Talk:Multi-mode optical fiber

Untitled
The 400MB/s FC-AL standard offers 2Gbps over 70m of multimode fiber (62.5µm) according to Fibre Channel. Additionally, there are two popular types of multimode fiber: 62.5µm and 50µm. These measures indicate the size of the fiber's core. These two core sizes have slightly different attenuation properties and generally should not be mixed (which causes greater attenuation). Both sizes of multimode fiber are recognized in the standards for Ethernet (IEEE 802.3), Fibre Channel, ATM, FDDI, and Token Ring (among others). —Preceding unsigned comment added by 208.20.220.72 (talk • contribs) 10:40, February 1, 2006


 * The Fiber Optics LAN Section has updated the section on multimode fiber to help ensure that it reflects the current capabilities of the medium. We are concerned that based on the previous information provided, readers would believe that multimode fiber had transmission capabilities of only 1 Gb/s, when in fact, there are grades of multimode fiber now that easily support 10 Gb/s and beyond. The page made no reference to the development of fiber types such as Laser optimized multimode fiber, which enables multimode fiber to be used with Vertical Cavity Surface Emitting Lasers (VCSELs) among other omissions. —Preceding unsigned comment added by Lizgo (talk • contribs) 12:43, July 13, 2007

Market analysis
The references about the market analysis thing need removing and putting in a footnote :) Arghlookamonkey 20:22, 28 October 2007 (UTC)


 * I have removed the following text, as not properly cited. If a published source (online or print) can be provided, the material can be reinstated. A link to the website of the market researcher is not sufficient, unless the claims in this paragraph can be found there. If so, a link directly to the page containing the relevant material would be required.
 * "According to research conducted by Matthew O. Burroughs (www.marketsharetrends.com) the predominant multi-mode fiber deployed today is still legacy 62.5/125 µm multi-mode fiber, although 50/125 µm fiber, including all bandwidths, is expected to surpass 62.5/125 µm by the end of 2007. Of the 50/125 µm fiber being deployed today, slightly more than half is..."


 * Also note that the reference to "today" is inappropriate for an encyclopedia, and the "expected to surpass" claim violates the crystal ball policy.--Srleffler 20:43, 28 October 2007 (UTC)

Can Multiple Signals be carried simultaneously through the same fiber
As the multi-mode fiber can accomated multiple modes. does this mean that multiple signals can be passed at the same time. if so how many channels? this point is missing in the articleAp aravind (talk) 10:45, 13 February 2010 (UTC)


 * Yes, but not the way you think. Both single and multimode fiber can carry multiple signals at the same time, with individual signals either separated by wavelength (wavelength division multiplexing) or by interleaving the signals in time (time division multiplexing). The multiple transverse modes in multimode fiber are not independently useful: it is difficult to deliberately launch light into one mode, and as the light propagates down the fiber it may "leak" from one transverse mode to another.--Srleffler (talk) 05:58, 14 February 2010 (UTC)

622Mbps Upper limit of LED modulation?
I'm not convinced there exists an LED modulation limit at a specific data rate. I have looked through the internet and the references given, and the earliest mention I can find of this number is this paper:

Knobloch, A.; Kiesel, P.; Dohler, G.H.; Windisch, R.; Dutta, B.; Borghs, G.; Heremans, P.;, "Modulation Behaviour of Highly Efficient Non-Resonant Cavity Light-Emitting Diodes," Solid-State Device Research Conference, 1999. Proceeding of the 29th European, vol.1, no., pp. 520- 523, 13-15 September 1999 doi: 10.1109/ESSDERC.1999.195136

They do not say it is a maximum limit, they just say they have achieved it.

I want to change the sentence "LEDs have a maximum modulation rate of 622 Mbit/s because they can not be turned on/off fast enough to support higher bandwidth applications." (which is lifted straight from the 1st reference) to something like "LEDs have a maximum modulation rate because they cannot be modulated fast enough to support higher bandwidth applications - they begin to act capacitatively".

Can anyone find a (peer-reviewed) reference that supports 622MBits/sec - there's a fair few "white papers" etc on the internet which mention it, but not why. Toomuchrockcankill (talk) 17:05, 13 January 2011 (UTC)

Professional quality
Thank you to whomever followed up on my edit last night regarding jacket colors. I was having trouble following it myself, and modified the article the best I could, but the current version is even better!

