Optical/IP Networks

WaveSplitter Gets Dynamic Over DWDM

AMSTERDAM -- ECOC 2001 -- When WaveSplitter Technologies Inc. unveiled a couple of joint development projects earlier this week, some of its competitors poured cold water on the announcements, saying the products coming out of the partnerships were nothing new.

Now it looks as though WaveSplitter was right all along. Its projects with Infineon Technologies AG (NYSE/Frankfurt: IFX) and Gemfire Corp. are pushing the envelope on integrating electronic and optical devices in compact modules (see Infineon, WaveSplitter Demo Monitor and WaveSplitter, Gemfire Demo VOA Mux).

WaveSplitter is targeting the same goal as many of its competitors -- adding ways of monitoring and adjusting light power to the mux/demux modules used in DWDM systems -- but it's going about it in a different way. Rather than tackling the whole project itself, it's partnering with companies with established expertise in these technologies.

Wavesplitter itself reckons it's got some pretty cool (low insertion loss) Arrayed Waveguide Gratings (AWGs), one of the main technologies for making mux/demux components. Infineon already makes arrays of detector elements for monitoring light power. And Gemfire has an innovative approach to making arrays of variable optical attentuators (VOAs) (see Gemfire Comes Out Blazing). VOAs are used to adjust the light power in adjacent channels in DWDM systems, to reduce the likelihood of interference.

Right now, Wavesplitter and Infineon have made a joint product by glomming together a WaveSplitter AWG and an Infineon detector array, using a process called "flip chip bonding." Similarly, Wavesplitter and Gemfire's product is an AWG and VOA array linked together using fibers. The company hopes to shift to a bonded interface sooner or later.

Prototypes of these modules, which can support as many as 40 DWDM channels, are on show at WaveSplitter's booth at the ECOC exhibition. The AWG with power monitoring is being prepared for Telcordia reliability testing. WaveSplitter expects to ship engineering samples this quarter and go into commercial production in the first quarter of 2002.

"The next product advance would be to put all three [devices] together in a single module," says Bill Diamond, WaveSplitter's president and CEO.

The big issue that's driving AWG developers like WaveSplitter to come up with these products is the concept of dynamically reconfigurable networks. This is "point and click" service provisioning -- enabling service providers to set up and tear down light paths across optical backbones from a remote console without having to send engineers out into the field to manually reconfigure or adjust equipment.

Although this sounds great in theory, it's tough to do in practice because every path has different optical characteristics. As a result, the power needs to be adjusted on every link to optimize performance and prevent problems in adjacent paths. To make matters even more complicated, this has to be done for the primary and the backup route on protected connections. Otherwise, switching over to the backup route when the primary goes down would propogate problems throughout the network.

"As soon as you begin to route traffic dynamically, you have a situation where you need to balance channel power on a continuous basis," says Diamond. In other words, power monitoring and adjustment needs to be built into DWDM networks at every node.

As noted, most AWG manufacturers are developing products that address this requirement but are doing it in different ways. And right now, WaveSplitter's approach appears to be paying off.

First off, let's take a closer look at its joint product with Infineon. At least two other startups -- Bookham Technology PLC (Nasdaq: BKHM; London: BHM) and Kymata Ltd. (now part of Alcatel Optronics [Nasdaq: ALAO; Paris: CGO.PA]) -- also have products that integrate AWGs and power monitors.

However, Bookham and Kymata have made different sorts of devices. Both of them have made separate power monitoring devices using their AWGs. But they haven’t made a mux/demux widget with built-in monitoring, which is what WaveSplitter has done.

Built-in monitoring reduces costs considerably, according to WaveSplitter. It also means that power monitoring just becomes part of the network; it’s not something that has to be added as an afterthought, possibly at much greater expense.

The downside of WaveSplitter’s approach might be that the bonding process between its AWG and Infineon’s detector array is a possible source of reliability problems -- particularly as its AWG has to be kept at a constant temperature to work properly. Bookham and Kymata don't have this issue, because their power monitoring has been integrated into the same piece of semiconductor material as the AWG.

WaveSplitter's monitoring might also fall short of what some service providers will require. Many of them are likely to ask for optical signal-to-noise ratio monitoring as well as power monitoring, according to experts, and WaveSplitter can, so far, only do the latter.

Now let’s look at WaveSplitter’s other joint development project, with Gemfire: to make a VOA multiplexer.

Here again, a bunch of AWG manufacturers -- including NTT Electronics Corp. (NEL), JDS Uniphase Inc. (Nasdaq: JDSU; Toronto: JDU), Lightwave Microsystems Corp., and Bookham -- already have such modules. What happens inside the modules, however, differs from one company to the next. JDS, for example, simply links together a separate AWG and VOA with fiber, while Bookham integrates both devices in a single piece of silicon.

As already noted, WaveSplitter uses fiber to link its AWG with Gemfire's VOA but is hoping to move to a bonded interface sooner or later. This isn't taking integration as far as Bookham but enables WaveSplitter to use the most appropriate materials for each device: silica-on-silicon for its own AWGs and polymer for Gemfire’s VOA arrays, according to Diamond. “We don’t need to be hung up on the fact that different materials are required,” he says.

The upshot, according to WaveSplitter, is much better performance than competing products. It cites an attenuation range of 25 decibels for its joint development with Gemfire, adding that existing products from other vendors typically have a much smaller, 10 dB range. WaveSplitter also cites low power consumption (6 watts) and low polarization dependent loss (0.5 dB).

