We demonstrate 50-Gb/s DMT signal transmission over 20-km SMF by using a 10G-class 1.55-mu m DML without optical dispersion compensation. Injection locking technique is introduced, which doubles system bandwidth and greatly suppresses DML chirp.

All parts of an IM/DD system are being stretched to the limit as the single lane data rate approaches 200 Gbps and beyond. We report the recent developments on the key enablers conquering this target.

This paper reports the demonstration of high-speed PAM-4 transmission using a 1.5-mu m single-mode vertical cavity surface emitting laser (SM-VCSEL) over multicore fiber with 7 cores over different distances. We have successfully generated up to 70 Gbaud 4-level pulse amplitude modulation (PAM-4) signals with a VCSEL in optical back-to-back, and transmitted 50 Gbaud PAM-4 signals over both 1-km dispersion-uncompensated and 10-km dispersion-compensated in each core, enabling a total data throughput of 700 Gbps over the 7-core fiber. Moreover, 56 Gbaud PAM-4 over 1-km have also been shown, whereby unfortunately not all cores provide the required 3.8 x 10(-3) bit error rate (BER) for the 7% overhead-hard decision forward error correction (7% OH-HDFEC). The limited bandwidth of the VCSEL and the adverse chromatic dispersion of the fiber are suppressed with preequalization based on accurate end-to-end channel characterizations. With a digital postequalization, BER performance below the 7% OH-HDFEC limit is achieved over all cores. The demonstrated results show a great potential to realize high-capacity and compact short-reach optical interconnects for data centers.

A monolithically integrated dual-DFB laser generates a 408 GHz carrier used for demonstrating a record-high single-channel bit rate of 131 Gbit/s transmitted over 10.7 m. 16-QAM-OFDM modulation and specific nonlinear equalization techniques are employed.

With the approach of the 5G era, stringent requirements are imposed on the data transport solutions, including both of the supported transmission reach and the capacity. Radio-over-fiber technologies are considered to be promising candidates to cope with both aspects, owing to the low-loss and broad-bandwidth nature of the optical fibers. Meanwhile with such optical transport solutions, signals can be collected from the distributed remote radio sites and processed in a centralized manner. In this report, we target on the digital radio-over-fiber systems, and discuss about several key technologies, focusing on the aspects of coding and transmission, which could potentially enable terabit-scale data transport.

We experimentally demonstrate the generation of 107-Gbit/s net-rate optical discrete multitone signal using a 1.5-mu m single-mode vertical cavity surface emitting laser (VCSEL) with modulation bandwidth of 22 GHz. Utilizing a nonlinearity-tolerant channel equalization algorithm for digital signal processing, total net-rates of 726.6-Gbit/s over 2.5-km dispersion-uncompensated 7-core fiber and 533.1-Gbit/s over 10-km dispersion-compensated 7-core fiber below 7% overhead hard-decision forward error correction limit have been experimentally achieved with a 1.5-mu m VCSEL-based intensity-modulation direct-detection system. The features of the 1.5-mu m single-mode VCSEL, 2.5-km/10km multi-core fibers, and fan-in/fan-out modules are presented. Besides, the Volterra series-based nonlinearity-tolerant channel equalization algorithm, which improves the signal-to-noise ratio with more than 5 dB, is mathematically described and experimentally validated. The results have demonstrated that 1.5-mu m single-mode VCSEL and multi-core-fiber-based transmission can be a promising candidate to solve the capacity challenges in short-reach optical interconnects.

To support massive deployment of broadband radio applications, such as 5G and high-definition videos for terrestrial televisions, large system capacity and high spectrum efficiency are highly demanded in radio over fiber (RoF) systems. In this article, we propose a terabit digital RoF system capable of providing high-speed transmission, where multicore fiber (MCF) is introduced for the access segment between the central unit and remote unit. Two key technologies that greatly enhance system capacity and spectrum efficiency, namely MCF enabled self-homodyne detection and compressed quantization, are demonstrated.

By using a monolithically integrated dual-distributed feedback (DFB) laser chip attached to a photomixing uni-Travelling carrier photodiode (UTC-PD) with a THz antenna, single-channel THz photonic-wireless transmission system with a net rate of 131 Gbit/s over a wireless distance of 10.7 m has been achieved.

By employing enhanced DPCM, 15-Gbaud PAM4 digital mobile fronthaul is experimentally demonstrated to support 122 LTE-A channels with up to 4096QAM. Compared to PCM based CPRI, the supported number of channels increases 5 times and EVM is obviously improved.

100 Gbps/λ/core PAM-4 transmission is successfully demonstrated over 1-km and 10- km single mode 7-core fiber links, enabled by directly modulated 1.5-μm single mode VCSEL of 23 GHz modulation bandwidth with pre- and post- digital equalizations.