VerZicheng Wu, Sida Li, Zhiping Huang , Fangqi Shen and Yongjie ZhaoCollege of Intelligence Science and Technology, National University of Defense Technology, Changsha 410073, China; [email protected] (Z.W.); [email protected] (S.L.); 18:1 PEG-PE manufacturer [email protected] (F.S.); [email protected] (Y.Z.) Correspondence: [email protected]: Chromatic dispersion equalization (CDE) in 1-EBIO Membrane Transporter/Ion Channel coherent optical communication systems is particularly critical for subsequent digital signal processing (like frequency offset estimation and carrier phase recovery). Numerous strategies described inside the published literature aren’t satisfactory when the signal bandwidth is limited. This paper proposes a way of applying singular value decomposition least square (SVDLS) to acquire the optimal tap weight on the CDE filter as well as a method to introduce the adaptive mutation particle swarm optimizer (AMPSO) algorithm in to the CDE. We show that the two proposed approaches are determined by the most beneficial approximation of the frequency domain response with the made and excellent CDE filter. Compared using the regular CDE system, which needs to be implemented inside the complete frequency band, the two procedures may be implemented inside the narrow frequency band. The simulation shows that the successful bandwidth in the baseband signal is limited by squared-root-raised-cosine (SRRC) pulse shaping using a roll-off factor of 0.25 in different modulation formats (DP-QPSK, DP-16 QAM, DP-64 QAM) when the amount of taps of the filter is 131, that is 37.5 less than the complete frequency band. The made filter is superior to the existing filter with regards to filtering effect and implementation complexity. Search phrases: coherent optical communication; chromatic dispersion; AMPSO; SVDLSCitation: Wu, Z.; Li, S.; Huang, Z.; Shen, F.; Zhao, Y. Chromatic Dispersion Equalization FIR Digital Filter for Coherent Receiver. Photonics 2021, 8, 478. https://doi.org/ ten.3390/photonics8110478 Received: 16 September 2021 Accepted: 22 October 2021 Published: 27 October1. Introduction With the expansion from the 5G network construction scale plus the revolutionary development of the industrial net, the construction in the optical network is marching towards greater speed, massive capacities, and extended distances [1]. In the case of long-distance transmission systems, such as submarine optical cables, the accumulated transmission loss, nonlinear effects, and chromatic dispersion (CD) result in the deterioration of high-speed optical fiber program efficiency. The erbium-doped fiber amplifier (EDFA) is introduced to overcome transmission loss and the optical energy is monitored to suppress the nonlinear effect. The CD has turn into the significant obstacle to upgrading the optical network business [2]. Within a wide-band technique (64 GBaud or larger), the inter-symbol interference (ISI) brought on by CD extends over more than 150 symbols following 250 km of fiber transmission and preclude long-distance transmission with out proper chromatic dispersion equalization (CDE) [3]. CD has been correctly compensated in the optical and electrical domains. Within the optical domain, equipment with significant negative CD is mainly utilized for compensation [4]. With the improvement of high-speed analog-to-digital (ADC) converter and coherent detection methods, digital coherent receivers can compensate for substantial amounts of accumulated CD within the electrical domain at negligible price through digital signal processing (DSP) approaches [5]. A series of methods for achievin.