Kota Asaka

Physical layer aspects of NG-PON2 standards–Part 2: System design and technology feasibility [Invited]

This is the second of a two-part paper intended to provide technical insight and rationales behind the recently approved ITU-T G.989.2 Recommendation: the physical media dependent layer specification of the 40-gigabit-capable passive optical networks (NG-PON2). While Part 1 of the paper discusses topics related to the optical link design, Part 2 focuses on wavelength control, technology feasibility, management and control channel design, and potential future standardization directions of such a multi-wavelength PON system. As the NG-PON2 system will continue to evolve, technology extensions are also discussed to provide guidance for future research.

Energy efficient IM-DD OFDM-PON using dynamic SNR management and adaptive modulation

This paper describes the demonstration of an energy efficient orthogonal frequency division multiplexing passive optical network using the dynamic signal to noise ratio (SNR) management and adaptive modulation. Controlling the calculation precision and modulation format minimizes the energy consumption of digital signal processor while satisfying the requirements of bit error ratio. We show that the calculation precision and modulation format can be optimized according to the optical received power, and realize a 58.7% effective energy efficiency per bit in an FPGA-based receiver experimentally.

40-km reach symmetric 40-Gbit/s λ-tunable WDM/TDM-PON using synchronized gain-clamping SOA

We propose a high power λ-tunable burst-mode transmitter with an output of over +10 dBm using a synchronized gain-clamping booster SOA, and demonstrate a 40-dB loss budget and 40-km reach symmetric 40-Gbit/s λ-tunable WDM/TDM-PON.

Field Trial of Long-Reach and High-Splitting λ-Tunable TWDM-PON

This paper presents the worlds first field trial of a 40-km reach and over 512-split symmetric-rate 40-Gbit/s λ-tunable time and wavelength division multiplexing passive optical network (TWDM-PON) that utilizes our newly developed high-speed λ-tunable optical network unit transceivers and automatic gain controlled semiconductor optical amplifier-based PON extender for repeater and central office use. The upstream signals for C-band and downstream signals for L+-band in our developed λ-tunable TWDM-PON comply with the wavelength plan of ITU-T G.989 series. In a field trial, we successfully demonstrate error free λ-tunable transmission for the 40-km reach and 1024-split (maximum number) symmetric-rate 40-Gbit/s λ-tunable TWDM-PON over installed standard single-mode fiber links, and advanced network functions such as dynamic load balancing, incremental system upgrade, optical subscriber unit protection, and OLT equipment power saving are also confirmed.

What will be killer devices and components for NG-PON2?

Possible device configurations for the next-generation passive optical network (NG-PON2) are reviewed on the basis of system requirements. The most significant issue is how to cost-effectively implement a tunable function in optical components because NG-PON2 introduces a wavelength division multiplexing.

Long-reach ¿-tunable WDM/TDM-PON using synchronized gain-clamping SOA technology [invited]

This paper proposes a 40 Gbit/s class λ-tunable wavelength division multiplexing and time division multiplexing passive optical network (WDM/TDM-PON) system that uses our newly developed high-output-power λ-selective burst-mode transmitter (B-Tx) in an ONU and a 4 × 4 cyclic arrayed waveguide grating as a photonic router. Our developed B-Tx utilizes a booster semiconductor optical amplifier that employs a pattern effect suppression technique incorporating synchronized gain-clamping light injection, and it obtains a high output power of over +10 dBm without signal waveform distortion at all wavelength channels. We demonstrate a 40 Gbit/s λ-tunable WDM/TDM-PON that achieves a 40 km transmission reach and a 40 dB loss budget.

High output power and burst extinction ratio λ-tunable ONU transmitter using burst-mode booster SOA for WDM/TDM-PON

This paper proposes a high output power and high burst extinction ratio wavelength (λ)-tunable optical network unit (ONU) transmitter for long-reach and high-splitting ratio wavelength-division multiplexing and time-division multiplexing passive optical network (WDM/TDM-PON) systems. Our λ-tunable ONU burst-mode transmitter (B-Tx) utilizes a simply configured burst-mode controlled booster semiconductor optical amplifier (SOA) that employs the pattern effect mitigation technique of gain peak detuning. A high output power and burst extinction ratio are successfully achieved at all upstream wavelength channels, over +10.0 dBm and 66.0 dB, respectively. This burst extinction ratio performance satisfies the ONU requirement for a 64-split WDM/TDM-PON with crosstalk penalty of better than under 0.1 dB. Moreover, the pattern effect is greatly mitigated and 40 km transmission penalty of under 0.8 dB is achieved. We successfully demonstrate over a 41 dB loss budget and 40 km reach λ-tunable WDM/TDM-PON without an optical-amplifier-based PON repeater.

High Output Power and Burst Extinction Ratio ONU Using a Simple Configuration Booster SOA with Gain Peak Detuning for WDM/TDM-PON

We propose a high-output power λ-selective transmitter utilizing a simple configuration burst-mode booster SOA with gain peak detuning that achieve pattern effect mitigation. We successfully demonstrate over 40-dB loss budget and 40-km reach WDM/TDM-PON.

High output power OLT/ONU transceivers for 40 Gbit/s symmetric-rate NG-PON2 systems

More than +6 dBm output power OLT/ONU transceivers which comply with the wavelength allocation plan of the next-generation passive optical network stange2 (NG-PON2) standard (ITU-T G.989.2) are successfully demonstrated thanks to a newly developed semiconductor optical amplifier (SOA) - integrated transmitter.

Novel Automatic Service Restoration Technique by Using Self-Reconfiguration of Network Resources for a Disaster-struck Metro-Access Network

This paper shows the concept of the elastic lambda aggregation network (EλAN) that will achieve an elastic common access infrastructure for the metro-access network. It proposes a service restoration technique that uses optical path switching and intercentral office handover for EλAN to recover from disasters. The feasibility of the proposed service restoration technique is successfully demonstrated for the first time by using a prototype testbed of a metro-access network. By applying both orthogonal frequency division multiplexing and adaptive modulation, the system automatically changes the transmission parameters (modulation level, the number of subcarriers, and symbol rate) according to the service requirements and conditions of the optical distribution network, such as the links end-to-end optical loss, in order to achieve accommodate multiple services. In the experiment, an optical network unit in a faulted system automatically reconnected within 10 s to another office 20-km away with the same throughput.