1、ADOPTION NOTICE I - - 17 March 1989 For ANSI/EIA-455-174-88 6 July 1988 AHSI/ETA-455-174-88 was adopted on , and is approved tor uee by the Department of Defense (DoD). The indicated industry group has iurniahed the clearance required by existing regulations. the DoD Single Stock Point, Naval Public
2、ations and Farm Center, 5801 Tabor Avenue, Philadelphia, PA 19120, or issue to ZaD activities only. All other requestors must obtain documents from: l7 Iarch O8 Copies of the -document are stocked by The Electronic! Industries Association 2001 Eye Street, NW -I - _. - - - .? _. - -= Washington, DC 2
3、0006 - Title of Document: Mode Field Diameter of Single-Mode Optical Fiber by Knife-Edge Scanning in the Far Field Date of Specific Issue: 6 July, 1988 Releasing Non-Government Standards Body: The Electronics Industries Association Acceptance of this FOTP does not imply that referenced FOTPs have be
4、en 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 participation. .- - - -*- T- -E Custodians: Army
5、 - CB Navy - AS Air Force - 05 Review act iv i t i ea : Army - TE Navy - EC, Mc, SH AiF Force - 11, 17, lQ, 80, 00, QQ DLA - ES QSA - FSS. OUSD - S-D + Military Coordinating Activity: Army - CE Agent: DLA - ES (Pro j ec t 6OP-O 1931 use activities: -. - Air Force - 13, 14 . AVSC NIA P FSC 60QP THIS
6、DOCUMENT CONTAINS 1 PAGES. -_ - -_=, - -_-_ DISTRIBUTION STATEMENT: Approved for public release: distribution is unlimited. Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,- u EIA 455-174
7、 2575522 8054540 b EIA STANDARD 18-03 ANSI/ EM-455-174-88 APPROVED: July 6, 1888 FOTP-174 Mode Field Diameter of Single-Mode Optical Fiber by Knife-Edge Scanning in the Far Field EIA-455-174 SEPTEMBER 1988 ELCTRONIC INDUSTRIES ASSOCIATION ENGINEERING DEPARTMENT Copyright Electronic Industries Allian
8、ce Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,- EIA 455-174 B O 25755312 0054541 H NOTICE EIA Engineering Standards and Publications are designed to serve the public interest through eliminating misunderstandings between ma
9、nufacturers and purchasers, facilitating interchangeability and improvement of prducts, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence of such Standards and Pub- lications shall not in any respect preclude any member or
10、 non-member of EIA from manufacturing or selling products not conforming to such Standards and Publications, nor shall the existence of such Standards and Publications preclude their voluntary use by those other than EIA members, whether the standard is to be used either domestically or internationa
11、lly. Recommended Standards and Publications are adopted by EIA without regard to whether or not their adoption may involve patents on articles, materials, or processes. By such action, EIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopti
12、ng the Recom- mended Standard or Publication. (From EIA Standards Proposal No. 1861, formulated under the cognizance of the EIA FO-6.6 Subcommittee on Fibers and Materials,) Published by ELECTRONIC INDUSTRIES ASSOCIATION Engineering Department 2001 Eye Street, N.W. Washington, D.C. 20006 Copyright 1
13、988 PRCE: $10.00, Published in U.S.A. Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EIA-455-174 Page 1 F O TP- 174 MODE FIELD DIAMETER OF SINGLE-MODE OPTICAL FIBER BY KNIFE-EDGE SCANNI
14、NG IN THE FAR, FIELD This FOTp is a part of the series of test procedures included wi,thin Recoinmended Standard EIA-455. 1. INTENT 1.1 This test method describes a procedure for obtaining the mode field diameter, 2w0, of a Class IVa single-mode fiber. 2. GENERAI, INFORMATION 2.1 Definition The defi
15、nition of Mode Field Diameter contained in this document is appropriate when the fiber near fields and far fields are approximately Gaussian. This is true for Class IVa (dispersion-unshifted) fibers around 1300 nm, but less so around 1550 nm. The calculations of Section 6 are intended only for Class
16、 IVa fibers around 1300 nm. Other wavelengths and fiber classes yielding non-Gaussian fields will be treated at a later date. 2.2 General Procedure The method involves measuring the relative power passed by a knife edge as it is scanned across the output far field of the fiber. The data of power ver
17、sus edge position may be fitted to a complementary error function. This fit gives the angular mode width which is related to the spatial mode field diameter. 3. TEST APPARATUS 3.1 Light Source Use a noncoherent or coherent source, such as tungsten filament lamp, or semiconductor light emitting diode
18、 or laser diode which produces sufficient radiation at the intended measurement wavelengths. A monochromator or interference filter(s) may be used, if required, for wavelength selection. The source shall be stable in intensity over a time period sufficient to perform the measurement. The wavelength
19、of the source shall be specified in the Detail Specification. The nominal spectral linewidth shall be less than or equal to 10 nm full-width at half-maximum (FWHM), Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted wi
20、thout license from IHS-,-,-FOTP- 174 Page 2 3.2 Launch Optics An optical lens system or fiber pigtail may be employed to excite the test fiber. It is recommended that the power coupled into the test fiber be relatively insensitive to the position of the input end face of the test fiber. This can be
21、accomplished by using a launch beam that spatially and angularly overfills the test fiber. If a butt splice is used, means shall be employed (such as index matching material . between the fiber pigtail and test fiber) to avoid interference effects. 3.3 Support and Positioning Apparatus Stably suppor
22、t the input and output ends of the test fiber for the duration of the test; a vacuum chuck may be used. Support the fiber ends such that they can be repeatably positioned in the launch and detection optics. Accurately position the knife edge a fixed distance, D, from the fiber. This may be done, for
23、 example, by using a side-viewing microscope with a crosshair reticle, or a retroreflecting concave mirror with an axis parallel to the knife edge and perpendicular to the fiber. . 3.4 Cladding-Mode Stripper Cladding mode power shall be removed from the test sample, Under some circumstances, the fib
24、er coating will perform this function; otherwise, methods or devices that extract cladding mode power shall be employed at the input and output ends of the test sample. 3.5 High-Order Mode Filter A method shall be employed, if needed, to remove higher order propagating modes at the test wavelengths.
