1、_SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising theref
2、rom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2010 SAE International All rights reserved. No part of this publication ma
3、y be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970 (outside US
4、A) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AS5603AAEROSPACESTANDARDAS5603 REV. A Issued 2007-11 Revised 2010-11Superseding AS5603 (R) Digi
5、tal Fiber Optic Link Loss Budget Methodology for Aerospace Platforms RATIONALEThe aerospace industry requires precise standards for avionics system design. To ensure that the aerospace fiber optics industry also adopts these same high standards, it is essential that a common set of fiber optic syste
6、m design procedures be established. This document outlines procedures needed for digital avionics fiber optic link system design that help to assure it complies with aerospace industry best practices. This document may be used as a stand-alone process but is intended to be used in conjunction with A
7、S5750 which specifies key parameters to be provided by the requesting entity. This revision of the document explicitly describes the process and documentation required to perform a digital fiber optic link loss budget. Theoretical derivation, background material, and additional information provided
8、in the original version of this document have been preserved in AIR6113. TABLE OF CONTENTS 1. SCOPE 22. REFERENCES 22.1 Applicable Documents 22.2 Related Publications . 22.3 Definitions . 33. INTRODUCTION. 34. SPECIFICATION AND INFORMATION REQUIREMENTS . 35. PROCEDURE . 35.1 Describe the Digital Opt
9、ical Link . 35.2 Prepare Optical Data 55.3 Perform Calculations . 75.4 Review Results . 116. DOCUMENTATION 117. NOTES 127.1 Revision Indicator 12APPENDIX A RELEVANT STATISTICS (INFORMATIVE) . 13APPENDIX B SAMPLE WORST CASE LOSS BUDGET (INFORMATIVE) . 14Copyright SAE International Provided by IHS und
10、er license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS5603A Page 2 of 151. SCOPE This document defines the steps and documentation required to perform a digital fiber optic link loss budget. This document does not specify how to design a digital
11、fiber optic link. This document does not specify the parameters and data to use in a digital fiber optic link loss budget. 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shallapply. T
12、he applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event ofconflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws a
13、nd regulations unless a specific exemption has been obtained. 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.orgAS5750 Loss Budget Specification for Fiber Opt
14、ic Links 2.2 Related Publications The following publications are provided for information purposes only and are not a required part of this SAE Aerospace Technical Report. 2.2.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (i
15、nside USA and Canada) or 724-776-4970 (outside USA), www.sae.orgAIR6113 Guidelines for Design of Digital Fiber Optic Link Loss Budget Methodology 2.2.2 RTCA Publications Available from Radio Technical Commission for Aeronautics Inc., 1828 L Street, NW, Suite 805, Washington, DC 20036, Tel: 202-833-9
16、339, www.rtca.orgDO-160 Environmental Conditions and Test Procedures for Airborne Equipment 2.2.3 TIA Publications Available from Telecommunications Industry Association, 2500 Wilson Boulevard, Suite 300, Arlington, VA 22201, Tel: 703-907-7700, www.tiaonline.org/standards/TIA-440-B Fiber Optic Termi
17、nology TIA-455 Fiber Optic Test Procedures 2.2.4 U.S. Government Publications Available from the Document Automation and Production Service (DAPS), Building 4/D, 700 Robbins Avenue, Philadelphia, PA 19111-5094, Tel: 215-697-6257, http:/assist.daps.dla.mil/quicksearch/MIL-STD-810 Environmental Engine
18、ering Considerations and Laboratory Tests MIL-STD-2052 Fiber Optic Systems Design Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS5603A Page 3 of 152.3 Definitions ACTUAL MARGIN: This parameter
19、 is represented by MACT. This parameter is the calculated amount of additional optical power in the digital optical link. ACTUAL SATURATION MARGIN: This parameter is represented by MACT(SAT). This parameter is the calculated amount of excessive optical power in the digital optical link. This paramet
20、er is typically optional in calculating digital fiber optic linkloss budgets. CONFIDENCE LEVEL: This parameter is represented by C. This parameter is the numerical value representing the quality of the data provided and the results of the digital fiber optic link loss budget. REQUIRED MARGIN: This p
21、arameter is represented by MREQ. This parameter is an amount of optical power in the digital optical link set aside to accommodate unknown and unexpected losses. REQUIRED SATURATION MARGIN: This parameter is represented by MREQ(SAT). This parameter is an amount of optical power in the digital optica
22、l link set aside to accommodate losses that have not occurred and unexpected gains. This parameter is typically optional in calculating digital fiber optic link loss budgets. 3. INTRODUCTION This document details three methods for calculating a digital optical loss budget. These include the Worst Ca
23、se Method, the Statistical Method, and the Numerical (Simulation) Method. These methods require increasing effort but provide increasing accuracy. Note that AS5750 allows for using a more accurate method over the method selected. The method to perform a digital optical loss budget is broken down int
24、o three general stages: specification, procedure, and documentation. In the specification stage, the high level goal of the digital optical loss budget is captured. In the procedure stage, the steps to accomplish the digital optical loss budget are provided. In the documentation stage, the informati
25、on generated by the digital optical loss budget is described. 4. SPECIFICATION AND INFORMATION REQUIREMENTS The following details shall be specified when using this standard: a. Base loss budget calculation method to be used (I Worst Case, II Statistical, or III Numerical (Simulation). If no method
26、has been selected, I Worst Case is selected by default. b. The specific defined parameter value for required margin, MREQ.c. The specific defined parameter value for confidence level, C.If required, the following details shall be specified before using this standard: d. The specific defined paramete
27、r value for required saturation margin, MREQ(SAT).Note that AS5750 provides the information necessary for this step. 5. PROCEDURE 5.1 Describe the Digital Optical Link The first step is to generate a complete description of the digital optical link. This description starts with the optical sourceof
