1,720,966 research outputs found
Low-Complexity Nonlinear Electrical Equalization for Directly Modulated Laser-based Transmission Systems
No full textWe present low-complexity nonlinear equalizers designed for directly modulated laser-based transmission systems. Their bit-error ratio performance and the implementation complexity are evaluated in comparison with those of Volterra equalizers
Transmission of 107-Gb/s PAM-4 Signal over 25 km of SSMF Using O-band Commercial Off-the-Shelf DML
No full text36-Gbaud PAM-8 signal transmission in IM/DD system using pairwise-distributed amplitude shaping
No full textWe experimentally demonstrate the 36-Gbaud probabilistically-shaped PAM-8 signal transmission over 10-km single-mode fiber. The receiver sensitivity after FEC decoding and inverse distribution matcher is improved by more than 1 dB compared to uniform-distributed signals
Generation of Broadband Optical SSB Signal Using Dual Modulation of DML and EAM
No full textThe dual modulation transmitter, where both the directly modulated laser (DML) and electro-absorption modulator (EAM) are modulated, has attracted considerable attention due to its monolithic integration and high output power. This transmitter is capable of manipulating the optical intensity and phase independently since the DML and EAM serve mainly as phase and intensity modulators, respectively. Thus, the dual modulation scheme has been used to generate optical single sideband (SSB) signals. However, due to a lack of workable model applicable to high modulation frequency (e.g., >10 GHz), the data rates of optical SSB signals reported previously were all limited to <= 40 Gb/s. In this paper, we generate a 120-Gb/s optical SSB orthogonal frequency-division multiplexed (OFDM) signal using the dual modulation scheme. By using the time-harmonic model of dual modulation we have recently reported, we establish a generation procedure for broadband optical SSB signals, where the modulation conditions for DML and EAM are provided. In order to satisfy these conditions over a broad frequency range, we also propose (1) utilizing the frequency-modulation discriminator to measure the DML's chirp characteristics and (2) pre-compensating for the frequency responses of DML and EAM. In our experimental verification, we generate the 120-Gb/s SSB OFDM signal having an optical sideband suppression ratio of 19 dB. We also successfully transmit this signal over 80 km long standard single-mode fiber.
Low-Complexity, Loop-Unrolled Decision-Feedback Equalizer for IM/DD System Using PAM Formats
No full textWe propose and demonstrate a low-complexity, loop-unrolled DFE for band-limited IM/DD system. The proposed equalizer nearly doubles the maximum achievable data-rate of DFE for PAM-4 signal, but requires complexity similar to that of NRZ DFE. © 2021 OSA
Low-Complexity Nonlinear Equalizer based on Absolute Operation for C-band PAM Signal Generated by Using Directly Modulated Laser
No full textWe propose and demonstrate a low-complexity equalizer based on absolute operation for PAM transmission system implemented by using 1.55-μm DML. The proposed equalizer performs similar to the Volterra equalizer, but reduces the complexity by half
Coaxial Double Cubic Lattice Constellation for Stokes Vector Direct-Detection Receiver
No full textWe propose a new 16-ary modulation format for Stokes vector direct-detection receiver. This format incurs < 0.7-dB receiver sensitivity penalty with respect to the optimum 16-ary constellation, but the transmitter complexity is reduced significantly
Probabilistic Amplitude Shaping for IM/DD System Using Hard-Decision Decoding
No full textWe present an efficient way to apply the probabilistic amplitude shaping to intensity-modulation/direct-detection systems utilizing the Reed-Solomon hard-decision forward error correction. The shaping gain of up to 1 dB is achieved for PAM-8 signal
Transmission of 107-Gb/s PAM-4 Signal over 25 km of SSMF using O-band Commercial Off-the-Shelf DML
No full textWe experimentally demonstrate the transmission of 107-Gb/s PAM-4 signal over 25-km long standard single-mode fiber using a commercially available 1.31-μ m directly modulated laser. The limited bandwidth of laser is compensated bv using an electrical equalizer
Low-Complexity Quadratic Equalizer for DML-based IM/DD Systems
No full textWe present a low-complexity quadratic nonlinear equalizer for intensity-modulation/direct-detection system. The performance of the proposed equalizer is evaluated over PAM-4 directly modulated laser links operating in the C- and O-bands in comparison with conventional equalizers
- …