25、 A one-turn bend of radius 30 mm (1.2 in) or less is usually sufficient to do this. 3.6 Knife-Edge Assembly Use a straight thin edge. The fiber-to-edge plane separation must satisfy the far-field condition D 3Ow:/X which is about 0.4 to 0.8 mm (0.016 to 0.031 in). Typical separations range from 5 to
26、 50 mm (0.2 to 2 in). I - Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-_- . EIA 455-174 48- 2575532 0054544 3 = FOTP-174 Page 3 3.7 Scan Apparatus Use a linear translation stage, move
27、d along (for example) by a stepper motor, to scan the knife-edge in a plane perpendicular to the fiber axis and along the X-direction perpendicular to the edge line; 3.8 Detection Optics Couple all the power passing by the knife edge onto the active region of the detector. As an example, an optical
28、lens system can transfer light from the fiber end onto the detector. 3.0 Detector and Signal Detection Electronics Use a detector which is linear over the range of intensities encountered. A typical system might include a photovoltaic-mode Ge or InGaAs photodiode and a current-input preamplifier, wi
29、th synchronous detection by a lock-in amplifier and optical chopper assembly. Generally, a system includes a computer for data analysis. 4. TESTSAMFLE 4.1 The test sample shall be a known length, typically 2 m (79 in), of single- mode fiber. 4.2 Prepare flat endfaces at the input and output ends of
30、the test sample as described in FOTP-57 (EU-455-57), “Optical Fiber End Preparation and Examination“. 5. TESTPROCEDURE . 5.1 Align the prepared test sample to the launch optics, and position it at a known distance to the knife edge. Record the separation D between the fiber end and the plane of the
31、knife-edge. 5.2 Record the far-field power, T(z), transmitted by the knife-edge at a sequence of positions “z“ as defined in 3.7. An example is shown in Figure 1. Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted with
32、out license from IHS-,-,-FOTP-174 Page 4 5.3 To ensure capturing the flat portions of the T(x) transmittance curve, the scan to the left and right of the center x = x, of the curve shall cover a distance exceeding 1.5 w(D) on each side. Here w(D) = xO/.lrw, (= GIA, see section 6) is the far-field mo
33、de radius at the knife-edge plane, typically between 0.4 and 4 mm (0.016 and 0.157 in); D is the separation between the fiber end and the knife-edge plane, and 2w, is the minimum expected value of mode field diameter. To the right side, the scan need not continue beyond the low intensity noise limit
34、. About 10 discrete points are generally sufficient for- the cal c u1 at ion. 6. CALCULATIONS 6.1 Give the knife-edge scan data T(x) a least-squares fit t the expression T,(x) = To erfc A(x - q,) -I where To, A, and x, are the best-fit parameters (see Figure 1 for their meaning), and is the compleme
35、ntary error function, Minimize the deviation O0 (T - Tg)2 da I -03 6.2 Calculate the mode field diameter as & Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. EIA 455-374 88 - 2575532 0
36、054546 7 F OTP- 17 4 Page 5 e 7. DOCUMENTATION 7.1 Test Results The following information shall be reported with each test: 7.1.1 Date of test 7.1.2 Sample identification number 7.1.3 FOTP number 7.1.4 The wavelength(s) used and mode field diameter(s) 2w, obtained, 7.2 Test Documentation For U.S. Mi
37、litary application, brief descriptions of the following items shall be reported for each test. For all other applications, the descriptions need not be reported, but shall be available upon request. The described items are: 7.2.1 Light source 7.2.2 Launch optics 7.2.3 Cladding-mode stripper 7.2.4 Hi
38、gher-order mode filter 7.2.5 Fiber support mechanisms 7.2.6 Knife-edge scanning assembly 7.2.7 Fiber to knife-edge plane separation D 7.2.8 Detection optics 7.2.9 Detection and recording techniques 7.2.10 Computation technique 7.2.11 Name of operator. Copyright Electronic Industries Alliance Provide
39、d by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EIA 455-174 2535532 0054547 9 W 1 II FOTP-174 Page 6 * 8. SUMMARY 8.1 The following shall be specified in the Detail Specification: 8.1.1 FOTP number 8.1.2 Optical wavelength(s) 8.1.3 Fa
40、ilure or acceptance criteria 8.1.4 Number of samples 8.1.5 Other test conditions REFERENCES l l i Mode-field diameter of single-mode fiber by knife-edge scanning in the far- field“, W. Otten, F. Kapron, and T. Olson, Journal of Lightwave Technology, vol LT-4, no. 10, pp 1576-1579 (October 1986) “Con
41、sistency of mode field diameter definitions for fibers with Gaussian and non-Gaussian field profiles in different measurement domains“, W. Anderson and J. Kilmer, Technical Digest - Symposium on Optical Fiber Measurements, NBS Special Pub. 720, pp 49-52 (September, 1986) 2 Copyright Electronic Indus
42、tries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.i- =& EIA 455-174 88 m 2575532 0059548 O m FOTP-174 Page 7 O 2/ X scan distance x Figure 1. Power T(E transmitted as a function of knife-edge position E. The edge blocks the region below 2. Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
