Review: Corning's Thunderbolt Optical Cable

Posted:
in General Discussion edited October 2014
Already in its second generation, the Thunderbolt I/O protocol has been around for three years, but only recently did manufacturers begin production of optical cables to deliver the tentpole feature of long-distance data transfer. AppleInsider was able to test out this highly anticipated addition with Corning's 10m all-optical Thunderbolt cable solution.

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After months of development, glass manufacturing giant Corning -- which produces the Gorilla Glass used by Apple in its iOS product line -- was first to bring an optical Thunderbolt cable to market late last year. With Optical Cables by Corning, the promise of long-distance high-speed interconnects, touted since the first-generation Thunderbolt-equipped computers hit store shelves in 2011, has finally been fulfilled.

Design

The ten-meter Corning Thunderbolt Optical Cable is extremely light; its weight is perhaps one of the first things we noticed when taking it out of the box. Compared to a conventional copper or metal-core Thunderbolt cable, such as Apple's branded two meter variant, the difference is immediately evident.

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Corning's thunderbolt Optical Cable (left) coiled in concentric circles next to Apple's identically wound 2m Thunderbolt cable.


Traditional cables pack in individual wires, shielding, insulation and braids into a usually thick jacket. Using a laser engine solution, the Corning cable does not require the same support structures and is essentially one strand of glass-based fiber with an 80-micrometer core covered by rubberized sheathing.

The one component that is larger than the corresponding part found on a regular copper Thunderbolt cable is the Optical's plug. While not substantially thicker, the plug is made longer to accommodate a transceiver, converter and incorporated laser.

In transferring data, the first plug converts an incoming signal from electrical to light energy, which is subsequently transmitted through the fiber to a second plug. Light is then reconverted into an electric signal and fed into the accessory or host computer's Thunderbolt controller.

Corning fits all conversion processing logic and associated hardware into the small rectangular plug, which sips power from Thunderbolt's drive line to function. As a Class 1 Laser product, the Optical is basically a small powered extension of a computer's Thunderbolt I/O hardware; a necessity to transfer data at speed over long distances.

With Thunderbolt's optical requirements, the light engine is offloaded to the cable, thus allowing for backwards compatibility with earlier versions of the protocol and less hardware for the host machine.

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Corning's Thunderbolt Optical Cable (left) compared to Apple's Thunderbolt cable.


Corning is using its proprietary ClearCurve VSDN optical fiber in the Thunderbolt Optical. A slender yet robust material, ClearCurve can handle a surprisingly high level of abuse. The fiber can be twisted, bent, tied into knots and squeezed without detrimentally affecting data transfer. This is a good trait to have, especially since the ultra-thin and long cable becomes easily tangled.

Despite being eight meters longer than the Apple cable, the Corning wraps into a neat and manageable bundle thanks to its ultra-thin core. Unlike other advanced cable technologies, the Optical can be coiled without a special winding regimen, though we would advise the "over under" method to preserve joint integrity.

Overall build quality is very high; the plugs, cable and joints all feel solid. It should be noted that, while rugged, any damage to or break in the cable will likely require replacement. Unlike copper, fiber is not easily patched and threshold tolerances in optics alignment are extremely tight.

In Use

In our tests, we connected Apple's latest Mac Pro to Promise's Thunderbolt 2-equipped Pegasus2 RAID array (which we reviewed earlier in February), a late-2013 MacBook Pro with Retina display and other various Thunderbolt storage accessories.

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First we ran a few performance tests with the RAID array, swapping out the Corning with the two-meter Apple cable and a one-meter generic. There was no distinguishable difference in speed between the three products. Peak read speeds hit 454 MB/s, while write speeds topped out at 540 MB/s. We did note fluctuations in read/write times, but since it occurred with each cable, we attributed it to the RAID 5 setup and OS X's handling of the corresponding logical drive.

To get a more reliable reading, we switched to file transfers between the Mac Pro and Retina MacBook Pro. Here, speeds were much more stable thanks to each machine's internal SSD and zippy PCIe interface. We were able to transfer 3GB movie files in less than five seconds and batch moves were equally as fast. As our test machines don't have terabytes of storage, we could only test files and folders up to approximately 100GB in size.

During testing, the plugs reached temperatures much higher than any other consumer interconnect we have used. Corning assured us that the composite caps may become warm to the touch, but assured us that the thermals are within Intel's specifications.

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Since performance is identical to non-optical competitors, the next logical comparison is implementation. This is the Corning's main draw and it delivers. Copper Thunderbolt cables are limited to three meters in length, while the Optical starts at ten meters and can go up to 100 meters.

