Intensity modulation

<h2 id="intensity-modulation-with-direct-detection">Intensity modulation with direct detection</h2>
<p>Intensity Modulation / Direct Detection (IM/DD) is a scheme is simple and cost-effective in fiber optic communication, making it a suitable for various optical communication applications. It involves modulating the optical power of the carrier signal to represent the transmitted data. This modulation can be achieved using techniques, such as <a href="/facts/On%E2%80%93off_keying/8HkJV9am">on-off keying</a> (OOK). The intensity-modulated optical signal is generated by modulating the amplitude or the current of the light source, typically a laser diode with one or two cavity designs such as <a href="/facts/Fabry-Perot/n949LwQD">Fabry-Perot</a> or <a href="/facts/Distributed-feedback_laser/6PJvoQ5P">distributed feedback</a> (DFB).<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a>
</p><p>At the receiver end, direct detection (DD) is used to recover the modulated signal. The modulated optical signal is detected by a <a href="/facts/Photodetector/7cSkXS6s">photodetector</a> (most commonly <a href="/facts/PIN_photodiode/H4hdX9Un">PIN</a> or APD <a href="/facts/Photodiode/152Rpk06">photodiode</a>), which converts the optical power variations into corresponding electrical current or voltage variations. The output of the photodetector is then processed and decoded to retrieve the original information.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a>
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<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Photoacoustic_Doppler_effect/VjSqyfuw">Photoacoustic Doppler effect</a></li></ul>

<p> This article incorporates <a href="/facts/Copyright_status_of_works_by_the_federal_government_of_the_United_States/Q1jvr96g">public domain material</a> from <a href="https://web.archive.org/web/20220122224547/https://www.its.bldrdoc.gov/fs-1037/fs-1037c.htm"><i>Federal Standard 1037C</i></a>. <a href="/facts/General_Services_Administration/Np3opv9x">General Services Administration</a>. Archived from <a href="https://www.its.bldrdoc.gov/fs-1037/fs-1037c.htm">the original</a> on 2022-01-22. (in support of <a href="/facts/MIL-STD-188/D5rsvdsW">MIL-STD-188</a>).
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<h2 id="further-reading">Further reading</h2>
<ul><li>William Shieh, Ivan Djordjevic, <i>OFDM for Optical Communications</i>, Academic Press, 2009 <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-12-374879-8.</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>T. Okoshi, Coherent Optical Fiber Communications, pages 2-3, Springer, 1988 ISBN 9027726779. <a href="/wiki/ISBN_(identifier)" target="_blank">/wiki/ISBN_(identifier)</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>T. G. Hodgkinson, D. W. Smith, R. Wyatt, D. J. Malyon, "Coherent optical fibre transmission systems", in Bishnu P Pal (ed), Fundamentals Of Fibre Optics In Telecommunication And Sensor Systems ,page 470, Bohem Press, 1992 ISBN 8122404693. <a href="/wiki/ISBN_(identifier)" target="_blank">/wiki/ISBN_(identifier)</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Chinlon Lin, "Opto-electronics and the information age: a perspective", in Bishnu P Pal (ed), Fundamentals Of Fibre Optics In Telecommunication And Sensor Systems ,page 20, Bohem Press, 1992 ISBN 8122404693. <a href="/wiki/ISBN_(identifier)" target="_blank">/wiki/ISBN_(identifier)</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Ananth Selvarajan, Subrat Kar, T. Srinivas. Optical Fiber Communication: Principles and Systems, page 129, Tata McGraw-Hill Education, 2003 ISBN 0070445567. <a href="/wiki/ISBN_(identifier)" target="_blank">/wiki/ISBN_(identifier)</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>Cox, C.; Ackerman, E.; Helkey, R.; Betts, G.E. (August 1997). "Techniques and Performance of Intensity-Modulation Direct-Detection Analog Optical Links". IEEE Transactions on Microwave Theory and Techniques. 45 (8): 1375–1383. doi:10.1109/22.618439. ISSN 0018-9480. <a href="https://ieeexplore.ieee.org/document/618439" target="_blank">https://ieeexplore.ieee.org/document/618439</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>Cox, C.; Ackerman, E.; Helkey, R.; Betts, G.E. (August 1997). "Techniques and Performance of Intensity-Modulation Direct-Detection Analog Optical Links". IEEE Transactions on Microwave Theory and Techniques. 45 (8): 1375–1383. doi:10.1109/22.618439. ISSN 0018-9480. <a href="https://ieeexplore.ieee.org/document/618439" target="_blank">https://ieeexplore.ieee.org/document/618439</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
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Intensity modulation open-in-new

Intensity modulation