Compact Optical Transceiver “CFP4” for 100 Gbit/s Network Systems

Data communication services based on the widelyused high performance mobile devices have been sophisticated and diversified recently. These services require increasing the data rate and enhancing the capacity of optical transmission equipment in the network systems. One of the important functions of optical transmission equipment is to transform electrical data streams to optical data signals and vice versa. Since optical transceivers built in the equipment play this role, the targets of the transceiver development can be translated from the aforementioned demands for the apparatus. The transceiver needs to speed up its data rate as the equipment is required. Given that increasing the number of transceivers on a network card makes it possible to expand the optical networking capacity, downsizing is another target for optical transceiver development. Centum gigabit Form factor Pluggable (CFP) has a 100 Gbit/s interface, which is the fastest data rate in all commercial pluggable optical transceiver form factors.(1) However, it has a large package of 144.75 x 82 x 13.6 mm and this limits the number of transceivers plugged in a network card by four. The large package of CFP blocks to enlarge the transmission capacity in 100 Gbit/s network systems. Recently, a miniaturized optical multiplexer or de-multiplexer, which is an indispensable part of the 100 Gbit/s optical transmission system, and a compact optical transmitter(2),(3)/receiver(4),(5) module, which integrates the optical multiplexer/de-multiplexer, have been reported. These modules enable the development of a small 100 Gbit/s optical transceiver. In general, pluggable transceiver suppliers constitute a group that specifies the mechanical form factor, electrical interface, and control/management functions. Centum gigabit Form factor Pluggable Multi-Source Agreement (CFP MSA), an organization for 100 Gbit/s optical transceiver standardization, published a specification for a new 100 Gbit/s transceiver called “CFP4” in August 2014.(6) CFP4 is smaller than CFP in outer shape though having the same functions and performance as CFP in terms of optical and control/management interfaces. CFP4 hardware specification premised to adopt the high speed electrical interface on 25.78 Gbit/s discussed at the Institute of Electrical and Electronic Engineers (IEEE) in parallel. This interface facilitates reducing the size by 1/6th owing to decreasing the number of high speed electrical data lines from 40 in CFP to 16 in CFP4. This paper describes a newly developed CFP4 optical transceiver for a 100 Gbit/s single mode fiber networking system incorporating an in-house compact optical transmitter and receiver module. The transceiver shows less than a quarter power consumption of CFP and contributes to expanding the optical networking capacity without any increase in power consumption.