1、- _ - IND-STD ANSIIEIA 455-L79 -88 NOTICE L LO m 9999998 0004754 m ADOPTION NOTICE 1 . 14 February 1991 for ANSI/EIA-455-179-88 4 February 1988 ANSI/EIA-455-179-88 was adopted on Department of Defense (DoD), The indicated industry group has furnished the clearance required by existing regulations. t
2、he DoD Single Stock Point, Naval Publications and Forms Center, 5801 Tabor Avenue, Fhiladelphia, FA 19120, for issue to DoD activities only. All other requestors must obtain documents from: 14 February 1991 and is approved for use by the Copies of the document are stocked by The Electronic Industrie
3、s Association 2001 Eye Street, NW Washington, DC 20006 Title of Document: Inspection of Cleaved Fiber End Faces by Interferometry Date of Specific Issue Adopted: 4 February 1988 Releasing Non-Government Standards Body: The Electronics Industries Association I Acceptance o this FOTP does not imply th
4、at referenced FOTPs have been accepted. . . -. . - - NOTICE: When reaffirmation, amendment, revision, or cancellation of this standard is initially proposed, the industry group responsible for this standard shall inform the military coordinating activity of the proposed change and request part i cip
5、ation. Custodians: Army - Ci Navy - AS Air Force - 85 Review activities: Army - TE Navy - EC, MC, SH Air Force - 11, 17, 19, 80, 90, 99 DLA - ES GSA - FSS OUSD - SD Military Coordinating Activity: Army - CR Agent: DLA - ES (Project 60GP-0196-9) User activities: kir Force - 1.3, 14 Allm N/A FSC 60GP
6、DISTRIBUTION STATEMENT: Approved tor public release; distribution is unlimited. Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-h- - - - EIA 455-179 88 = 3234600 O069656 O ,., I
7、p 5+ the intent of this method shall not be confused with the intent of FOTP-57 (EIA-455-57), “Optical Fiber End Preparation and Examination“, which is more concerned with the absolute results on particular fiber end(s) than with a comparison of relative results. The device used for this method of c
8、omparison is an incident-light interference device (Interferometer). 2. TEST EQUIFMENT 2.1 Microscope A microscope equipped with an incident-light interferometer. A Z-axis measuring facility is desirable for the measurement of certain fiber end-face conditions. 2.1.1 Resolution Resolution shall be s
9、ufficient to distinguish an Interference pattern of 250 lines per millimeter (this is the approximation of a 4 degree angle). 2.1.2 Light Source The light source shall be monochromatic and collimated (e.g., a helium-neon coherent source) or shall be equipped with an interference filter with a known
10、central wavelength (eg., 546 nanometer green filter). Spectral width shall be 10 nanometers. 2.1.3 Fixturing A fiber-holding fixture, e.g. a vacuum chuck, shall be securely afxed to the object stage of the microscope. It shall be positioned to center the fiber end face in the microscopes field of vi
11、ew and to align the fiber axis with the optical axis of the microscope. The fixture shall allow rotation of the fiber for calibration and alignment purposes. 2.1.4 Light Interference Device An incident light interference device shall be attached to or installed in the microscope. The interference de
12、vice shall be capable of delineating topographical features to an accuracy of 2 milliradians (1/8 of a degree) within the range of O to 4 2.2 TV Monitor The TV monitor shall have a 38 cm (15 inch) screen (measured diagonally) with a minimum resolution of 400 lines and a geometric linearity of 3% ove
13、rall unless otherwise specified in the Detail Specification. from an ideal (perpendicular) fiber end face. Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EIA 455-177 88 3234600
14、 OObSbbL 4 EM-455-179 Page 2 2.3 Measuring Scale A 15 cm (6 inches) scale graduated with minimum scale divisions of 1.6 mm (.O62 in). 3. TEST SAMPLES The required number of prepared fibers shall be specified in the Detail Specification. 4. TEST PROCEDURE 4.1 Test Description Interferometry provides
15、a means for making an accurate examination of a cleaved fiber end. An interferometer picture of a fiber end surface is a contour map with each contour line (fringe) representing a difference in elevation of the fiber surface. A detailed description of interferometry is attached as Appendix A. 4.2 Te
16、st Conditions Unless otherwise specified in the Detail Specifieation, tests shall be performed under standard atmospheric conditions of EIA-455, Para. 4, (25 C (77 OF) f5 C, and 30-60% relative humidity). 4.3 Equipment Calibration To ensure accurate angular measurement of the fiber end face, it is n
17、ecessary to first calibrate the squareness of the vacuum chuck (used for holding the fiber) relative to the optical light path of the interferometer, in accordance with equipment manufacturers instructions. The correct calibration of the vacuum chuck can be verified by the following procedure. 1. Pl
