Tianjian Zuo

Multiband Carrierless Amplitude Phase Modulation for High Capacity Optical Data Links

Short range optical data links are experiencing bandwidth limitations making it very challenging to cope with the growing data transmission capacity demands. Parallel optics appears as a valid short-term solution. It is, however, not a viable solution in the long-term because of its complex optical packaging. Therefore, increasing effort is now put into the possibility of exploiting higher order modulation formats with increased spectral efficiency and reduced optical transceiver complexity. As these type of links are based on intensity modulation and direct detection, modulation formats relying on optical coherent detection can not be straight forwardly employed. As an alternative and more viable solution, this paper proposes the use of carrierless amplitude phase (CAP) in a novel multiband approach (MultiCAP) that achieves record spectral efficiency, increases tolerance towards dispersion and bandwidth limitations, and reduces the complexity of the transceiver. We report on numerical simulations and experimental demonstrations with capacity beyond 100 Gb/s transmission using a single externally modulated laser. In addition, an extensive comparison with conventional CAP is also provided. The reported experiment uses MultiCAP to achieve 102.4 Gb/s transmission, corresponding to a data payload of 95.2 Gb/s error free transmission by using a 7% forward error correction code. The signal is successfully recovered after 15 km of standard single mode fiber in a system limited by a 3 dB bandwidth of 14 GHz.

Beyond 100-Gb/s Transmission Over 80-km SMF Using Direct-Detection SSB-DMT at C-Band

For short-reach links, direct detection offers the advantages of low cost and low complexity. Discrete multitone (DMT) is a promising format due to its high spectral efficiency, flexibility and tolerance to chromatic dispersion (CD). In this study, we experimentally demonstrate a beyond 100-Gb/s DMT transmission over 80-km single mode fiber (SMF) without CD compensation. Using dual-drive Mach-Zehnder modulator-assisted single-sideband modulation, CD-induced power fading is eliminated after direct detection. Trellis coder modulation (TCM) is used to increase the Euclidean distance of the constellation points and nonlinearity equalization (NLE) is employed to mitigate system nonlinearities. Both TCM and NLE algorithms have contributions to improve the system performance. The experimental results show that high capacities up to 122, 110 and 105 Gb/s are achieved with bit error rate at 4.5 × 10-3 for back to back, 40- and 80-km SMF transmissions, respectively. The required OSNR after 80-km SMF transmission is 34.2 dB. To the best of our knowledge, this study reports the lowest required OSNR and highest capacity for C-band direct-detection transmission over 80-km SMF.

Advanced modulation formats for 400-Gbps short-reach optical inter-connection

Besides the long-haul optical networks covering over thousands of kilometers for backbone transmission, short reach optical networks (SR-ONs) are widely deployed in metro-area for aggregation and accessing. The SR-ONs include the metro optical transport networks (Metro-OTN), optical access networks or other optical inter-connection systems with even shorter distance. As predicted, the growing bandwidth demanding from SR-ONs will be much more than that from the long-haul optical networks in the near future. Besides, there are tremendous amounts of optical terminals and end-users in SR-ONs compared with the long-haul transmission systems and thus will induce large cost and huge energy consumption. So, the power and cost efficiency should be the key consideration for SR-ONs besides the transmission performance. To improve the power and cost efficiency in SR-ONs, advanced modulations and detection techniques based on low power, low cost and integrated optical modulators should be utilized. In this paper, different advanced modulation formats have been discussed. 56Gbps PAM4, 112Gbps poly-binary and 100Gbps DMT that can be used to realize 400-Gbps SR-ONs for different applications have also been demonstrated respectively. In addition, low-cost and low-power opto-electronic components suitable for SR-ONs, the impairments induced by all kinds of defects and bandwidth limitation of opto-electronic components and the corresponding compensation techniques based on DSP algorithms have also been discussed in the experiments.

O-band 400 Gbit/s Client Side Optical Transmission Link

We present an O-band 400 Gbit/s optical client side Ethernet link with 40 km SSMF reach employing four LAN-WDM lanes, MultiCAP modulation and direct detection.

112-Gb/s duobinary 4-PAM transmission over 200-m multi-mode fibre

We experimentally demonstrated an 850-nm VCSEL based 112-Gb/s short reach interconnection system with 200-m MMF transmission employing a duobinary 4-PAM format. The sensitivity of -4.8 dBm at the 6.7% overhead FEC limit (BER=4.2×10-4) was achieved.

Towards 100 Gbps over 100m MMF using a 850nm VCSEL

Employing MultiCAP signaling, successful 70.4 Gbps transmission over 100 m of OM3 MMF using off-the-shelf 850 nm VCSEL with 10.1 GHz 3-dB bandwidth is experimentally demonstrated indicating the feasibility of achieving 100 Gbps with a single 25 GHz VCSEL.

Transmission of 112-Gb/s+ DMT over 80-km SMF enabled by twin-SSB technique at 1550nm

We experimentally demonstrate 112-Gb/s DMT transmission over 80-km SMF using low-cost direct-detection architecture based on a novel twin-SSB-DMT technique. High capacities up to 146Gb/s, 138Gb/s and 130Gb/s are achieved with BER at 4.5×1 0-3 for BTB, 40-km and 80-km SMF transmissions, respectively.

Enabling 4-Lane Based 400 G Client-Side Transmission Links with MultiCAP Modulation

We propose a uniform solution for a future client-side 400 G Ethernet standard based on MultiCAP advanced modulation format, intensity modulation, and direct detection. It employs 4 local area networks-wavelength division multiplexing (LAN-WDM) lanes in 1300 nm wavelength band and parallel optics links based on vertical cavity surface emitting lasers (VCSELs) in 850 nm wavelength band. Total bit rate of 432 Gbps is transmitted over unamplified 20 km standard single mode fiber link and over 40 km link with semiconductor optical amplifier. 70.4 Gb/s transmission over 100 m of OM3 multimode fiber using off-the-shelf 850 nm VCSEL with 10.1 GHz 3 dB bandwidth is demonstrated indicating the feasibility of achieving 100 Gb/s per lane with a single 25 GHz VCSEL. In this review paper we introduce and present in one place the benefits of MultiCAP as versatile scheme for use in a number of client-side scenarios: short range, long range, and extended range.

Single-wavelength 100Gb/s and 200Gb/s transmissions over 80km SMF based on direct detection eSSB-DMT and Twin-SSB-DMT

Base on a DDMZM, we propose and demonstrate a 100-Gb/s system for 80km SMF transmission using direct-detection eSSB-DMT. Furthermore, a twin-SSB-DMT is realized based on the same transmitter architecture and 200Gb/s over 80km SMF is successfully demonstrated with novel receiver and MIMO-array DSP.