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Review: Corning's Thunderbolt Optical Cable

post #1 of 35
Thread Starter 
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.

Optical


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.

Optical
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.

Optical
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.

Optical


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.

Optical


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.

Optical


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



ratings_hl_45.png

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.
post #2 of 35
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.
post #3 of 35

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. 

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post #4 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.
post #5 of 35
There seems to be a lot of weight/sag on the connection to the MP?
post #6 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...
post #7 of 35
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.
post #8 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!
post #9 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.

post #10 of 35
"Must replace upon breakage"?? Seriously? Did your editor/grade school teacher say you must always have two bullet points after a topic?
post #11 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...
post #12 of 35
Quote:
Originally Posted by kustardking View Post

"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.
post #13 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.

post #14 of 35
OK my bad!
post #15 of 35
What if you need to put your PCI Expansion chassis 11 meters from your Mac Pro? You're SOL.

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post #16 of 35
"Must replace upon breakage."

Same as anything else. Right?

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post #17 of 35
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?

post #18 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 :)

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post #19 of 35

Coolest computer connection cable ever.

post #20 of 35
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.  

post #21 of 35
Quote:
Originally Posted by macxpress View Post

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.

Quote:
Originally Posted by kustardking View Post

"Must replace upon breakage"?? Seriously? Did your editor/grade school teacher say you must always have two bullet points after a topic?
Quote:
Originally Posted by SockRolid View Post

"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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post #22 of 35

I realize the Thunderbolt port is copper-based, being converted to a fiber optic cable in the cable transceiver but I'm wondering if anyone will build an old-style copper-to-fiber transceiver adapter box. I used to use them at work, going from a copper ethernet cable to a fiber cable. You can get a 100m 10Gbps LC-LC fiber cable for under $200 so Corning's transceivers cost ~$500 each. I know copper-to-fiber adapter boxes cost a whole lot less than that. Of course, having everything in a simple package is worth a lot but $1300 is still a lot of money, even for professional installations.

 

Has anyone tested the DisplayPort/TB port with cable to see how well it stays in place? If I was going to pay $1300 for a cable, I'd want to make sure it doesn't slip out. I'd hate to use some funky cable holder on a Mac Pro just to make sure it doesn't fall out.

post #23 of 35
Quote:
Originally Posted by sflocal View Post
 

...
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.
...

Have you ever tried using Pooch, http://daugerresearch.com/pooch/top.shtml, to build a Mac cluster using TB as the connection method? It would be interesting to see if this would work and since you have at least two Macs with TB, all you'd need is the software. Pooch works over ethernet and that protocol is available through TB so it might work. Maybe you could talk to Dean Dauger and see if he'd be willing to work with you to get it to work. They you could report back on the very hight speed cluster connection built into every new Mac. Just a thought....

post #24 of 35
Quote:
Originally Posted by rob53 View Post

You can get a 100m 10Gbps LC-LC fiber cable for under $200 so Corning's transceivers cost ~$500 each. I know copper-to-fiber adapter boxes cost a whole lot less than that. Of course, having everything in a simple package is worth a lot but $1300 is still a lot of money, even for professional installations.

They got the lengths wrong in the article, it's $1300 for 200ft (60m), $660 for 100ft (30m). Given that the price doubles based on length doubling, I don't think it's all down to the plug components. It is expensive for a cable but it's a limited market - even less than 10Gbps Ethernet or fiber channel as it's not used in servers.
post #25 of 35
Quote:

 

That seems like a good deal for such a huge speed increase.

post #26 of 35
Quote:
Originally Posted by Marvin View Post


They got the lengths wrong in the article, it's $1300 for 200ft (60m), $660 for 100ft (30m). Given that the price doubles based on length doubling, I don't think it's all down to the plug components. It is expensive for a cable but it's a limited market - even less than 10Gbps Ethernet or fiber channel as it's not used in servers.

