO connector assemblies were tested for thermal aging,thermal cycle and TWAL tests to verify the service life of MPO
connector under 105degC environment. The samples survived andpassed the test criteria without having significant performancechange or compromise. It provides a confidence that the Senko MPO
connector and the termination methods we used for CPO and OBO
of applications can withstand more sever temperature environment
than typical use cases now.

The study was focused on 105degC but for future work, there is aneed for further investigation of the higher temperature resistanceon optical connectors including MPO and other new connector types
such as SN-MT connector.

105oC
Thermal Aging

Thermal Cycle

MPO
Bayonet
MPO
Latch

TWAL

MPO Micro
Latch

MPO Family

MPO MiniFutureTesting

SN-MT Family

SN-MTStandard 2mm

NewConnectors

SN-MT Bare Ribbon
SN-MT Junior
SN-MT BTW15

QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONS

References
1. JESD22-A104F, Temperature cycling, published: Apr 2023, https://www.jedec.org/standards-documents/docs/jesd-22-a104e
2. JESD22-A103E.01, High temperature storage life, published: July 2021,
https://www.jedec.org/standards-documents/docs/jesd-22-a103d
3. GR-1435-Core, Generic Requirements for Multi-Fiber Optical Connectors, Issue :02, May 2008.
4.

C. Zimmel, “PON Deployment of Angle Polished Connectors: Endface Geometry and Connector Reliability in the Outside Plant,”
in Optical Fiber Communication Conference and Exposition and The National Fiber Optic Engineers Conference, Technical Digest(CD) (Optica Publishing Group, 2005), paper NTuF2.

5. R. Thongdaeng, S. Wangsan, T. Berdinskikh, R. Suurmann, J. M. Culbert and D. Hogberg, “Impact of thermal cycle on endface geometry of laser processed LC and standard LC connectors,” The 2012 11th International Conference on OpticalCommunications and Networks (ICOCN), Pattaya, Thailand, 2012, pp. 1-4, doi: 10.1109/ICOCN.2012.6486231.

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QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONS

Biography
Tiger Ninomiya is currently Sr. Technologist at SENKO Advanced Components. He is participating in the MSAs, Consortiums, and other Standard Setting Organizations, including TIA, IEC, IEEE, COBO and OIF. Within COBO, he served asa chairman of Co-Packaged Optics working group and Associate Director of Board of Director. He is currently a vicechair of TIA TR42.11 and a secretary of IEC TC 86 SC86B WG4. Tiger has been heavily involved in the development
and standardization of CS and SN connectors and is continuously innovating new products to further develop opticalconnectivity technology.

Tatiana Berdinskikh is the founder of Novophotonics Consulting Inc. She has 25+ years of experience in fiber optics,telecommunications, optoelectronics, and photonics. Tatiana is the Canadian Technical Expert for standards activitiesof IEC SC 86B, SC 86C, and a Chair of the Canadian Mirror Committee of SC 86B. She was a recipient of the IEC 1906
Award for contribution to the development of cleanliness specifications for fiber optic connectors. Tatiana chairs theiNEMI (International Electronics Manufacturing Initiatives) project “Development of the best practices for expanded
beam connectors in the data center applications”. She has co-authored over 50 journal publications and conference
papers in the field of optoelectronics and photonics, and the book “Degradation of Semiconductor Light-Emitting Diodes and Lasers”. Tatiana is a member of the Professional Engineers of Ontario.

Takeshi Kasai is a Technical Specialist at SENKO Advanced Components. He joined SENKO in 2019 and was transferred to Fiber Optics Division as a purchasing staff in Tokyo office in 2020. In 2021, Takeshi was transferred to Massachusetts where he helped development of VSFF connectors including SN-MT. He is currently representing SENKO insustainability division and is continuously innovating new products to further develop sustainable solutions for fiberconnectivity.

Jason Kim is a principal member of technical staff in Advanced silicon photonics packaging in GlobalFoundries. Heis currently responsible for component engineering and supply chain management of silicon photonic packaging andfiber solution. He is leading industry with passive alignment fiber solution including narrow pitch and high temperature.
He has over 25+ years in the semiconductor industry as technology and quality expert. He is CQE, CQA, CSQP and6sigma black belt as ASQ (American Society for Quality) Senior member.

Jae Kyu Cho is a Senior Member of Technical Staff within Advanced Silicon Packaging group at GLOBALFOUNDRIESin Malta, NY. Currently he serves as a project lead in packaging development projects and responsible for silicon
photonic packaging solutions and OSATs engagement. Before this role, he led various CMOS package development
projects, specializing in flip chip, wire bond and wafer level packaging. Prior to GLOBALFOUNDRIES, he worked asa FBEOL interconnect process development engineer at Intel and as advanced packaging material scientist at Dow
Electronic Materials. He received the B.S. and M.S. degrees from Seoul National University, South Korea and the Ph.D.
degree from Georgia Institute of Technology, Atlanta, GA, USA.

Norm Robson is currently a development manager in Advanced Silicon Photonics Packaging at GlobalFoundries. He
currently leads a team responsible for light-in/light-out of silicon photonic chips using GlobalFoundries FotonixTM Technology. Developing techniques for fiber attach to silicon, as well as on-board lasers and advanced materials. He has over25+ years in the semiconductor industry leading development teams for silicon photonics, 3D heterogeneous integration,embedded and stand-alone memory with IBM, Infineon Technologies, Siemens, and Marconi Electronic Device.

17QUALIFYING MPO CONNECTOR AT 105DEGC TO SUPPORT OBO, NPO AND CPO APPLICATIONS