Standards Development

Scope

This International Standard provides measurement methods of common-mode rejection ratio of optical coherent detection device in high-speed RoF systems as well as high-speed optical signal transmission systems. In addition, these methods are also effective for the estimation of the detailed frequency response of the common-mode rejection ratios and O/E conversion efficiency.

Purpose

For effective conversion from an optical signal to electrical signal, a frequency response of the conversion in an optical-to-electrical converter should be carefully evaluated and estimated. IEC 62803 Ed 1.0 provides a useful method for measurement of the frequency response. Nowadays, an optical coherent transport system has been spread in the world for achieving an optical fibre communication capacity of 100 Gbit/s/ch. This technology is based on an optical IQ detection with digital signal processing techniques, and therefore, an optical coherent receiver also has a feature of IQ separation in an optical domain. The implementation of the function will show great possibility of the direct IQ conversion in optical-to-radio direct conversion schemes. In general, a laser lightsource has relatively large linewidth (phase noise) rather than that in a radio domain. A noise suppression method based on a balanced detection is a key for rejection as a commonmode noise. A parameter of a common-mode rejection ratio plays an important role for specification of fabricated devices; however, there is no standardized technique for measurement of the common-mode rejection ratio.

TC103 WG6 meeting held in 2018 at Busan, Korea, 2019 at Shianghai, China and 2020 in virrual, there were a lot of discussion regarding the current and future applications related on radio over fibre systems. In the scenarios, a coherent receiver, which implies for an optical coherent transport system in general, will play an important role for high-efficiency optical-to-electrical conversion with large common-mode rejection ratio.