Previously, professionals had to keep Thunderbolt storage and accessories within arm's reach of their computer, but the Corning Optical lets them put those devices away from their workspace, even in another room. The cable's thin profile also allows users to inconspicuously snake the cable along a wall's baseboard, effectively hiding it from view and protecting it from accidental removal.

Finally, the Optical's single-body structure makes it highly flexible. Whereas copper Thunderbolt interconnects are thick and difficult to maneuver, Corning's version is easy to work with even in the tightest of spaces.

Conclusion

Corning's Thunderbolt Optical Cable is a well-designed and durable interconnect. Compared against thick copper cables, the deceivingly thin and light cable can take as much or more abuse from everyday wear and tear.

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This is not to mention that it's one of the only fiber Thunderbolt cables on the market. Aside from Corning, not many manufacturers are ready to enter the nascent market. One alternative that comes to mind is Other World Computing's recently-released 10-, 20- and 30-meter cables, though we have yet to test a sample and cannot comment on the lineup's performance.

For users who want the fastest connections speeds at distance, there is little choice but to pay the premium for Corning's offering. All things considered, however, the price is representative of the cable's design, materials and manufacturing, making it an easy recommendation.

One thing to consider before buying is that the Optical can only be used with self-powered accessories. The cable is not compatible with devices that require power from a host device, examples being certain bus-powered portable hard drives.

Score: 4.5 out of 5

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Pros:

  • Super thin and light
  • Maintains Thunderbolt speeds well over ten feet
  • Well constructed

Cons:

  • Pricey compared to other I/O tech.
  • Must replace upon breakage.

Where to Buy

We found B&H Photo currently offers the lowest prices for Corning's Optical Cable, with the 10m coming in at $299, the 30m for $659 and 60m for $1,299.
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Comments

  • Reply 1 of 35
    cnocbuicnocbui Posts: 3,613member
    Thunderbolt doesn't seem to have much of a future outside of commercial applications. The one use for it I would have is to allow external Graphics cards to by used with my MBPR, but although the idea has been mooted, there are still no real implementations that I am aware of.

    Those optical cables make SCSI ones look cheap. Great technology, pity about the price.
  • Reply 2 of 35
    macxpressmacxpress Posts: 4,578member

    With things going wireless and USB being sufficient for most users needs, I really can't see many people beyond professionals needing extremely fast wired I/O. This fills whats necessary for the people who really need it. Us as regular consumers don't necessarily need extremely fast wired I/O, its nice to have don't get me wrong but its not entirely necessary either. Perhaps this is the reason why its not taking off in the mainstream market. I would put it in the category with FireWire. It was used and it was fast for its time, but it wasn't really ever mainstream when compared to something like USB. I'm not saying that USB is better...I really don't like USB and wished FireWire would have taken off more than it did, but the fact is that it didn't. I see Thunderbolt doing the same thing for the same reason FireWire never really took off. 

  • Reply 3 of 35
    This is fantastic technology. Hope we'll see a something that can go from a Thunderbolt port to already installed fibre optic cabling.
  • Reply 4 of 35
    There seems to be a lot of weight/sag on the connection to the MP?
  • Reply 5 of 35
    I'm surprised Apple can't provide in this day and age at least one of those Thunderbolt ports with an optical interface inside the MP already...
  • Reply 6 of 35
    normmnormm Posts: 521member
    You write,

    "One alternative that comes to mind is Other World Computing's recently-released 10-, 20- and 30-meter cables, though we have yet to test a sample and cannot comment on the lineup's performance."

    OWC seems to have similar prices for their optical thunderbolt cables. Wouldn't this have been a good place to test both and compare? Though since they probably use the same chips they're unlikely to be much different.
  • Reply 7 of 35
    The biggest use I see for these optical cables is extreme speed networking. With this, you have a 20Gb/sec network up to 100m between Macs. Even gigabit Ethernet has a theoretical 125MB/sec and 40MB/sec real world speed. 540MB/s is faster than even the old Mac Pro could write to its internal drives!
  • Reply 8 of 35
    Quote:

    Originally Posted by Lance Newcomb View Post



    The biggest use I see for these optical cables is extreme speed networking. With this, you have a 20Gb/sec network up to 100m between Macs. Even gigabit Ethernet has a theoretical 125MB/sec and 40MB/sec real world speed. 540MB/s is faster than even the old Mac Pro could write to its internal drives!

     

    Looking at the specs Corning is very reticent to give real world numbers for this. They claim 10gbit/s bidirectional but a real 10gbit SFP and fibre patch is probably going to come to a higher price and takes up more space. I can only assume that they have had to make some sacrifices in order to get to this level, potentially confirmed by the test above only hitting ~4.5gbit/s.

