Engineering Report CORELINK* Mechanical Splice 502-1190 12Jul05 Rev A 1. SCOPE This report describes testing performed on CORELINK* mechanical splices using Bellcore Specification TR-TSY-000765 (Splicing Systems For Singlemode Optical Fibers) as a guideline. All test were performed in house with the exception of vibration which was performed by Elite Electronics located in Franklin Park, Illinois. 2. OVERVIEW OF TESTING Specimens were exposed to: single mode insertion loss; multimode insertion loss; return loss; temperature cycling insertion loss; temperature cycling return loss; pull strength; water immersion; singlemode multiple insertion loss; vibration; and 900 micron torsion test. 2.1. Insertion Loss, Single Mode A. Test Equipment and Conditions Tests were performed by laboratory technicians under laboratory conditions. Splice loss tests were performed using the power method as defined in EIA RS-455-34. See Figure 1 for test setup. Tests were performed at 1300 nm wavelength using a Siecor CME-1000 fiber optic attenuation test set. Temperature and humidity were normal ambient conditions. Two different fiber types were used: Corning singlemode fiber SMF-28 with CPC-3 coating (mode field diameter of 9.5 microns); and AT&T depressed cladding type fiber (mode field diameter of 8.7 microns). Cleaving was performed using a Fujikura CT-07BS cleaver. Figure 1 Singlemode Insertion Loss Test Setup - Similar and Dissimilar Fibers B. Insertion Loss, Identical Fibers 1. From a supply of 100 splices, 26 splices were randomly selected and tested. The system was setup with a direct fiber connection between the source and detector and an initial power reading taken. The fiber was then broken and the first insertion loss was recorded for each splice using the same fiber. Splices were made per Reliable Specification RLEC 633-100-004 (CORELINK Fiber Optic Mechanical Splice Description and Installation). Loss was calculated using the initial power reading and the power reading after splicing using the following formula: db = 10Log 10 (P 2 /P 1 ) Where: P 1 = initial power reading P 2 = power reading after splice 2005 Tyco Electronics Corporation Harrisburg, PA All International Rights Reserved * Trademark 1 of 11 Indicates change LOC B
2. Test Results Splice losses were as follows: 9 splices <.050 db 12 splices >.050 db <.100 db 4 splices >.100 db <.150 db 1 splice >.150 db <.200 db See Figure 2 for histogram plot of these results which represent a mean splice loss of.057 db with a standard deviation of.025 db. Out of this test group, 96% of the splices were below.125 db. C. Insertion Loss, Dissimilar Fibers Figure 2 Singlemode Insertion Loss 1. Six new splices were selected and tested for splice loss for a total of 19 data points using the fibers described above. The source and detector were switched and 19 more data points were recorded. The data points represent a combination of first and multiple insertions. Multiple insertions were made by removing and replacing one of the two fibers in the splice. See Figure 1 for test setup. Splices were made per RLEC 633-100-004. Power readings were obtained and calculated per the procedures in paragraph 2.1.B. 2. Test Results Loss measurements for AT&T to Corning fiber were as follows: 2 splices >.050 db <.100 db 5 splices >.100 db <.150 db 8 splices >.150 db <.200 db 4 splices >.200 db <.300 db Rev A 2 of 11
Loss measurements for Corning to AT&T fiber were as follows: 2 splices >.025 db <.050 db 3 splices >.050 db <.100 db 5 splices >.100 db <.150 db 4 splices >.150 db <.200 db 5 splices >.200 db <.300 db The theoretical nominal intrinsic loss for these two fibers is.034 db. This data represents for AT&T to Corning, an average loss of.108 db with 90% less than.22 db; and for Corning to AT&T, and average loss of.127 db with 90% less than.21 db. The intrinsic loss has been subtracted from the above data to obtain the averages. 