— Peter Heywood, Founding Editor, Light Reading
iamnoone 12/4/2012 | 7:46:30 PM
re: WaveSplitter Gets Dynamic Over DWDM ---- quote from article
When WaveSplitter Technologies Inc. unveiled a couple of joint development projects earlier this week, some of its competitors poured cold water on the announcements, saying the products coming out of the partnerships were nothing new.

Now it looks as though WaveSplitter was right all along....

I'm confused about this... I would tend to concur with the competitors who claim this is nothing new (although I am not a direct competitor myself, not being one of the companies listed in the article).

Everything that was done with Wavesplitter's AWG can be done with almost any other AWG out there, especially the fiber-connection with Gemfire's VOA. These partnerships would only be worth talking about if any of the individual components had either higher performance or lower cost. Of course Wavesplitter claims their AWGs have lower insertion loss, but that remains to be proven.

Bottom line -- the integration doesn't seem like much to shout about unless the individual components themselves are remarkable.
Physical_Layer 12/4/2012 | 7:46:15 PM
re: WaveSplitter Gets Dynamic Over DWDM Regarding AWG losses, I'm curious what people feel is state of the art these days. Obviously there are more parameters to consider than simply loss, so let's assume a basic Gaussian device. What is typical for a leader in this field? 5dB? Less? I think Hitachi Cable has some very low figures and is definitely one of the leaders in the space.
realoptics 12/4/2012 | 7:46:09 PM
re: WaveSplitter Gets Dynamic Over DWDM What Wavesplitter has done with others is nothing new, what insertion loss they got is nothing compare to other AWGs, do not even need to mention other results from the other type of technology, such as BaySpec's(Fremont, CA, www.bayspec.com) Chromatica series 40 channel mux/demux, which has on aveergae 2.5 dB insertion loss and is also athermal(no heaer required for the full working range of -5 C to 70 C). The good news it is not based on AWG so its yield is very high. It is beleived all the AWG guys, especially Wavesplitter's are nothing but hype.

This market needs more real, practical products, rather than hype

newguy 12/4/2012 | 7:46:08 PM
re: WaveSplitter Gets Dynamic Over DWDM I belive that a couple of months ago, Wavesplitter was buying AWGs from NEC, putting their label on the AWG and selling as its own. Can you verify this? Is it still true? NEC is an investor in Wavesplitter. The selling point for the NEC AWG was footprint. NEC had perfected the process so as not to need (??? forgot what) which should have made it cheaper in addition to smaller.

Rumor was that NEC took the AWG and other items from CEL, one of their traditional American sales channels, and gave them to Wavesplitter to sell.

Peter if it's true, don't you just love this kind of info?
winthegame 12/4/2012 | 7:46:05 PM
re: WaveSplitter Gets Dynamic Over DWDM I urge readers to check out the BaySpec product on their website.

Insertion loss is 4 dB, not 2.5 dB. I'll bet the price is quite a bit higher than AWGs of similar performance. Adjacent Channel crosstalk is touted to be 35 dB, however, it looks like this value is stated at the channel center wavelength, which is not useful and really not consistent with the conventions used by experienced DWDM suppliers.

In order for a crosstalk value to meaningful, it must be characterized over some useable bandwidth, and, in such case, the Chromatica productlooks quite marginal.

Athermal is nice if you can prove it reliable and also achieve competitive optical performance. Bayspec has a long way to go it looks to me....

Sorry realoptics, but your account of the Bayspec's Chromatica is "realhype".......
realoptics 12/4/2012 | 7:45:54 PM
re: WaveSplitter Gets Dynamic Over DWDM Wavesplitter does not know yet how to produce their chips, your are probably right on where they get their chips. People in Fremont knows well how capable Wavesplitter is.
dc_optics 12/4/2012 | 7:45:53 PM
re: WaveSplitter Gets Dynamic Over DWDM Word on the street is that Cogent is headed down the same road as Pathnet. Deju Vu seeing that Pathnet and Cogent have the same CEO.
realoptics 12/4/2012 | 7:45:52 PM
re: WaveSplitter Gets Dynamic Over DWDM Folks:

winthegame probably works for Wavesplitter, so he should know better where the chips come from.

I have learned the reason BaySpec put 4.0 dB insertion loss is because that they area group modest people thus they do not put HYPE anywhere. Plus, they are busy on working products rather than modfying their website constantly like what some other companies do in Fremont.

The device we have tested has 2.5 dB insertion loss and cross talk is better too.

By the way, how the hell you can bet their cost is higher than AWG's with similar performance, and even though assuming the insertion loss at 4.0 dB, we know there are NOT many AWGs can achieve that low insertion loss anyway, and certainly not with Wavesplitter's AWG devices. Tell me you have a customer on your AWGs, winthegame, remeber, you work for Wavespliter, formerly AFO(rumor says people called you guys UFO, may be the reason to change name). How do you know other people have long way to go, you can not make judgement on that without knowing any facts? They are shipping in qty of their athermal devices, and better yet, it is Bellcore 1221 qualified!

The company is started for one reason only, using their Chromatica technology to compete with AWG on athermal, low cost high channel count demux/mux, the price per chanel is much lower than that of AWG.

Winthegame, this is not a game, it is for real optics, tell me if you want to try a real device from BaySpec, I could call my classmate there to send you one free, the only condition for me to do that is, if I was mistaken on that you work for Wavesplitter, I would apologize to being hard on you if you do not work there.

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