28、the digital optical link where the digital information is first converted to light, for example, a directly modulated laser. The description ends with the optical destination where the light is converted back to digital information, for example, a photodiode. For complex optical systems where the li
29、ght from one optical source may reach more than a single optical destination, each significantly different optical path between a single optical source and multiple optical destinations should be treated as different digital optical links and should have separate digital optical loss budgets calcula
30、ted for each resulting digital optical link. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS5603A Page 4 of 155.1.1 Description List A description list of the digital optical link shall be gen
31、erated. 5.1.1.1 Describe Optical Source The optical source of the digital optical link shall be included in the description list of the digital optical link. The opticalsource shall be identified uniquely. An example of unique identification is “Unit A, laser 3.” The type of optical source and manuf
32、acturer should be noted. 5.1.1.2 Describe Optical Elements The optical elements of the digital optical link shall be included in the description list of the digital optical link. Typicallythese optical elements are part of an optical cable plant. Optical elements are components or interfaces that ma
33、y significantly affect the propagation of light along with the optical source and optical destination. Table 1 is a list of itemsthat shall be included if present in the digital optical link. For example, include a connector if the digital optical link has a connector between the optical source and
34、the optical destination but do not include a wavelength demultiplexer if the digital optical link does not have a wavelength demultiplexer. Note that some of these elements may have negligible effects on the digital optical link. If there are duplicate optical elements in the digital optical link, e
35、ach duplicate opticalelement shall be listed separately in the description list. Note that some optical systems have optical elements not listed in Table 1. These optical elements unlisted in Table 1 shall be included in the description list. Each optical element included in the description list sha
36、ll be identified uniquely. An example of unique identification is “Unit B, filter 2, port 1 to port 3.”The type of optical element and manufacturer should be noted. 5.1.1.3 Describe Optical Destination The optical destination of the digital optical link shall be included in the description list of t
37、he digital optical link. The opticaldestination shall be identified uniquely. An example of unique identification is “Unit B, PIN diode 4.” The type of optical destination and manufacturer should be noted. TABLE 1 OPTICAL ELEMENTS TO INCLUDE IN DESCRIPTION LIST Optical Element Comment Connector Ther
38、e may be a variety of connector types in an optical link. This optical loss value is based on the insertion loss of a mated pair of optical termini. Attenuator Mode Conditioning Cable Wavelength Filter Include multiplexing and demultiplexing elements Optical Isolator Typically used with lasers and o
39、ptical amplifiers to suppress the reverse flow of light Optical Switch This device routes light from a select input to a select output and does not convert to an electrical signal Coupler Also referred to as combiner, star coupler, power splitter, and monitor tap Modulator Optical Amplifier Optical
40、Fiber Loss measured over planned length of the optical fiber Optical Waveguide Loss measured over planned length of the optical waveguide Splices Mechanical splices are more likely to have significant losses to merit inclusion in the optical element list while fusion splices are typically negligible
41、Mode Field Adapters These devices are typically used in single-mode fiber optic systems to adjust between sections of differing mode fields Extreme Optical Fiber Bends Bends that are permanently planned in the design and not transitory Copyright SAE International Provided by IHS under license with S
42、AENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS5603A Page 5 of 155.1.2 Environmental Conditions The expected environmental conditions for the digital optical link shall be documented. The environmental conditions for different parts of the link should be d
43、ocumented separately if the environmental conditions for different parts of the link aresignificantly different. Environmental conditions shall include temperature range and vibration spectrum. There are many other environmental conditions that should be included. See AIR6113, MIL-STD-810, or RTCA D
44、O-160 for a more complete list and descriptions of potential environmental conditions. As a guideline, environmental conditions would be documented if they significantly impact any item in the description list. Note that a seemingly insignificant impact in a single item in the description list may b
45、ecome significant when grouped with other items that are impacted in the same fashion. 5.1.3 Additional Characteristics If there are any additional characteristics to be separately accounted for in the digital optical link, they shall be documented. These characteristics may be additional penalties
46、or adjustments that capture the interaction between the components in the optical link. The effects of these additional characteristics are typically accounted for in the optical lossdata and do not need to be extracted and included separately. See AIR6113 for a list and descriptions of potential ad
47、ditional characteristics. 5.1.4 Review Description Once the description list, environmental conditions, and additional characteristics are documented, they shall be provided to the entity requesting the loss budget. Ideally, this information should be reviewed with the entity before continuing. This
48、 step ensures completeness and agreement on the description list and the included environmental conditions before investing further effort. 5.2 Prepare Optical Data Optical data is needed for every item in the description list. This information may come from a variety of sources. These sources are listed in Table 2. TABLE 2 SOURCES FOR OPTICAL DATA Optical Data Source Comment Field data This is data collected from fielded components Test data This is data taken with a test setup in a laboratory Manufacturer specification CalculatedThe optical data
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