Y. Shibata - IEEE Xplore Author Profile

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We demonstrate 40-Gbit/s operation by chirp control and increased output power employing an EADFB laser integrated with short-cavity SOA. We achieved 5-km SMF transmission in the 1.55-μm wavelength with lower power consumption than a stand-alone EADFB.Show More
Recent results are reported for a 1.3-μm InGaAlAs directly modulated laser (DML) with a ridge waveguide structure. We realized a 3-dB-down electrical-to-optical (E/O) response of 34 GHz for a 150-μm DML. Clear eye openings were obtained at 43 Gb/s up to 60°C and at 50 Gb/s at 25°C.Show More
A MZ optical modulator (MZM) with a novel planar structure was proposed. A single-RF drive push-pull MZM with a simple coplanar waveguide (CPW) was fabricated by utilizing a (110)-oriented InP substrate in terms of the crystallographic orientation dependence of the electro-optic Pockels effect. The device exhibits a 3 dB-EO bandwidth of 30 GHz and 40 Gb/s NRZ high speed modulation.Show More
We demonstrate 50-Gb/s direct modulation by using 1.3-μm distributed-feedback lasers with a ridge waveguide structure. We employed InGaAlAs material for a multiple-quantum well to obtain a low damping factor K, and fabricated a ridge waveguide structure buried in benzocyclobutene to realize a structure with a low parasitic capacitance. In addition, to obtain high maximum frequency relaxation oscil...Show More
We present a traveling-wave-electrode InP-based Mach-Zehnder (MZ) modulator that employs an n-p-i-n waveguide structure. The structure provides low electrical and optical propagation losses, which enables the modulator to operate at a high baud rate with a low driving voltage and a low optical insertion loss. We developed a compact 40-Gb/s differential phase shift keying (DPSK) tunable wavelength ...Show More
We clarified the degradation modes of an InP-based semiconductor optical Mach-Zehnder modulator (MZM) using high-power light-injected accelerated aging tests. Degradation clearly occurred at the light injected side of the edge on the electric field applied region. We found that the degradation threshold depends strongly on temperature, wavelength and bias voltage. By correlating these parameters, ...Show More
The stability of the extinction characteristics of an InP-based Mach-Zehnder modulator is clarified in detail. The changes in the half-wavelength voltage (Vπ) and null point voltage (Vnull) are investigated under long-term high-temperature aging tests. The time correlations with the change in Vπ and Vnull are different from each other. By using a statistical treatment of the Weibull distribution, ...Show More
We fabricated an ultra-compact InP-based DP-QPSK modulator by the hybrid integration of an InP twin-IQ modulator and a PLC polarization multiplexing circuit for the first time. 112-Gb/s DP-QPSK modulation is successfully demonstrated.Show More
Compact InP Mach-Zehnder modulators with traveling-wave electrodes and an npin waveguide structure are developed for high-speed transmission systems. We successfully demonstrate 40Gbit/s DPSK, 112Gbit/s DP-QPSK and 50Gbit/s 16QAM signal generation using a single MZ modulator.Show More
A semiconductor Mach-Zehnder modulator was integrated with a tunable-wavelength laser by using monolithic and hybrid integration techniques. Tunable-wavelength 40-Gbit/s DPSK modulation and 10-Gbit/s NRZ modulation were successfully demonstrated for hybrid and monolithic devices, respectively.Show More
In this paper a tunable DFB laser array (TLA) with a long-cavity (1500 μm) DFB structure. The laser covers a 40-nm (4.8-THz) tuning range in the L-band with a fiber output power of 20 mW and a high SMSR of >;50 dB. Narrow linewidth operation below 160 kHz was obtained over the entire tuning range. An InP DQPSK modulator with low electrical and optical propagation losses is also developed. Moreover...Show More
A monolithically integrated tunable transmitter consisting of a tunable DFB laser array and a Mach-Zehnder modulator with a 2-channel SOA is demonstrated. The total output power is twice that of the conventional configuration.Show More
We have successfully demonstrated the 180-km transmission of 10-Gbit/s NRZ signal using a dual-modulated EA-DFB laser. Directly frequency modulated DFB laser having semi-insulated semiconductor buried heterostructure effectively suppresses thermal frequency modulation, resulting in error-free transmission with PRBS of 231-1.Show More
We have successfully demonstrated 112Gbit/s DP-QPSK modulation using a wavelength tunable pulse carver module, in which a wavelength tunable DFB laser array (TLA) and an InP n-p-i-n Mach-Zehnder modulator are co-packaged, and a dual-drive InP Mach-Zehnder IQ modulator module.Show More
A monolithically integrated tunable transmitter consisting of tunable DFB laser array and Mach-Zehnder modulator is developed. Power penalty in the chromatic dispersion range of ±800 ps/nm with zero-chirp operation is less than 0.7 dB, modulating at 10-Gbit/s NRZ signal.Show More
This paper describes the 10-Gb/s, full C-band (1530 to 1565 nm) operation of 1.55-m electroabsorption modulators (EAMs) designed to eliminate the cost of a back up light source for a 10-Gb/s dense wavelength division multiplexing (DWDM) system. We employ InGaAlAs as the material for the EAM multiple-quantum well (MQW), and design it to achieve a sufficient extinction ratio and a low chirp () param...Show More
We report a monolithically integrated 8×8 wavelength-routing switch with semiconductor-optical-amplifier-based wavelength converters and double-ring-resonator-coupled tunable lasers incorporated with highly reflective cavity mirrors. The dry-etched mirror coated with Au enables flexibility in device layout. It allows highly reflective mirrors in a chip and antireflective coating on both the input ...Show More
InP-based photonic integrated circuits are key devices for constructing photonic networks with low cost, low power consumption and small footprint. Many types of components are required to span various application areas, from backbone to on-chip.Show More
This paper reviews our recent studies of InP n-p-i-n Mach-Zehnder modulators monolithically integrated with a semiconductor optical amplifier. Lossless operation for the entire C-band and good dynamic performance are obtained.Show More
We demonstrate an all-optical wavelength-routing switch monolithically integrated with four wavelength converters and an 8times8 arrayed-waveguide-grating (AWG) filter. In the switch, double-ring-resonator-coupled tunable laser diodes allow rapid and stable switching between output ports (~5 ns) and optical gates based on a parallel amplifier structure prevent the input optical signal from being r...Show More
A 10-Gbit/s, 1.58-mu m, InGaAlAs electroabsorption modulator (EAM) integrated distributed-feedback (DFB) laser (EML) with a twin waveguide (TWG) structure is operated experimentally over a wide temperature range of 0 to 80degC. We introduce an InGaAlAs multi-quantum well (MQW) system for both LD and EAM MQWs, because this material has temperature-tolerant characteristics. These layers are grown us...Show More