# The Firmware Design and Implementation Scheme for C Form-Factor Pluggable Optical Transceiver +
## 5 Conclusions  
In this paper, we proposed a 100 Gbps CFP firmware design based on the MSA standard and verified its utility by evaluating the actual implemented firmware in a testbed. In the proposed method, the communication interface is implemented using an external host and the internal operations of the CFP are performed using an FPGA and MCU, and it was ported to actual CFP hardware. The validity of the proposed firmware design technique was verified through the correct operation of the CFP transceiver according to the MSA operation management standard. Moreover, we proposed a method of calculating DDM considering temperature and high accuracy. the testbed results confirmed that the DDM accuracy is excellent, based on comparison of the performance of the proposed firmware with that of the CFP transceiver of an existing product. This paper also proposed memory design and memory access technic for stable memory access and operation of optical transceiver and confirmed safety through testing.  
The proposed technique can also be used for CFP-type optical transceivers such as CFP2 or CFP4. The overall bandwidth of the optical transceiver depends on the number of optical components or channels being used. This approach was designed considering the expandability of channel so that it can be applied to the development of 200/400 Gbps CFP-type modules such as CFP8 in the future. Applying the techniques proposed for high-bandwidth CFP types requires only specific modifications according to optical components and optical driver ICs.  
The proposed firmware method satisfies the requirements of the standard but does not consider optional conditions such as firmware remote update. The MSA standard document describes the mutual procedure between the host system and the optical transceiver for the remote firmware update of the optical transceiver. The host systems using optical transceivers should support to send commands according to standard procedures for remote downloads. Therefore, in future research,  
\begin{table}
\begin{tabular}{l l} \hline \hline
**Advantage** & **Explanation** \\ \hline Scalability & - Flexible expansion of up to 16 channels \\  & - Flexible external chip can be added \\ \hline Stability & - CFP memory block and operating functions \\  & separated by hardware module \\ \hline Utility & - Easy firmware update and CFP control through vendor IO \\ \hline \hline \end{tabular}
\end{table}
Table 4: Advantages of Proposed Design.  
Figure 17: Graph of Rx Power DDM Accuracy Comparison.  
the remote firmware download procedure will be tested by implementing not only optical transceiver but also host-side functions following standards. In addition, various data driver ICs are being released as the data transfer rate is increasing to 200/400 Gbps. We therefore plan to design and implement the interface driver accordingly.  
Design and Implementation J.-W.K.; formal analysis S.-H.K.; hardware S.-M.S.; writing--review and editing D.-S.K. All authors have read and agreed to the published version of the manuscript.  
This research was supported by Basic Science Research Program and Priority Research Centers through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2019R1I1A1A01063895, 2018 RIA6A1A03024003).  
The author would like to thank the Co. ARTECH for the the data provided.  
The authors declare no conflict of interest.