56  Gb/s multi-band CAP for data center interconnects up to an 80  km SMF

Multi-band CAP for Next-Generation Optical Access Networks Using 10-G Optics

“…1, which is similar to that presented in [17]. The transmitter offline DSP includes a serial-to-parallel (S/P) convertor, a Levin Campello algorithm-based bit/power loading module needed at the beginning of the communication, differential QAM encoders varying from differential binary phase shift keying (DBPSK), DQPSK to partial differential QAM-32 to convert bit streams into complex symbols, orthogonal square-root raised cosine (SRRC) shaping filter pairs containing inphase(I) and quadrature (Q) channels with a roll-off coefficient of α = 0.1 at its assigned center frequency k f (k = 1, 2, …, N), and an addition operation to add symbols of all sub-bands.…”

“…On the contrary, multi-carrier [15,16] and/or multi-band schemes [17,18] featuring enhanced spectral efficiency and flexibility by fully leveraging advanced digital signal process (DSP) can support high capacity and long reach without altering the optical infrastructure. In addition, simple asymmetrical optical filtering by utilizing the deployed wavelength division multiplexing (WDM) multiplexers (MUXs) and de-multiplexers (De-MUXs) or Arrayed waveguide gratings (AWGs) is advantageous for multi-band or multi-carrier systems to increase fiber dispersion tolerance [16][17][18]. As indicated in [7], such optical filtering approach can achieve stable performance in field trial demonstrations.…”

“…Although training symbols-assisted phase tracking and estimation in the receiver side can recover the signal [18,21], it introduces overhead and additionally high frequency non-data dependent jitter beyond the phase tacking loop bandwidth cannot be tracked or compensated. We have proposed partial differential quadrature amplitude modulation (QAM) encoding and decoding schemes together with multi-modulus algorithm (MMA) equalization to efficiently recover multi-band CAP signals in a completely blind manner [17,19]. Based on zero-overhead signal recovery DSPs, an cost-effective optical amplified 40 Gb/s lane rate multi-band CAP LR-PON system was experimentally demonstrated using 10-G class transceivers only and it can offer excellent link power budgets [19].…”

“…The OBPF has a filtering profile very similar to a 50-GHz grid WDM MUX [23]. The OBPF is tuned to generate a frequency offset between the laser frequency and the MUX center frequency, leading to a VSB multi-band CAP signal [17][18][19]. The VSB signal can significantly increase the tolerance to fiber CD compared to the double sideband (DSB) case.…”

Data information transfer using complex optical fields: a review and perspective (Invited Paper)

“…The complex amplitude modulation, has been not only widely used in long-haul optical fiber communications [17] , but applied to metro/access and data center applications [18,19] . Moreover, chip-scale optical interconnects have also employed complex amplitude modulation for data information transfer [20][21][22] .…”