Summary: With people more and more focusing on the economic efficiencies of 40G VS 100G, If more affordable 100G coherent design appears, then is there market space for 40G?
“If the 40Gbps module on the first class of market, then the 100 Gbps is on the fourth”, ECI Telecom fiber network company vice president Oren Marmur says. 10G market has experienced several evolutions until today, from the large 300-pin package (LFF) to a 300-pin small outline package (SFF) and then the smaller fixed wavelength pluggable XFP, finally evolved into today’s tunable XFP. “40 Gbps is in the same states of 10 Gbps markets in a couple of years ago, when each vendor has their different packages and modulation schemes.”
Opnext company supplies four types of 40 Gbps swapping device: Dictionary, DPSK, continuous mode DPSK variants and DQPSK. According to Ovum survey, duobinary is lowest cost, followed by DPSK. But swapping vendors is facing the next step to go, whether to make a bet on the 40 Gbps DQPSK or DP-QPSK designs?
However, material cost is only one of the bottlenecks, optical performance is more important constraints. DQPSK has excellent dispersion properties, but if used simultaneously with 10 Gbps, you must manage well 40 Gbps coherent channel locations.
Another concern is the 100Gbps module. DP-QPSK is recognized the best 100 Gbps modulation scheme, while taking into account the 40 Gbps and 100 Gbps coherent design commonality between, the relative cost advantage of each will become the winning factor. Finisa Rafik Ward, vice president of marketing, said the concern is the 40G VS 100G economic benefits. “If more affordable 100G coherent design appears, then is there market space for 40G?”
At the same time, designers are constantly shrinking the size of the existing 40 Gbps module dedicated to significantly increase its system capacity. 7 x 5 – inch 300-pin LFF Transponder need to configured with the cable card with self, so a 40 Gbps link line card requires the use of two systems: one for the client interface interface for the short-range arrival rate, the other is for the line side swapping device.
Mintera is currently developing the smaller 300-pin MSA DPSK transponder to make a line card capable of carrying two 40 Gbps interfaces. The current design is that each line card composed of a three bay racks. With the new line card design, since each carrier can carry 16 40 Gbps links and each system has a capacity of 1920 Gbps, the total system capacity can be doubled. Equipment suppliers can be also used smaller pin-compatible 300-pin MSA on an existing line card to reduce the costs.
Openext senior technical marketing manager Matt Traverso also stressed the importance of compact swapping device: “Although this is not yet mature, this will be a war on the modulation mode.”
Another factor that drives the development of the transponder is the electrical interface it used. 300-pin MSA-based 16 2.5 Gbps channels SFI 5.1 interfaces, while 40 GbE/100 GbE were using 10 Gbps interfaces, as many framers and ASIC vendors done. Because 300-pin MSA is not compatible with that, long-distance transmission adopting Channel 10 Gbps electrical interfaces will need the use of the new plug-in MSA.