Masahiro Sarashina

First Demonstration of Coexistence of Standard Gigabit TDM-PON and Code Division Multiplexed PON Architectures Toward Next Generation Access Network

World-first coexistence trial of TDM and CDM giga-bit passive optical networks (PONs) was successfully completed. A very shallow minimum isolation of 7 dB between G- and CDM-PON at OLT and ONU in the ITU-T G.984.5 enhancement band was demonstrated. The feasibility of bidirectional transmission on the same wavelength was confirmed. The backscattering optical noise does not seriously affect the maximum reach of CDM-PON. Adding the CDM-PON onto GPON can provide following technical and economical impacts: low-cost coexistence, minimum service outage, and combination of best-effort and guaranteed-bandwidth for efficient and high-quality network services due to CDM feature.

First system demonstration of hitless λ-tuning sequence for dynamic wavelength allocation in WDM/TDM-PON

We propose hitless wavelength-tuning sequence for dynamic wavelength allocation in WDM/TDM-PONs and demonstrate highly frequent wavelength-tunings in 100-ms intervals without data-frame loss using MAC boards. Pay-as-you-grow operation based on the proposed sequence is also shown.

Demonstration of Load-Balancing Operation Based on Hitless Dynamic Wavelength Allocation on Symmetric 40-Gbit/s λ-Tunable WDM/TDM-PON

This paper reports the world-first system-level demonstration of dynamic wavelength allocation (DWA) on a wavelength-tunable (λ-tunable) wavelength division multiplexing/time division multiplexing-passive optical network (WDM/TDM-PON). To achieve DWA, a DWA calculation is necessary that determines new optical network unit assignments to the optical line terminal ports according to the bandwidth demand. In addition, a wavelength-tuning (λ-tuning) sequence that induces no data-frame loss, i.e., a hitless λ-tuning sequence, is essential. First, we propose a bidirectional hitless λ-tuning sequence and investigate its feasibility using media access control boards that we developed for symmetric 40-Gbit/s λ-tunable WDM/TDM-PONs, which are also the worlds first. Then, with a DWA calculation according to the downstream traffic loads, we show automatic dynamic load-balancing operation.

Demonstration of 1.25 Gb/s

In this letter, 1.25 Gb/s × 8-channels simultaneous multiplexing using 8-chip electrical codes is experimentally demonstrated for the downlink of a 10-Gb/s electrically code-division-multiplexing passive optical network (ECDM-PON) system. For electrical encoding and decoding, 10-Gb/s multilevel signal generation and 10 Gchip/s correlator as a decoder are utilized. We demonstrate 10-Gb/s ECDM error-free optical transmission over 20 km of single-mode fiber.

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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.

8-Channels ECDM Using Eight-Chip Electrical Coding

We proposed and demonstrated 40Gbps, 256-label optical packet switching employing a clockless serial optical code label processing. Eight different SSFBGs label recognizers with high auto- to cross-correlation peak ratio were used for optical label correlation.

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

This paper clarifies the scalability of the hitless wavelength-tuning (λ-tuning) sequence for dynamic wavelength allocation (DWA) on a λ-tunable wavelength-division-multiplexing/time-division-multiplexing passive optical network (WDM/TDM-PON). The λ-tuning that induces no data-frame loss, i.e., hitless λ-tuning, is essential in DWA. We derive requirements to prevent two types of upstream data-frame loss that the λ-tuning causes. To clarify the scalability of the hitless λ-tuning sequence against system parameters, we theoretically analyze the maximum input data rate to the optical network units (ONUs) to achieve λ-tuning without upstream data-frame loss while varying values for buffer size and λ-tuning time of the transceivers in ONUs and the DWA cycle. Then, using media access control boards that we developed for symmetric 40 Gbit/s λ-tunable WDM/TDM-PONs, we demonstrate hitless λ-tuning and confirm the validity of the theoretical analysis.

First Demonstration of Clockless Serial Optical Code Label Switching with SSFBGs Label Recognizer

First demonstration of asymmetric PON system (10 Gbps × 16 ch downstream) using OTDM and OCDM technologies is presented. We accomplished a transmission over 20 km SMF with optimized dispersion tolerance.

Scalability of a hitless λ-tuning sequence to upstream transmission at dynamic wavelength allocation in WDM/TDM-PON [invited]

For the first time, we experimentally demonstrated asynchronous ultrahigh speed optical label switching using 4 SSFBGs label recognizers with the guard time of 3 ns. We also confirmed that the optical label recognizer/processor can operate for optical label after 40 km of SMF transmission without dispersion compensation

A Study of 160Gbps PON System Using OTDM and OCDM Technologies

First time, we have experimentally demonstrated 1.25-Gbps/subscriber 10-Gchip/s ECDM-PON upstream transmission over 20-km SSMF using WDM light sources. Additionally, optical beating induced performance degradation was investigated by varying WDM channel spacing from 100-GHz to 10-GHz.