2.2. Insertion Loss, Multimode Fiber A. Test Equipment and Conditions Test conditions were the same as those in paragraph 2.1.A. Tests were performed at 1300 nm wavelength using a General Fiber Optics series 91-2000 LED source and a 3M Photodyne 22LXC dual channel fiber optic multimeter. The fiber used was Berk-Tek duplex jumper cable with a mode field diameter of 62.5 microns. Cleaving was performed using a Fujikura CT-07BS cleaver. B. Insertion Loss Insertion loss tests for multimode fiber were performed in two different ways. In the first test, five first insertion were performed by concatenating the splices and measuring the loss after each splice. The second test involved multiple insertions on a single splice. Twenty splices were performed. See Figure 3 for test setup. Power readings were obtained using the same methods described in paragraph 2.1.B. with loss calculated using the formula also in paragraph 2.1.B. 1. First test results were as follows: Splice 1.00 db Splice 2.00 db Splice 3.01 db Splice 4.01 db Splice 5.01 db Figure 3 Multimode Insertion Loss Test Setup This represents a mean splice loss per splice of.002 db. Rev A 3 of 11
2. The second test results can be summarized as after 20 insertions, the insertion loss for each insertion varied between.00 db and.03 db. 2.3. Return Loss, Singlemode A. Test Equipment and Conditions Test conditions were the same as those in paragraph 2.1.A. See Figure 4 for test setup. Source used was a 3M Photodyne 1300 nm, 1700 series laser optical source driver, Model 9XT. Fiber used was Corning SMF-28. Couplers used were Amphenol Model 206-11101. B. Return Loss Figure 4 Return Loss Test Setup A total of 16 splices were tested for first insertion return loss. To establish an initial power reading, a measurement was taken on a bare fiber ending in gel. The loss measurements were then made by breaking the fiber and making 16 first insertion splices with the same fiber setup. Return loss was then calculated using the following formula: db = 10Log 10 (P r /P i ) Where: P r = reflected power reading P i = incident optical power The initial zero reading was 52 db. The first insertion results are as follows: Splice Number Return Loss (db) Splice Number Return Loss (db) 42 50 50 46 43 46 51 49 44 47 52 49 45 52 53 49 46 47 54 46 47 54 55 46 48 52 56 51 49 45 57 46 This data can be summarized as having an average return loss of 48.4 db with a standard deviation of 3.81 db. Rev A 4 of 11
2.4. Temperature Cycling Insertion Loss A. Test Equipment and Conditions Temperature chamber was a Thermotron. Source, fiber and couplers were the same as in paragraph 2.3.A. Detector was the same as in paragraph 2.2.A. Chart recorder was a Gould strip recorder. See Figure 5 for test setup. B. Temperature Cycling Figure 5 Temperature Cycling Insertion Loss Test Setup Splices were subjected to 100 temperature cycles between -40 and 80/C with the rate of change at 1/C per minute and uncontrolled humidity. See Figure 6 for profile of temperature change as a function of time. Temperature and insertion loss were continuously monitored by a normalizing circuit and a continuous strip chart. Rev A 5 of 11
Figure 6 Temperature Cycling Profile Splice loss did not exceed.07 db variation from the initial reading at any point in the test. See Figure 7 for sample of the recording. Figure 7 Temperature Cycling Sample Rev A 6 of 11
2.5. Temperature Cycling Return Loss A. Test Equipment and Conditions Equipment used was the same as that used in paragraph 2.4.A.. See Figure 8 for test setup. B. Temperature Cycling Figure 8 Temperature Cycling Return Loss Test Setup Splices were subjected to 20 temperature cycles between -40 and 80/C with the rate of change at 1/C per minute and uncontrolled humidity. See Figure 6 for profile of temperature change as a function of time. Temperature and return loss were continuously monitored by a normalizing circuit and a continuous strip chart. 2.6. Pull Strength Testing showed that no point between -30 and 80/C did the return loss go below 50 db. Between -30 and -40/C, the return loss did not go below 40 db. A. Test Conditions and Equipment Test conditions and equipment was the same as that used in paragraph 2.1.A.. See Figure 9 for test setup. A Tinius Olsen Series 1000 tensile tester was used for pulling the fibers and reading force with a 100 pound load cell with a minimum load range of 5 pounds maximum scale. Loss versus load was plotted on a Tinius Olsen Series 1000 X-Y recorder. Rev A 7 of 11
