Toshiharu Miyahara

NRZ-OOK-to-RZ-BPSK modulation-format conversion using SOA-MZI wavelength converter

A novel all-optical modulation-format conversion from nonreturn-to-zero on-off keying (NRZ-OOK) to return-to-zero binary phase-shift keying (RZ-BPSK) is proposed. A Mach-Zehnder interferometric (MZI) wavelength converter consisting of integrated semiconductor optical amplifiers (SOAs) is utilized to implement the proposed format conversion. Error-free operation at a bit rate of 10.7 Gb/s is experimentally demonstrated in order to show the feasibility of the proposed scheme. The received sensitivity of the converted signal is improved by 2.9 dB compared with a back-to-back NRZ-OOK signal at BER=10 -9. In addition, a reasonable dispersion tolerance of the converted signal up to plusmn500 ps/nm is observed. The numerical simulation based upon the carrier-rate equation verifies the experimental results

Polarization-Insensitive Monolithic 40-Gbps SOA–MZI Wavelength Converter With Narrow Active Waveguides

A polarization-insensitive monolithic 40-Gbps semiconductor optical amplifier (SOA)-Mach-Zehnder interferometer wavelength converter has been developed. Based on the photon-electron rate equation, we optimized the dimensions of the waveguide structure to maximize the field confinement in the active layer. An InGaAsP active layer with narrow SOA waveguide effectively enables polarization-insensitive high-speed wavelength conversion. High-precision wafer processing technique enabled the fabrication of submicrometer-wide active waveguides with low current leakage. Input waveguide arrays were fabricated at intervals of 25 mum and mounted in a module with two-lens aspherical lens optics. The 40-Gbps nonreturn-to-zero wavelength conversion experiment demonstrates a clear eye opening over full C-band operation

All-optical switching of 40 Gb/s packets by MMI-BLD optical label memory

We demonstrated all-optical label storing and switching for 40 Gb/s optical packets by using all-optical signal processing of multimode interference bistable laser diode optical flip-flops. The stored optical labels in the optical flip-flop controlled an all-optical switch to forward the injected optical packets. The 40 Gb/s optical packets were successfully switched in the all-optical scheme with 11-dB extinction ratio. Error-free operation for the output packets from the switch was also obtained with 1.3-dB power penalty. The presented all-optical packet switching has the advantages of ultrafast switching and transparency of data rate and format, suitable for the future optical networks.

Polarization-Insensitive SOA-MZI Monolithic All-Optical Wavelength Converter for Full C-band 40Gbps-NRZ Operation

Bulk InGaAsP SOA-MZI monolithic wavelength converter has been optimized for fast gain recovery and clear eye openings at 40Gbps-NRZ format. Full C-band operation and polarization-insensitive operation were achieved at 40Gbps-NRZ.

Label-based path switching and error-free forwarding in a prototype optical burst switching node using a fast 4/spl times/4 optical switch and shared wavelength conversion

We demonstrate for the first time optical burst switching using fast and scalable EO switch and a shared wavelength converter for contention resolution. 3.5 /spl mu/m label routing of variable-length bursts and error-free operation was achieved at 10 Gbps payload.

Optical Burst Switching Router With 40-,10-Gb/s Bit-Rate Transparent Contention Resolution

We report a bit-rate transparent optical burst switching (OBS) router prototype using a fast 5 times 5 PLZT [(Pb,La)(Zr,Ti)O3 ] optical matrix switch. Dynamic switching in a two-wavelength, 2 times 2 OBS switch is demonstrated. Contention resolution using a tunable Mach-Zehnder interferometer wavelength converter for both 40- and 10-Gb/s bursts is demonstrated for the first time. Error-free operation was achieved for both bit rates under the same settings, as required in autonomous networks

All-optical format conversion from NRZ-OOK to RZ-BPSK using SOA-MZI wavelength converter

We propose a novel all-optical NRZ-OOK/RZ-BPSK format conversion scheme, using cross-phase modulation effects in a MZI-SOA. We experimentally demonstrate error free conversion at 10.7 Gb/s with a negative power penalty of 2.9 dB

MMI-BLD optical flip-flop for all-optical packet switching

We have demonstrated all-optical packet switching, in which an MMI-BLD optical flip-flop worked as a label memory. The optical flip-flop allowed self-routing of multiple-wavelength packets with 338-ps switching time and 14-dB on-off ratio.

Input-Power and Polarization Insensitive All-Optical Wavelength Converter With Monolithically Integrated Monitor PD and Gain-Controlled SOA

This paper presents a polarization-insensitive semiconductor optical amplifier Mach-Zehnder Interferometer (SOA-MZI) wavelength converter with a wide dynamic range. Direct detection of the wavelength-converted output signal power and feedback control of the signal power input to the SOA-MZI are proposed and are confirmed to be able to reduce the variation with input signal power and polarization. The gain-controlled SOA (GC-SOA) and monitor PD used to implement the feedback control are monolithically integrated into the SOA-MZI wavelength converter. A dynamic range of over 8 dB is obtained for TE and TM polarized input signals NRZ modulated at 43 Gb/s under feedback control, 7 dB better than with no feedback.

Multi-hop Transmission with Wavelength Conversion for Collision Resolution in PLZT Matrix Switch-based Optical Burst Switching Node Prototype

Multi-hop cascadibility of a PLZT matrix switch-based optical burst switching node prototype is presented. Using a 50 km recirculating loop setup and a 4times4 matrix switch, more than 10 hop transparency at 10 Gb/s was achieved. Hop-by-hop wavelength conversion for contention resolution and signal reshaping effect was confirmed.