     

    Shame I don't have anything new enough to have thunderbolt on it. Would like to hook up a real world 10gbit tester and see just how it deals with realistic 'layer 7' traffic.

  • Reply 9 of 35
    "Must replace upon breakage"?? Seriously? Did your editor/grade school teacher say you must always have two bullet points after a topic?
  • Reply 10 of 35
    Have yet to find the need for Thunderbolt for much of anything yet, my guess is that need comes to light quickly when 2160P (4K) and 4320P (8K) video becomes more mainstream...
  • Reply 11 of 35
    MarvinMarvin Posts: 14,179moderator
    "Must replace upon breakage"?? Seriously? Did your editor/grade school teacher say you must always have two bullet points after a topic?

    Some electrical cables can be repaired like a co-ax cable for example. If the optical cable is cut in the middle, it probably can't be repaired so replacing the entire expensive cable is the only option.
  • Reply 12 of 35
    Quote:

    Originally Posted by Marvin View Post





    Some electrical cables can be repaired like a co-ax cable for example. If the optical cable is cut in the middle, it probably can't be repaired so replacing the entire expensive cable is the only option.

     

    You are almost 100% certainly right. Splicing fibre is the most annoying thing in the world plus you're going to need an OTDR that's 6 figures, a selection of extremely fine 3m polishing gear and a 6 figure fuser.

     

    A common misconception is that 'TOSLINK' is the same as optical fibre. They are really nothing alike as I'm sure you know.

  • Reply 13 of 35
    OK my bad!
  • Reply 14 of 35
    What if you need to put your PCI Expansion chassis 11 meters from your Mac Pro? You're SOL.
  • Reply 15 of 35
    sockrolidsockrolid Posts: 2,788member
    "Must replace upon breakage."

    Same as anything else. Right?
  • Reply 16 of 35
    ahmlcoahmlco Posts: 432member
    Quote:

    Originally Posted by Suddenly Newton View Post



    What if you need to put your PCI Expansion chassis 11 meters from your Mac Pro? You're SOL.

     

    You did see the part about lengths up to 100m, right?

  • Reply 17 of 35
    Quote:
    Originally Posted by ahmlco View Post

     

     

    You did see the part about lengths up to 100m, right?


     

    What if you need to put your PCI Expansion chassis 101 meters from your Mac Pro? You're SOL.

     

    P.S. I am parodying how the haters argue on these forums :)

  • Reply 18 of 35
    asciiascii Posts: 5,848member

    Coolest computer connection cable ever.

  • Reply 19 of 35
    sflocalsflocal Posts: 4,244member
    Quote:

    Originally Posted by libertyforall View Post



    Have yet to find the need for Thunderbolt for much of anything yet, my guess is that need comes to light quickly when 2160P (4K) and 4320P (8K) video becomes more mainstream...



    For the regular consumer, Thunderbolt doesn't provide much, but it's there.  I'm a convert.  I love that I can hook up my Thunderbolt display to my MBA with all the USB, Ethernet, etc  going on one cable. 



    I've used TB to TB between machines (in Target Mode) to transfer large virtual machines to their final destination.  When I can transfer gigabytes of data in seconds, that is a huge deal.



    I think for the foreseeable future, TB will be used mainly by those in the professional industry and the tech-saavy.



    I'm waiting for TB2 to come out for the iMac and then it will be time to replace my trusty 2009 iMac.  

  • Reply 20 of 35
    solipsismxsolipsismx Posts: 19,566member
    macxpress wrote: »
    With things going wireless and USB being sufficient for most users needs, I really can't see many people beyond professionals needing extremely fast wired I/O. This fills whats necessary for the people who really need it. Us as regular consumers don't necessarily need extremely fast wired I/O, its nice to have don't get me wrong but its not entirely necessary either. Perhaps this is the reason why its not taking off in the mainstream market. I would put it in the category with FireWire. It was used and it was fast for its time, but it wasn't really ever mainstream when compared to something like USB. I'm not saying that USB is better...I really don't like USB and wished FireWire would have taken off more than it did, but the fact is that it didn't. I see Thunderbolt doing the same thing for the same reason FireWire never really took off. 

    Why does video never get mentioned or do you think the future of video will be wireless or USB? I don't see that happening, especially with UHD coming down the line.

    Since TB brilliantly uses the same port interface as mDP I see no reason to assume that TB is failure unless we are to assume that the commonly unused but included external display ports are a failure.

    "Must replace upon breakage"?? Seriously? Did your editor/grade school teacher say you must always have two bullet points after a topic?
    sockrolid wrote: »
    "Must replace upon breakage."

    Same as anything else. Right?

    Perhaps they should have written. "More susceptible to breakage when cable in bent too much."
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