Relation Between TDEC, Extinction Ratio and Chromatic Dispersion in 50G PON

We evaluate TDEC in a 50G-PON downstream through experiments and show the relation with receiver sensitivity at different fiber lengths and ER. The results show that TDEC effectively follows the penalty induced by transmission impairments

Real-Time 100Gb/s Downstream PAM4 PON Link with 34 dB Power Budget

We experimentally demonstrate in real-time a 34dB PON power budget, exceeding E1 ODN class, with 100Gb/s PAM4 modulation using an amplified O-Band EML plus receiver-side optical amplification and only low complexity FFE equalization

Enhanced Electrical Duobinary Decoder with Low-{BW} Based Receivers for Short Reach Indoor Optical Links

We propose and experimentally validate a novel scheme combining both binary and electrical duobinary detection. At 50Gb/s, in a 1-bit memory channel, we obtain a Rx sensitivity of -25.7dBm with a 25G-class Rx and a low path penalty after 20km using a 1342nm EML Tx

25Gb/s PAM4 adaptive receiver equalisation requirements for burst-mode transmission systems

Requirements for burst-mode equalisation in a 25Gb/s PAM4 system for passive optical network upstream traffic are analysed for different linear equaliser solutions, with transmission over 40km of fibre. The impact of chromatic dispersion, transmitter bandwidth restriction and non-linearities is considered

Chirp control in directly modulated 25G PAM4 transmitters for optical access networks

Narrowband filtering chirp control is demonstrated for a 25Gb/s PAM4 signal in directly modulated transmitters for next generation optical access systems, allowing 50km transmission without chromatic dispersion compensation with blue-shift filtering offering the best performance

Iterative block decision feedback equalization for IM/DD-based OCDM to compensate chromatic-dispersion-induced power fading

Orthogonal chirp-division multiplexing (OCDM) has recently been proposed as an attractive modulation technique for high-speed fiber-optic systems in virtue of its resilience against system impairments. In this paper, we propose an iterative block (IB) decision feedback equalization (DFE) algorithm for the intensity-modulation and direct-detection (IM/DD) based OCDM system to effectively mitigate the chromatic-dispersion (CD)-induced power fading in the fiber. An efficient algorithm is derived to simplify the IB-DFE at the receiver. Analysis is pro-vided to show that the fading effect is compensated by recovering the noisy signals in the vicinity of frequency notches. Simulations were carried out to study the performance of the proposed system. The results show that the proposed system with IB-DFE is able to compensate severe fading effects and improves the bit-error rate (BER) by several orders of magnitude. An experiment was implemented to realize 30.3-Gbit/s IM/DD-OCDM signal over 50-km fiber, in which power fading due to CD over 20 dB was observed. The experiment results show that the proposed system further reduced the required OSNR by 8 dB to achieve a BER of 3×10 −5

Orthogonal chirp-division multiplexing for IM/DD-based short-reach systems

Orthogonal chirp-division multiplexing (OCDM) has been recently proposed as an attractive modulation technique for realizing high-speed coherent lightwave systems in virtue of its resilience against system impairments. However, the complex-valued OCDM signal is not directly viable for optical intensity modulation and direct detection (IM/DD) systems. In this paper, a double-sideband (DSB)-modulated OCDM scheme is proposed for short-reach, high-speed IM/DD systems. In the proposed scheme, the real-valued OCDM signal is generated by a simple digital up-conversion technique, which converts the complex-baseband signal to a passband to avoid the aliasing for DSB modulation. At the receiver, inverse operations revert the signal back to the baseband for demodulation. Experiments were carried out to validate the feasibility and advantages of the proposed scheme, and OCDM signals with data rates up to 174.5 Gbit/s were successfully demonstrated. The results confirm that the proposed IM/DD-OCDM system is more robust to impairments and thus achieves better performance than a discrete multi-tone system

FDMA Point-to-Multi-Point Fibre Access System for Latency Sensitive Applications

We present a demo for a multiple uplink access system with real-time services. Several terminals transmit and are detected simultaneously through FDMA. The system can allow latency-sensitive and best-effort applications to share the network

Orthogonal chirp-division multiplexing for performance enhanced optical/millimeter-wave 5G/6G communications

Orthogonal chirp-division multiplexing is deployed as a novel waveform in an optical/millimeter-wave system. Enhanced channel estimation gives a 5-dB receiver sensitivity improvement over a conventional OFDM implementation, and compatibility with 256-QAM at 60-GHz is experimentally demonstrated

Point-to-point overlay of a 100Gb/s DP-QPSK channel in LR-PONs for urban and rural areas

The continuing growth in information demand from fixed and mobile end-users, coupled with the need to deliver this content in an economically viable manner, is driving new innovations in access networks. In particular, it is becoming increasingly important to find new ways to enable the coexistence of heterogeneous services types which may require different signal modulation formats over the same fiber infrastructure. For example, the same physical layer can potentially be used to deliver shared 10Gb/s services to residential customers, dedicated point-to-point (P2P) 100Gb/s services to business customers, and wireless fronthaul, in a highly cost-effective manner. In this converged scenario, the performance of phase modulated signals can be heavily affected by nonlinear crosstalk from co-propagating on-off-keying (OOK) channels. In this paper, the overlay of a 100G P2P dual-polarization quadrature phase-shift keying (DP-QPSK) channel in a long-reach passive optical network (LR-PON) in the presence of co-propagating 10Gb/s OOK neighboring channels is studied for two different PON topologies. The first LR-PON topology is particularly suited for densely populated areas while the second is aimed at rural, sparsely populated areas. The experimental results indicate that with an emulated load of 40 channels the urban architecture can support up to 100km span and 512 users, while the rural architecture can support up to 120km span and 1024 users. Finally, a system model is developed to predict the system performance and system margins for configurations different from the experimental setups and to carry out design optimization that could in principle lead to even more efficient and robust schemes