18、ace a master reference fiber with a known cleave angle (eg. 1 degree) into the vacuum chuck fixture. FOCUS on the fiber end face surface to confirm that interference pattern generated by the cleave angle of the reference fiber is correct in relation to the known cleave angle. If it is not, reinsert
19、the fiber in the fixture to ensure proper alignment. 3. Rotate the reference fiber by hand through one complete revolution (360”) observing the interference pattern at approximately 90 intervals. The 90 increments can easily be approximated by attaching a paper tab to the end of the fiber to serve a
20、s a flag indicator. The focus of the fiber end face surface will require readjustment as required at each inspection point. The increase or decrease in the total number of fringes (dark bands) observed shall not exceed a change of 1 fringe (equivalent to 1/8 for a 125 pm fiber), unless otherwise spe
21、cified in the Detail Specification. 5. If the verification check using the reference fiber does not meet the specified angularity requirement, Le., fl fringe, the next step is to carefully clean the locating surfaces of the vacuum chuck to remove any foreign particles that may cause the reference fi
22、ber to be misaligned. Repeat the 360 revolution of the reference fiber as stated in step 4 above. If the fiber again fails to meet the required angularity, repeat the entire process of rechecking the squareness of the vacuum chuck, followed by the verification procedure with the reference fiber. 2.
23、4. 4.4 Test Specimen Examination Place the cleaved test fiber in the vacuum chuck and view the interferometric pattern with the microscope eyepiece or on a remote TV terminal display. After observing the pattern of the fiber end face, proceed to characterize the condition of the end face with the ai
24、d of Figure II and Figures 6 - 14 in Appendix A which illustrates various surface irregularities. It should be emphasized that the illustrations shown in Appendix A are intended only to assist the user in identifying a particular type of Copyright Telecommunications Industry Association Provided by
25、IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,- EIA 455-L9 B 3234b00 0069bb2 b - EIA-45 5- 179 Page 3 surface defect. The illustrations are not intended to constitute visual standards, against which similar defects are compared. 4.4.1 Met
26、hod of Measurement The purpose in establishing a method for the surface measurement of a cleaved angle or a defect area is to aid in classifying the magnitude of the defect or characterizing the end angle resulting from a cleaving operation. The measurement information is intended to be used in conj
27、unction with the calculated angle of the cleaved fiber and the defect description outlined in Sections 4.4.2 and 4.4.3. It should be noted that the usage of this information and data is solely dependent on the type of criteria established by the Detail Specification for evaluating cleaver performanc
28、e. 4.4.1.1 Procedure for Measurement i. Locate the cleaved fiber in the vacuum chuck mounted on the stage of the microscope equipped with an incident-light interferometer. 2. Display the fiber end face on the TV monitor connected to the microscope. Using the magnification facility of the microscope,
29、 enlarge the image of the fiber end face to approximately 16.5 cm (6.5 in). The magnification of the fiber end face from 125 pm (.O05 in) to 16.5 cm (6.5 in) is equivalent to an increase in size of 1300 times. Based on this magnified fiber surface, the following approximate ratio of microns to centi
30、meters or inches is established for a 125 pm diameter fiber. 3. 2.54 cm (1 in) = 19 pm 1.27 cm (.5 in) = 9 pm .63 cm (.25 in) = 5 pm .32 cm (.125 in) = 2.5 pm .16 cm (.O62 in) = 1 pm 4. The extent of the defect area in relation to the fiber core shall be measured directly on the TV screen using a sc
31、ale with a minimum scale division of 1/16 inch. Based on this scale division, a particular dimension is capable of being measured within a 1 ,um accuracy. The “X“ and “Y“ dimensions shown in Figure I illustrates the ability to measure both the distance across the fiber end angle, shown as “XI, and t
32、he distance of the defect, shown as “Y“ in relation to the core of the fiber. The “X“ dimension is measured by establishing a line through the center of the magnified fiber end with a scale. The line which crosses the greatest number of fringes within the area bounded by the fiber diameter shall be
33、designated as the %“ dimension. The “Y“, or defect area dimension, is measured by selecting the particular width or length under consideration and measuring the dimension directly as it appears on the screen using a scale. 5. 4.4.2 Measuring Fiber End Angularity The determination of the end face ang