 

Oh I guess I got prices wrong too, $660 is pretty close to competitive with a 10gbit ethernet setup and I assume they've found a clever way to piggy back off the internal processing. Kudos to Corning.

post #27 of 35
Wonder when we will see 10 Gigabit Ethernet in a Mac...
post #28 of 35
Quote:
Originally Posted by libertyforall View Post

Wonder when we will see 10 Gigabit Ethernet in a Mac...

Based on current adoption rates and prominence of other technologies it will arrive right after FW3200.

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post #29 of 35
Quote:
Originally Posted by SolipsismX View Post

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.

I agree, video would be a good use for this but I think HDMI is going to win that battle. It's already the standard for video and I don't see TB overtaking HDMI. Maybe connections from the display to the computer but other than that I don't see TB taking off as a major I/O kinda like FW didn't. Again, don't get me wrong I like TB and I think it's great at what it does and can have many uses but for most USB is what people will use outside the professional world.

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post #30 of 35
Quote:
Originally Posted by ItsTheInternet View Post
 

 

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.

 

Isn't most fiber 50 and 62.5 micron? Would a common fusion splicer even work on this 80 micron Thunderbolt fiber?

post #31 of 35
Quote:
Originally Posted by MacTac View Post
 

 

Isn't most fiber 50 and 62.5 micron? Would a common fusion splicer even work on this 80 micron Thunderbolt fiber?

I have the same question. Why is Corning uses 80 mm fiber? From what I briefly read, the smaller size fiber actually allows faster communications over longer distances. 

 

"50 micron multimode fiber offers nearly three times more bandwidth (500 MHz·km) than FDDI-grade 62.5 micron fiber (160 MHz·km) at a wavelength of 850 nm [nanometers]." I assume this means 80 micron fiber would provide even less bandwidth.

post #32 of 35
Quote:
Originally Posted by MacTac View Post
 

 

Isn't most fiber 50 and 62.5 micron? Would a common fusion splicer even work on this 80 micron Thunderbolt fiber?

 

I haven't spliced anything in years. I'll message a colleague and get specs on their equipment.

post #33 of 35
Quote:
Originally Posted by ItsTheInternet View Post

 

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.

 

I just googled and found that fiber optic fusion splicers are a lot cheaper now ($2K-6K USD), although I don't know whether the typical units used for communication fiber would be suitable for the optical Thunderbolt cable. The one I used many years ago (which was a used one in the 5 figure range) did not require the fiber to be polished. Rather, a scribe and break method is used to cleave the fiber to create a clean, flat face. Stripping the fiber is certainly annoying, but watching a fusion splicer work is pretty awesome--you get to watch a magnified view of the fiber automatically get aligned to sub-micron accuracy, then after a bright glow, it's fused.

 

Also, you can get an OTDR for less than $10K. Although some of those Fluke kits can get quite a bit pricier.

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post #34 of 35
Quote:
Originally Posted by macxpress View Post


I agree, video would be a good use for this but I think HDMI is going to win that battle. It's already the standard for video and I don't see TB overtaking HDMI. Maybe connections from the display to the computer but other than that I don't see TB taking off as a major I/O kinda like FW didn't. Again, don't get me wrong I like TB and I think it's great at what it does and can have many uses but for most USB is what people will use outside the professional world.

 

Although HDMI is certainly ubiquitous, I wonder if it will win the battle. I realize there are other factors then pure specs that affect adoption rates, but based on specs alone, the DisplayPort/MiniDisplayPort part of Thunderbolt already win over HDMI for video. The currently available DisplayPort 1.2 spec can already handle 3840x2160 @ 60Hz w/10-bit color. Right now, HDMI tops out at 3840x2160 @ 24/30Hz w/8-bit color. HDMI 2.0 will improve things, but by the time it is widely deployed, DP will also have an updated version. DP is also royalty-free, and the full-size version has a locking connector, which is nice (the little Thunderbolt/MDP connectors make me a little nervous with the largish connector shell on that fiber though).

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post #35 of 35
Quote:
Originally Posted by RoundaboutNow View Post
 

 

Also, you can get an OTDR for less than $10K. Although some of those Fluke kits can get quite a bit pricier.

It was my own stupid mistyping in the first place. I was saying 5 figures, not 6. I'm dumb :(

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