# Are 3M Hot Melt Fiber Connector As Reliable As Standard Epoxy and Polish Fiber Connectors?

If you have been in the fiber optic communication industry for a while, you must be familiar with the tried and true, traditional style epoxy, cure and polish fiber optic connectors – may it be FC, SC, ST, LC or MTRJ.

Those epoxy and polish connectors are reliable, cheap and has been industry standardized. Big manufacturers terminate thousands or even tens of thousands of epoxy and polish connectors each day.

However, these standard connectors are not suitable for all applications, especially in the field. Emergency recovery and low quantity field terminations require quick and easy approaches for fiber optic connector termination. That is where the quick termination connectors such as 3M Hot Melt, 3M Crimplok, Corning Unicam, Tyco/AMP Lightcrimp Plus and the newly introduced 3M No Polish connectors come to play.

What characteristics do these quick termination connectors have in common? Quick, low tool cost and easy to master. Although each type has its own design characteristics, quick and easy are what make them different from the traditional epoxy and polish fiber connectors.

Traditional connectors cost as low as 2 bucks each while the quick termination connectors typical cost from $7 and above. But traditional connectors require polishing machines that cost$5000 or even more, while quick termination connectors only require tools that cost less than \$1500 or even only hundreds of dollars.

However, the big concern most fiber optic technicians and engineers have is whether they provide the same long term reliability, low insertion loss and back reflection as the good old epoxy and polish connectors. That is what this article is all about.

We are presenting the 3M Hot Melt connector reliability technical report here. This is the first in a series of reliability report on quick termination connectors. Keep tuned and we will follow this with reports on 3M Crimplok, Corning Unicam, Tyco/AMP Lightcrimp Plus and 3M No Polish connectors.

The Conclusion?

3M Hot Melt fiber optic connectors meet targeted requirements.

The test results showed consistent low insertion loss, environmental stability and physical robustness of 3M Hot Melt connectors. When properly installed, the connector provides a reliable voice and/or data transmission circuit.

A series of optical, environmental and mechanical tests were conducted which exposes them to conditions more severe than those anticipated in actual use. The tests were in accordance with TIA-568.

Four groups of new 3M Hot Melt ST connectors were tested. Here is the test setup.

 New Product Environmental Mechanical Mechanical Environmental (Extended Temp.) New Product (30 pcs) Group 0 (10 pcs) Group 1 (10 pcs) Group 2 (10 pcs) Group 3 (10 pcs) Low Temperature Storage (10 each, -10°C) Impact (10 each) Connector Durability (10 each) Extended Low Temperature Storage (10 each, -40°C) High Temperature Storage(10 each, 60°C) Flex (10 each) Extended High Temperature Storage(10 each, 85°C) Humidity (10 each, 40°C, 90~95% RH) Twist (10 each) Extended Humidity (10 each, 85°C, 95% RH) Cable Retention (10 each)

1. New Product Test Result

30 pcs of 3M Hot Melt ST connectors were cleaned and tested under room temperature 22°C. Their insertion loss and back reflection were recorded as below.

 Insertion Loss (dB) Back Reflection (dB) Wavelength Mean Standard Deviation Mean Standard Deviation 850 nm 0.10 0.04 -27.03 0.74 1310nm 0.11 0.06 -28.92 1.42

2. Environmental Test (Group 0)

2.1 Low Temperature Storage Test (10 samples, -10°C)

The 10 samples were put in a -10°C chamber for 96 hours. Insertion loss and back reflection were tested at the start and finish at 22°C.

Insertion Loss Test Result

 Wavelength (nm) Mean@Start (dB) Std. Dev.@Start (dB) Mean@In Process (dB) Std. Dev.@In Process (db) Mean@Finish (db) Std. Dev.@Finish (dB) 830 0.10 0.04 0.13 0.04 0.09 0.04 1310 0.11 0.06 0.14 0.06 0.09 0.06

Back Reflection Test Result

 Wavelength Mean@Start (dB) Std. Dev.@Start (dB) Mean@In Process (dB) Std. Dev.@In Process (dB) Mean@Finish (dB) Std. Dev.@Finish (dB) 830 -27.03 0.74 -27.18 0.68 -27.00 0.70 1310 -28.92 1.42 -28.96 1.34 -28.87 1.40

2.2 High Temperature Storage Test (10 samples, 60°C)

Those 10 samples, after finishing the cold test from above, were then put into a 60°C chamber for 336 hours storage. Measurements were made at the start, in the process and at finish.

Insertion Loss Test Result

 Wavelength (nm) Mean@Start (dB) Std. Dev.@Start (dB) Mean@In Process (dB) Std. Dev.@In Process (db) Mean@Finish (db) Std. Dev.@Finish (dB) 830 0.09 0.04 0.08 0.05 0.10 0.05 1310 0.09 0.06 0.08 0.06 0.10 0.07

Back Reflection Test Result

 Wavelength Mean@Start (dB) Std. Dev.@Start (dB) Mean@In Process (dB) Std. Dev.@In Process (dB) Mean@Finish (dB) Std. Dev.@Finish (dB) 830 -27.02 0.70 -26.08 1.25 -26.86 1.00 1310 -28.87 1.40 -28.15 1.61 -28.72 1.54

2.3 Humidity Test (10 samples, 40°C, 90~95% Relative Humidity)

Those 10 samples, after finishing the temperature life test from above, were then put into a 40°C, 90-95% Relative Humidity chamber for 96 hours.