34、le for a cleaved fiber surface is based on the formulas shown below. For a cleaved surface with an end angle and a defect area as illustrated in Figure I, the fiber end angle is calculated by the following formula: A. where: e = cleave angle of fiber end Copyright Telecommunications Industry Associa
35、tion Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-r EIA 455-179 88 m 3234b00 00b7bb3 8 m Ea-45 5- 17 9 Page 4 Number of Fringes Fiber Diameter in pm Measured Distance (see Section 4.4.1) of the greatest fringe density in pm,
36、 determined by drawing a line through the center of the fiber end which crosses the greatest number of fringes within the measured area. Number of Fringes per degree N is calculated by the formula D N = .O349 - x where: D = Fiber diameter in pm X = Light source wavelength in pm Example: Using the da
37、ta furnished in Figure I the cleaved angle, 8, is calculated as follows: B. For an ideal surface with no defects, X is equal to the fiber diameter; therefore, the cleaved fiber end angle is determined by the formula: 4.4.3 Defect Conditions and Their Measurement 4.4.3.1 Indent The indent or scribing
38、 mark is the intentionally introduced flaw in the fiber from which the controlled fracture (cleave) propagates. An effective indent will have smooth, definable- borders and a minimal depth. See Figure 6. The depth of the indent (into the fiber diameter) shall be measured using the technique specifie
39、d in Section 4.4.1 unless otherwise specified in the Detail Specification. 4.4.3.2 Lip/Rolloff A lip is a sharp protrusion from the edge of a cleaved fiber. Excessive lip height is conducive to ber damage. See Figure 7. Rolloff is the opposite condition of lipping. Also known as breakover, it is the
40、 rounding-off of the edge of a cleaved fiber. Excessive rolloff can cause high insertion or splice losses. See Figure 8. Unless otherwise specified in the Detail Specification the width of a lip or rolloff shall be measured starting at a point where the angle of the fiber end face exceeds approximat
41、ely 10 ? (see Section 4.4.1). I The height of a lip or the depth of the rolloff (breakover) shall be measured using the Z axis facility of the microscope. Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted wit
42、hout license from IHS-,-,-EIA 455-179 8 W 3234b00 00b9bb4 T W EN-455-179 Page 5 The measurement process is as follows: i. Focus on one edge of the fiber opposite the lip or rolloff. Move across the fiber the known distance, to the point where the fiber end face angle exceeds 10 O. The method of dete
43、rmining this distance is specified in Section 4.4.1. The distance moved is confirmed by observing the digital readout on the display unit. Refocus on the fiber surface at this point and note the 2 axis measurement on the appropriate readout unit. 2. Next, continue moving across the fiber to the oppo
44、site edge where the lip or rolloff terminates. Refocus on this point and again note the 2 axis measurement on the readout unit. The difference in the readings of steps 1 and 2 reflect the displacement of the Z axis and therefore the vertical measurement. The direction of the displacement will identi
45、fy the condition as a lip or a rolloff. 4.4.3.3 Chip Chips are localized fractures or breaks on the end of a cleaved fiber. Their significance depends on their size and location. See Figure 9. The width of the chip across the surface of the fiber shall be measured using the technique specified in Se
46、ction 4.4.1 unless otherwise specified in the Detail Specification. 4.4.3.4 Hacklemist Hackle and Mist are both forms of surface irregularities occurring during the cleave. Hackle is a severe surface aberration, very detrimental to light transmission, while mist is a less severe manifestation of sur
47、face irregularity. See Figure 10. The defect condition shall be identified as hackle and/or mist and the area(s) shall be approximated as a percentage of the total fiber end face surface. Secondly, the location of the defect area relative to the core shall be measured and noted using the technique c
48、ited in Section 4.4.1. 4.4.3.5 Spiral Spirals are end-face conditions which feature abrupt changes in the surface topology. Their impact on connectors and splices are application dependent. See Figure 11. A defect area of a spiral condition is measured by determining the distance that the focus area
49、, from which the spiral fringes radiate, penetrates from the outer edge of the fiber towards the center. The width that the focus area extends inward towards the core from the fiber edge shall be measured using the technique specified in Section 4.4.1 unless otherwise specified in the Detail Specification. 4.4.3.6 Step A step is an abrupt change in the topology of a fiber end face surface. The impact of such a condition on connectors and mechanized splices is application dependent. S
