Compact Optical Receivers for Coherent Optical Communication

Communication traffic is increasing continuously along with the expansion of video streaming service and the popularization of smartphones and other mobile devices requiring high-speed, large-capacity transmission. Digital coherent optical communication technology using multilevel modulation formats has already been used for long haul systems and is now attracting attention as a means of long-distance, large-capacity optical communication that meets the demand for the increase in communication traffic. To expand the application of this technology to metro systems in the future, it is critical to downsize the optical transceivers and thereby increase port density and transmission capacity per port. A CFP2-ACO*1 optical transceiver(1) complying with the Optical Internetworking Forum (OIF)*2 implementation agreement is drawing particular attention as a promising device that can meet the above requirement. Since 2013, Sumitomo Electric Industries, Ltd. has continued to develop compact optical receivers(2),(3) comprising InP-based photonic devices for coherent optical communication applications. We have recently developed a further downsized optical receiver that can be installed in the CFP2-ACO optical transceiver. The new optical receiver conforms to the OIF implementation agreement for micro-intradyne coherent receivers (Micro-ICR).*3, (4) This paper discusses the design and principal characteristics of the new optical receiver.