Insertion Loss Test Result

 Wavelength (nm) Mean@Start (dB) Std. Dev.@Start (dB) Mean@In Process (dB) Std. Dev.@In Process (db) Mean@Finish (db) Std. Dev.@Finish (dB) 830 0.09 0.05 0.09 0.04 0.08 0.04 1310 0.10 0.07 0.09 0.05 0.09 0.06

Back Reflection Test Result

 Wavelength Mean@Start (dB) Std. Dev.@Start (dB) Mean@In Process (dB) Std. Dev.@In Process (dB) Mean@Finish (dB) Std. Dev.@Finish (dB) 830 -26.85 1.00 -26.72 1.00 -27.12 0.85 1310 -28.76 1.53 -28.67 1.48 -28.89 1.49

3. Mechanical Test (Group 1)

3.1 Impact Test (10 samples)

10 pcs of 3M Hot Melt ST connectors were fixed in a impact test fixture. These connectors were then raised to the horizontal position and released to strike a concrete block. The impact was repeated 8 times and then the connectors were tested.

Test Results After Impact

 Insertion Loss (dB) Back Reflection (dB) Wavelength Mean Standard Deviation Mean Standard Deviation 850 nm 0.13 0.05 -28.13 0.54 1310nm 0.05 0.03 -25.65 0.91

3.2 Flex Test (10 Samples)

Those 10 connector samples, after finishing the above impact test, were fixed onto the swing arm of 3M Flex Tester. A 0.5kg load is attached to the cable 25cm from the pivot point. The connector is then cycled through 0°, +90°, 0°, -90°, 0°, about the center axis of the connector for 100 cycles. Measurements were taken after the flex test.

Test Results After Flex Test

 Insertion Loss (dB) Back Reflection (dB) Wavelength Mean Standard Deviation Mean Standard Deviation 850 nm 0.10 0.04 -23.12 0.49 1310nm 0.05 0.02 -25.68 0.87

3.3 Twist Test (10 Samples)

Those 10 connector samples, after finishing the above Flex test, were fixed to the swing arm of the 3M Flex tester and the swing arm is locked in the 0° position. A 15N (3.3lbs) load is attached to the cable 25cm from the pivot point. The weight is rotated about the cable axis 2.5 revolutions in one direction, reversed for 5 revolutions, and reversed for 5 more revolution for a total of 10 cycles.

Test Results After Twist Test

 Insertion Loss (dB) Back Reflection (dB) Wavelength Mean Standard Deviation Mean Standard Deviation 850 nm 0.11 0.04 -23.13 0.46 1310nm 0.04 0.03 -25.63 0.95

3.4 Cable Retention Test (10 Samples)

Testing was performed on samples subjected to Twist test. A coupling was secured to the traversing stage of an Instron tensile tester. At 0.3m from the coupling – connector, the cable was secured to the stationary base by wrapping the cable 3 times around a 3″ mandrel. A load of 15 lbs. @ 0° is applied to the connector for 5 seconds, then released. Additional testing was performed after the first cable Retention Test in the same manner, but with 4.4 lbs. @ 90°. Values for insertion loss and reflection are measured 10 seconds after releasing the load.

Test Results After Cable Retention Test

 Insertion Loss (dB) Back Reflection (dB) Wavelength Mean Standard Deviation Mean Standard Deviation 850 nm 0.12 0.05 -22.98 0.62 1310nm 0.04 0.04 -25.57 0.99

4. Mechanical Test (Group 2)

4.1 Connector Durability

10 pcs of 3M Hot Melt ST connectors were tested for connector durability. One side of each connector was removed and inserted 500 times. Each connector was cleaned and tested every 25th insertion.

Test Results After Connector Durability Test

 Insertion Loss (dB) Back Reflection (dB) Wavelength Mean Standard Deviation Mean Standard Deviation 850 nm 0.17 0.04 -23.09 0.52 1310nm 0.17 0.06 -26.29 0.48

5. Environmental Test (with extended temperature range, Group 3)

5.1 Extended Low Temperature Storage Test (10 Samples, -40°C)

10 pcs of 3M Hot Melt ST fiber optic connectors were put in a -40°C chamber for 96 hours.

Test Results After Extended Low Temperature Storage

 Insertion Loss (dB) Back Reflection (dB) Wavelength Mean Standard Deviation Mean Standard Deviation 850 nm 0.09 0.03 -29.29 1.68 1310nm 0.07 0.03 -25.09 1.51

5.2 Extended High Temperature Storage Test (10 Samples, 85°C)

Those 10 connector samples, after finishing the above extended low temperature storage test, were put in a 85°C chamber for 96 hours.

Test Results After Extended High Temperature Storage

 Insertion Loss (dB) Back Reflection (dB) Wavelength Mean Standard Deviation Mean Standard Deviation 850 nm 0.08 0.04 -25.00 1.56 1310nm 0.08 0.03 -29.21 1.82

5.3 Extended Humidity Test (10 Samples, 85°C, 95% Relative Humidity)

Those 10 connector samples, after finishing the above extended high temperature storage test, were put in a 85°C, 95% relative humidity chamber for 96 hours.

Test Results After Extended Humidity Storage Test

 Insertion Loss (dB) Back Reflection (dB) Wavelength Mean Standard Deviation Mean Standard Deviation 850 nm 0.10 0.03 -25.32 1.56 1310nm 0.07 0.03 -29.36 1.82

P.S.

3M Hot Melt fiber optic connectors proved that they can provide high repeatability and low insertion loss for premises network, LAN and telco applications. The typical less than 2 minutes field termination for multiple connectors increases productivity significantly.