The Lowly Optical Connector Gets a Makeover
Release time : 2012-05-04 view count : 286 次It took decades for someone to figure out that a ketchup bottle works better upside-down. Now Arrayed Fiberoptics Corp. thinks it's found a similar breakthrough for optical connectors.
On Wednesday, the company announced a new design that's arguably the first major advancement for connectors in 30 years.
Arrayed will be showing off the new design at the Conference on Lasers and Electro-Optics (CLEO) in San Jose, Calif., next week.
Arrayed
does pretty much what its name suggests: It sells 2D fiber arrays and
2D collimator arrays, connecting multiple fibers to optical equipment.
The
company does business from the corner of a small industrial park in
Sunnyvale, Calif., in a two-room shop that, for the moment, doesn't even
have Arrayed's name on the door. (It's not as if passers-by are going
to come in and browse.)
But it's been profitable
since 2006, says president and founder Benjamin Jian, and continues to
turn out products with a staff of just eight.
Connectors
are little plastic-and-ceramic widgets used for connecting one optical
fiber to another. One end of each fiber snaps into either side of the
little rectangular connector; think of them as highly precise Lego
blocks.
They're not especially glamorous, but
they're vital to optical systems in general and have helped make an
empire out of a company like Tyco, now called TE Connectivity (NYSE: TEL). About 500 million optical connectors ship every year, Jian says.
Over
the decades, connectors have been improved in small nudges -- they've
gotten smaller, for instance. But the basic design has stayed the same:
Specifically, the fibers actually touch. Each one has tip that's
polished into a convex shape so that the fibers make contact, like two
circles kissing.
What's wrong with
that, in Jian's mind, is that the insertion loss -- the light that
doesn't make it to the other side, essentially -- varies randomly. If
you unplug a fiber from a piece of equipment and then plug it back in,
you might get a different insertion loss. That's normal, and engineers
have learned to shrug it off.
Jian ran into this
issue in 1998 as an engineer at another company, when he worked on a
device that had 40 connectors. "I wanted to do a good job, so I checked
and checked, and never got repeatable results," he says. "I went to my
manager, and he said, 'Don't bother. This is typical of connectors.'"
So,
Jian has created a non-contact connector. The fibers are still convex,
but recessed, so that they don't meet. There's an air gap between them.
The
reason connectors aren't made this way normally is because some of the
light coming out of the transmitting fiber will actually reflect back,
disrupting the light source. It's not a lot of light -- about 4 percent,
Jian says -- but that's well above the acceptable level of one part per
million.
To get around that, Arrayed uses an
anti-reflective coating for the fibers. The resulting non-contact
connector produces more consistent results and happens to have lower
insertion loss in the first place.
When Light Reading visited
Arrayed, Jian gave a not-so-scientific demonstration, simply plugging
and unplugging connectors repeatedly into a test bed. (It's so easy,
even a journalist can do it.) A high-end, off-the-shelf connector showed
insertion losses of 0.09 dB down to 0.04 dB with no particular pattern;
it's not as if the number got better or worse with repeated tries.
Arrayed's non-contact connector always showed insertion loss of 0.04 dB,
sometimes dipping down to 0.03 dB.
The air gap has
another advantage: The glass doesn't wear down over time. Jian compares
it to a vinyl record, which gets a little bit damaged with every touch
of the phonograph needle. (Kids, ask your parents.) The non-contact
connector is more like a compact disc (hopefully without the risk of fungal rot).
Aside
from the coating and the air gap, the non-contact connector isn't
particularly radical. Each fiber slips into a ceramic ferrule that holds
it in place, and then the two fibers are slid into a split ceramic
sleeve where the ends meet (without touching, of course).
It
looks like a normal connector. In fact, the samples in Arrayed's lab
were even the same color as the normal connectors, distinguished only by
numbers penciled on.
So, would anybody care about a new type of connector? Light Reading ran the idea by Jordan Chaney, an engineer with Fujitsu Network Communications Inc.He
says it's interesting enough on the surface to check out, although he
was a little worried about dust and other contamination invading the air
gap.
But the insertion loss does seem good and the idea does seem novel, he says.
Arrayed
has built only hundreds of the non-contact fiber connector so far. Jian
and his crew do the work themselves, running machines that polish
multiple fibers at once and contracting the antireflective coating
production to a thin-film manufacturer. If volumes get big enough, Jian
would like to start using overseas contract manufacturers.
If it all works out, Jian might pursue the thing that made him rethink connectors in the first place.
"I
have a bigger dream. I want to create a connector that has 100 inputs
and 100 outputs," he says. "That doesn't exist, especially in a
single-mode version." He admits, though, that a single-fiber connector
is a much bigger market.[1]
[1] Craig Matsumoto, Managing Editor, Light Reading. [Online]. Available: visit Light Reading. [Accessed: 04-May-2012]