Single-wavelength bidirectional 4-core MCF self-homodyne coherent link.

In this paper, we propose and demonstrate a single-wavelength bidirectional self-homodyne coherent (SHC) link over a 125 µm cladding diameter based multicore fiber (MCF). The 4-core MCF based link efficiently uses two cores for each direction of propagation. In either direction, one of the cores carries a dual-polarized 40 Gbaud 16-QAM signal, and the second core carries a 40 Gbaud 16-QAM signal in one of the polarizations with the carrier multiplexed in its orthogonal polarization. Thus, a 480 Gbps data transmission rate is achieved in either direction of propagation over the 12.8 km long 4-core MCF. The SHC link operates at the same wavelength for each of the directions and eliminates the need for reconfigurable transceivers. A low-cost DFB laser (linewidth = 1 MHz) is used to demonstrate the bidirectional link, and the bit error rates (BERs) of the received signals are <5.5×10-4. With higher baud rates, this approach can meet the capacity requirements of future short-reach data center interconnects (DCIs).

Adaptive electro-optic equalization in low-power coherent-lite interconnects.

In this paper, we propose an adaptive electro-optic equalizer for short-reach interconnects employing coherent modulation and detection. The equalizer consists of two main components: an optical equalizer filter and an electronic controller. The equalizer filter compensates for the linear dispersion occurring in the channel, while the electronic controller adaptively determines the weight coefficients of the equalizer. To achieve adaptive adjustment, we have introduced a random search algorithm. Extensive simulations have been conducted to evaluate the performance of the equalizer in a 120 Gbaud homodyne coherent link, and the results show great promise. The proposed equalizer has the potential to greatly improve the overall power efficiencies of receivers in short-reach coherent-lite interconnects.