Coherent Transceiver for High Speed Optical Communications: Opportunities and Challenges

With the emergence of new markets for coherent optical transponders, new challenges need to be addressed. Coherent optical modems have fast become the standard transport solution in the telecommunications industry for medium and long reach applications and are gaining momentum in shorter reach applications. In this paper, we highlight some of the technical challenges stemming from the different application spaces and how the requirements from each market segment will affect the design of subcomponents of optical transponders, in particular for analog electronics and for optical components and sub-assemblies. In particular, we will present how key technologies such as CMOS, Bi-CMOS, III-V and Silicon Photonics (SiP) will help alleviate some of the system-level challenges.