New distances
made some technical changes. The edit comment cited IEEE 802.3-2012 which appears to be a new ref. I believe the previous numbers were correct for previous versions of the standard. I have reverted the changes until someone can add the citation and verify. ---—Kvng 14:08, 10 November 2012 (UTC)

We use MultiMode OM1 with 1Gbps speed on 2000M using Mode Conditioning. Should this be mentioned in this article? I don't have references on hand 198.161.238.19 (talk) 23:37, 14 March 2013 (UTC)

But what is it?
How about a section that describes exactly what multimode fibre actually is? As it stands, the article only describes what it isn't; in other words, how it differs from single mode fibre. Reading the article on single mode fibre isn't exactly enlightening, either. 81.136.202.93 (talk) 15:10, 18 September 2013 (UTC) The Wikipedia community encourages you to be bold in updating pages. Don't worry too much about making honest mistakes—they're likely to be found and corrected quickly. If you're not sure how editing works, check out how to edit a page, or use the sandbox to try out your editing skills. New contributors are always welcome. You don't even need to log in (although there are many reasons you might want to). --Srleffler (talk) 03:43, 27 May 2018 (UTC)
 * You missed the link to optical fiber in the first sentence.--Srleffler (talk) 05:51, 20 September 2013 (UTC)
 * Yes, but there is no description into what "multimode" is. What is a "mode". I know the answer, as I'm in the industry, but the point is: there is no description in the article, nor a link to a good description. — Preceding unsigned comment added by 131.155.215.79 (talk) 11:06, 21 December 2016 (UTC)
 * Very true - I've tried to add a sentence to the lead and explain the point as short as possible. --Zac67 (talk) 18:01, 21 December 2016 (UTC)
 * Not only a section on what it is, but a statement about the applications. The article assumes the only use for a multimode fiber is telecomm.  After stating what it is and how it functions there should be something about its use in communications and in sensing, lighting, or other applications.  The article should then be separated into a comm section and an other applications section; or the title of this article could just be changed to reference multimode fiber in communications.  John N. (talk) 00:13, 27 May 2018 (UTC)
 * Information.svg Thank you for your suggestion. When you believe an article needs improvement, please feel free to make those changes. Wikipedia is a wiki, so anyone can edit almost any article by simply following the edit this page link at the top.

To hyphenate or not to hyphenate
There is some inconsistent usage re: spelling - multimode vs. multi-mode. I have a sense that the former is probably the correct form, but I can't find what I would call the authoritative reference. If anyone knows, please point it out. — Preceding unsigned comment added by 12.177.68.254 (talk) 01:03, 27 May 2015 (UTC)

The TIA-568.3-D standard uses "multimode" and "single-mode." This is a standard that must be purchased to view, hovever. RockyGNgoat (talk) 20:59, 4 July 2022 (UTC)

Should OM5 be added?
OM5 is currently in the tentative stage, but most specs are set in place (see TIA TIA-492AAAE). Should it be added to the table or wait until officially out? Bdh008 (talk) 15:39, 23 March 2017 (UTC)

The computer industry brings out new specs to keep pricing elevated. OM5 fiber is in the talking stage and does not exist yet nor is it needed. OM3 and OM4 multimode fiber have been out for some time. There is little or no difference in the fiber, both are capable of 10GB and going the speed of light which we have not been able to achieve. So there is really no need for OM5. While OM3 cables (50U) have a place OM4 with barely a difference have not sold well. Typically OM3 & OM4 are aqua in color. OM1 is orange. For most applications OM1 is more than adequate. Just be aware OM1 can be 62.5/125 or 50U. While equipment requiring 62.5 can usually accept 50U the reverse is not true. The best thing is to buy from a place that can help you choose the right fiber.

Getting the right fiber is the 1st step. A lot has been written about obtaining gigabyte with copper cables cables and while it may on the surface seem like a less expensive alternative, the speed is obtained by the hardware not the cable. With fiber the equipment has not caught up to the cable which means that the fiber cable is far ahead of any speeds available through hardware. So if you choose the fiber route you are easily 25yrs ahead of any advancements in the hardware. This makes the fiber choice a less expensive alternative and a good insurance policy against any potential advancements and having to replace cable.


 * OM5 is currently only a marketing term and unless it's widely accepted (unlikely) it can only be included under "Various marketing terms" or so. However, OM1 is far inferior to more advanced types – 10GBASE-SR shows this very clearly, higher speeds make OM1 useless. Differences for OM3 and OM4 can be found in the article. Light does not nearly travel a fiber at the speed of light in vaccum, it's usually at around 67% c0. Note that I've removed the marketing link from your comment. WP is no link list or advertising platform. WP is also no how-to site. --Zac67 (talk) 19:11, 7 March 2018 (UTC)
 * PS: Apparently, OM5 has been standardized by TIA and ISO last year. As with all pay-walled standards, hard facts are scarce – I've added what I could find. --Zac67 (talk) 12:58, 28 March 2018 (UTC)

LRM
OM1 can do 10 Gbps w/LRM optics? — Preceding unsigned comment added by 66.192.207.194 (talk) 15:06, 28 June 2017 (UTC)


 * Yes, check out 10GBASE-LRM and IEEE 802.3 Clause 68.5. 10GBASE-LX4 could even do 300 m. --Zac67 (talk) 16:44, 28 June 2017 (UTC)

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