Fig. 1: Concept and architecture of the FNT-SHCD scheme.
From: Coherent optical interconnects using Fermat number transform and hollow core fibre
This scheme is designed to address the power consumption and latency challenges faced by conventional coherent technologies in next-generation intra-/inter data centre networks. a Intra-/inter data centre optical networks undertake large amounts of data traffic, supporting the internet of vehicles, cloud services, and AIGC training and application processes. b Architecture of conventional single-carrier coherent technology in DCNs. c Power consumption distribution of the coherent optical module. Others mainly involve power conversion loss. d Link latency distribution of the conventional coherent optical module using SSMF. Frame time: the time used to transmit and receive a MAC frame; Switch: Ethernet switches. e The proposed FNT-based transmitter (Tx) DSP strategy. f The proposed FNT-based receiver (Rx) DSP strategy. The SHCD structure eliminates FOC and CPR algorithms. The use of NANF and DSCM technologies eliminates the CDC block and unlocks the FNT-based AEQ algorithm. By integrating FNT into Nyquist filtering and AEQ blocks, the ultra-simple DSP flow is achieved. g The FNT-SHCD architecture for bidirectional transmission: a bias point offset is adopted to insert the LO component into the guard interval of the DSCM signal, and FBG and OIL are used to achieve LO regeneration. h The internal microstructure of the NANF with five annular glass tubes. FNT: Fermat number transform; AIGC: artificial intelligence-generated content; DCN: data centre network; DP IQ Mod.: dual polarization in-phase/quadrature modulator; SSMF standard single-mode fibre, LO local oscillator, ICR integrated coherent receiver, DSP digital signal processing, FEC forward error correction, TIA trans-impedance amplifier, ADC analogue-to-digital converter, DAC digital-to-analogue converter, MAC media access control, SHCD self-homodyne coherent detection, FOC frequency offset compensation, CPR carrier phase recovery, NANF nested anti-resonant nodeless fibre, DSCM digital subcarrier multiplexing, CDC chromatic dispersion compensation, AEQ adaptive equalization, PRBS pseudo-random binary sequence, SRRCF square root raised cosine filtering, SRRCMF square root raised cosine matched filtering, DSC Mux/Demux digital signal subcarrier multiplexing/demultiplexing, FBG fibre Bragg grating, OIL optical injection locking, DFB distributed feedback.
