The debate whether there is a market for 100G direct detection systems which are essentially Non Coherent is interesting. ADVA is on one side while the rest of industry on the other side. ADVA has been strongly advocating the need for 100G direct detection trasnponders that can cater to the need of what they call 40 KM to 500 KM market segment. This segment is essentially the metro market where cost matters and that is where the DD (Direct Detection) systems cost wise are much better than the Coherent systems. Coherent systems also generate more heat and need more power – A point highlighted by ADVA.
ADVA is almost alone in the camp that is advocating the DD systems, while the rest of the market is on the other side. Coherent market thinks that there is an ecosystem for 100G coherent system which will be affected if a competing technology comes in. The whole idea of having one technology is to have economy of scale; once everyone is developing same technology the costs will bring down automatically. That there is no need for a competing technology specially when Coherent systems can give you some low-cost Metro flavours though not at a cost at which DD system sells.
As an operator, I do have concerns about the cost of Coherent 100g but then there are larger industry interests and that is creating an ecosystem for Coherent 100g components; without the industry focusing on a single technology, there would be a competition for the market in the metro area between the direct detection and Coherent technologies. This of course does not augur well for the industry in the long-term. I am a firm believer that the cost of coherent will go down in future, if all of us focus on it. So what do you think about the Coherent versus DD debate, let me know !