4×4 MIMO fiber-wireless transmission based on an integrated four-channel directly-modulated optical transceiverPhotonics Research
- Di Zhang, Yao Ye, Lei Deng, Li Di, Haiping Song, Yucheng Zhang, Minming Zhang, Shu Wang, and Deming Liu
- received 07/04/2019; accepted 10/14/2019; posted 10/14/2019; Doc. ID 371612
- Abstract: In this paper, an integrated compact four-channel directly modulated analog optical transceiver is proposed and fabricated. The 3-dB bandwidth of this optical transceiver exceeds 20 GHz, and the measured spurious-free dynamic range is up to 91.2 dB⋅Hz2/3. The optical coupling efficiency (CE) is improved by using a precise submicron alignment technique for lens coupling in transmitter optical sub-assembly, and the highest CE is achieved when the oblique angle of the AWG-PLC in receiver optical sub-assembly is set to 42°. Based on the proposed optical transceiver, we have experimentally demonstrated a 6.624 Gbit/s 4×4 multi-input multi-output (MIMO) 16QAM-OFDM radio signal over 15.5 km standard single mode fiber (SSMF), together with 1.2 m wireless transmission in both uplink and downlink. To cope with the channel interference and noise of the fiber-wireless transmission system, a low-complexity MIMO demodulation algorithm based on lattice reduction zero-forcing (LR-ZF) is designed. In our experiment, 1.8 dB power penalty is achieved by using the proposed LR-ZF algorithm, compared with the commonly used zero-forcing (ZF) algorithm. Moreover, this LR-ZF algorithm has much less complexity than the optimal maximum-likelihood sequence estimation (MLSE) at a given transmission performance. These results not only demonstrate the feasibility of the integrated optical transceiver for MIMO fiber-wireless application but also validate that the proposed LR-ZF algorithm is effective to eliminate the interference for hybrid fiber-wireless transmission.