This article discusses the basic system architecture for terahertz (THz) wireless links with bandwidths of more than 50 GHz into optical networks. New design principles and breakthrough technologies

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In this paper we present four-wave mixing (FWM) based parametric conversion experiments in p-i-n diode assisted silicon-on-insulator (SOI) nano-rib waveguides using continuous-wave (CW) light around 1550 nm wavelength. Using a reverse biased p-i-n waveguide diode we observe an increase of the wavelength conversion efficiency of more than 4.5 dB compared to low loss nano-rib waveguides without p-i-n junction, achieving a peak efficiency of -1 dB. Conversion efficiency improves also by more than 7 dB compared to previously reported experiments deploying 1.5 µm SOI waveguides with p-i-n structure. To the best of our knowledge, the observed peak conversion efficiency of -1dB is the highest CW efficiency in SOI reported so far.

The phase dynamics that occur in bulk InGaAsP-InP semiconductor optical amplifiers (SOAs) in response to picosecond pulse excitations at 10 and 40 GHz are studied experimentally and numerically for various amplifier lengths. The time dependencies of the phase changes and of the absolute gain of the amplifier are measured simultaneously. The total phase shifts induced by 1.5-ps pulses at 10 GHz are higher than /spl pi/ in SOAs with active region lengths between 0.5 and 2 mm and exceed 2/spl pi/ in a 1.5-mm-long amplifier. Phase shifts above /spl pi/ are measured at 40 GHz in 1.5- and 2-mm-long SOAs. The dependence of the total phase shift on the amplifier bias current and length and on pump pulse energy is investigated. Numerical simulations based on a comprehensive time-domain SOA model allow us to confirm the experimental results for a wide range of amplifier parameters. In particular, SOAs with lengths up to 5 mm have been modeled, and the calculations suggest that the maximum phase shifts occur in amplifiers of approximately 2-mm length. The phase dynamics measurements are illustrated at the example of an optical time division multiplexing add-drop multiplexer, based on a SLALOM switch, gated by 10- or 40-GHz control pulses. We find that simultaneous good dropping and clearing is possible if the length and the operating conditions of the SOA in the switch are chosen such as to induce a full /spl pi/ phase shift

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International audienceWe present experimental and numerical investigations of Kerr nonlinearity compensation in a 400-km standard single-mode fiber link with distributed Raman amplification with backward pumping. A dual-pump polarization-independent fiber-based optical parametric amplifier is used for mid-link spectral inversion of 5 × 28-GBd polarization-multiplexed 16-QAM signals. Signal quality factor (Q-factor) improvements of 1.1 dB and 0.8 dB were obtained in the cases of a single-channel and a five-channel wavelength-division multiplexing (WDM) system, respectively. The experimental results are compared to numerical simulations with good agreement. It is also shown with simulations that a maximum transmission reach of 2400 km enabled by the optical phase conjugator is possible for the WDM signal

Abstract-The 2-µm wave band is emerging as a potential new window for optical telecommunications with several distinct advantages over the traditional 1.55µm region. First of all, the Hollow-Core Photonic Band Gap Fiber (HC-PBGF) is an emerging transmission fiber candidate with ultra-low nonlinearity and lowest latency (0.3% slower than light propagating in vacuum) that has its minimum loss within the 2-µm wavelength band. Secondly, the Thulium-doped fiber amplifier that operates in this spectral region provides significantly more bandwidth than the Erbium-doped fiber amplifier. In this paper we demonstrate a single-channel 2-µm transmitter capable of delivering >52 Gbit/s data signals, which is twice the capacity previously-demonstrated. To achieve this we employ discrete multi-tone (DMT) modulation via direct current modulation of a Fabry-Perot semiconductor laser. The 4.4-GHz modulation bandwidth of the laser is enhanced by optical injection locking, providing up to 11 GHz modulation bandwidth. Transmission over 500-m and 3.8-km samples of HC-PBGF is demonstrated.

Abstract-We experimentally investigate Kerr nonlinearity mitigation of a 28-GBd polarization-multiplexed 16-QAM signal in a 5-channel 50-GHz spaced wavelength-division multiplexing (WDM) system. Optical phase conjugation (OPC) employing the mid-link spectral inversion technique is implemented by using a dual-pump polarization-independent fiber-optic parametric amplifier (FOPA) and compared to digital backpropagation (DBP) compensation over up to 800-km in a dispersion-managed link. In the single-channel case, the use of the DBP algorithm outperformed the OPC with a Q-factor improvement of 0.9 dB after 800-km transmission. However, signal transmission was not possible with DBP in the WDM scenario over the same link length while it was enabled by the OPC with a maximum Q-factor of 8.6 dB.Index Terms-Coherent detection, fiber nonlinearity, optical phase conjugation (OPC), quadrature amplitude modulation (QAM), wavelength-division multiplexing (WDM), digital backpropagation (DBP), optical fiber communication.