Figure 9 Pull Strength Test Setup B. Pull Strength A total of 21 splices were made per RLEC 633-100-004. A clamping mechanism was installed in the clamps of the pull tester that did not induce loss due to the clamp force applied to the fiber. Splices were made and an initial loss measurement taken. Fibers were then pulled at a rate of 1 inch per minute. Force versus loss was plotted, the point on the curve at which the loss increased was then recorded as the pull strength of the splice. 2.7. Water Immersion Pull Force (lb) Number of Splices >.5 <.75 1 >.75 <.875 1 >.875 < 1.0 4 > 1.0 < 1.125 5 > 1.125 < 1.25 6 > 1.25 < 1.375 3 > 1.375 < 1.5 1 This data represents a mean pull force of 1.09 pound with a standard deviation of.185 pound. A. Test Conditions and Equipment Test conditions and equipment was the same as that used in paragraph 2.4.A. with the exception that the splice was immersed in water in a container placed in the temperature chamber stabilized at 43/C. Splices were made per RLEC 633-100-004. Rev A 8 of 11
B. Water Immersion The splice was made and insertion loss recorded. The splice was then placed in the temperature chamber and insertion loss was again recorded after the water stabilized to the chamber temperature. The splice remained in the temperature chamber for five days. The splice loss was again measured before removing the splice from the temperature chamber at the end of the five day period. Insertion loss was recorded continuously throughout the five day period. At the end of 24 hours and at the end of the five day period, the splice loss did not change from the initial reading taken before the splice was immersed in water. 2.8. Multiple Insertion A. Test Conditions and Equipment Test conditions and equipment was the same as that used in paragraph 2.1.A. See Figure 1 for test setup. B. Multiple Insertion Loss A total of 19 splices were randomly selected from a lot of 100 splices. Ten insertion loss measurements were made on each splice and recorded. Multiple insertion was made by opening the splice and removing and replacing one fiber. The fibers were always kept in the same angular orientation throughout the multiple insertions for each splice. Results can be summarized as the splice having 89% of the loss measurements below.2 db. See Figure 10 for a plot of the loss measurements. Rev A 9 of 11
Figure 10 2.9. Vibration A. Test Conditions and Equipment Test was performed at room temperature. Source and detector was a Siecor CME-1000 attenuation test set. The vibration machine was an MB Model EL3600 with amplifier MB Model T451, Type 2 and control console HP Model 5427A. The accelerometer was Endevco Model 2233E. Splices were made per RLEC 633-100-004. See Figure 11 for test setup. Rev A 10 of 11
Figure 11 Vibration Test Setup B. Vibration Six splices were secured to a fixture which in turn was rigidly attached to the moving element of the vibration machine. Splices were concatenated and splice loss was monitored during the test. Splices were vibrated in each of three mutually perpendicular axes over the frequency range of 10 to 55 Hz at a constant vibratory amplitude of 1.52 mm DA. Frequency range was traversed in one minute and was repeated 20 times in each axis. The change in splice loss did not change more than.05 db during the entire test. 2.10. Torsional Stress Resistance A. Test Conditions and Equipment Test conditions and equipment was the same as that used in paragraph 2.4.A. with the exception that six concatenated splices were used in place of a single splice. Splices were made per RLEC 633-100-004. Fiber used was AT&T 900 micron. B. Torsional Stress Splice was made with 60 inches of fiber extending from both ends of the splice. These ends were secured to a splice tray and crossed over and figure eighted five times and stored on the tray. Splices were stored for seven days at room temperature and then placed in a temperature chamber and cycled per a standard twelve hour cycle for a total of 50 cycles. Splice loss was continuously recorded while temperature cycling the splice. Visual examination showed no evidence of physical damage with all fibers intact and not broken. The concatenated splice loss, which is the sum of insertion loss values for six splices, did not vary more than.3 db. Therefore, the average splice loss did not vary more than.05 db. Rev A 11 of 11