Masahiro Yuda

Improvement of kink-free output power by using highly resistive regions in both sides of the ridge stripe for 980-nm laser diodes

Suppressing the lateral expansion of driving current by forming highly resistive regions at both sides of the ridge stripe in ridge-waveguide-type 980-nm laser diodes leads to an enhanced kink-free output power. The highly resistive regions are formed by hydrogen passivation of p-type carrier (Zn) on the plasma exposure in a mixture gas of methane and hydrogen. A simulation predicted a decrease in local gain in the lateral direction at both sides of the ridge stripe. Fabricated laser diodes with the highly resistive regions exhibit kink-free output power of over 500 mW, showing an increase in kink-free power of 85 mW on average with an increase of slope efficiency of about 10% compared to those without highly resistive regions.

High-power highly reliable 1.02-1.06-/spl mu/m InGaAs strained-quantum-well laser diodes

By growing the InGaAs active layer at temperatures lower than in conventional growth, we extended the lasing wavelength and presented the high reliability in InGaAs strained-quantum-well laser diodes. Equivalent I-L characteristics were obtained for 1.02-, 1.05-, and 1.06-/spl mu/m laser diodes with a cavity length of 1200 /spl mu/m. Maximum output power as high as 800 mW and fundamental transverse mode operation at up to 400 mW were obtained at 1.06 /spl mu/m and an 1800-/spl mu/m cavity. Stable operation was observed for over 14 000 h under auto-power-control of 225 mW at 50/spl deg/C for the 1.02-, 1.05-, and 1.06-/spl mu/m lasers with a 900-/spl mu/m cavity.

High-Temperature Operation of 1.26-

In this paper, we have newly developed an InGaAs metamorphic buffer on a GaAs substrate grown by metal-organic vapor-phase epitaxy, and realized a fully relaxed quasi-InGaAs substrate with low threading dislocation density. We have also successfully developed a 1.3-mu m-range ridge waveguide laser with InGaP upper cladding and InAlGaAs lower cladding layers. This laser has achieved the highest continuous-wave operating temperature (173degC) reported for a metamorphic laser. We measured the relaxation oscillation frequency from the relative intensity noise and undertook a 10-Gb/s direct modulation experiment.

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We have developed high-performance 1.3-mum-band laser diodes on an InGaAs ternary substrate with a low indium content (In:0.1) grown by a novel bulk crystal growth technique called the traveling liquidus-zone (TLZ) method. This laser has a long-wavelength lasing of 1.28 mum and provides lasing operation up to 195degC by using a highly strained InGaAs quantum well. The characteristic temperatures are 130 K from 25 to 95degC and 95 K from 95 to 155degC. We investigated junction heating by comparing the lasing wavelengths for pulsed and continuous-wave (CW) operation. And, we showed the possibility of realizing a high-performance laser on an InGaAs ternary substrate.

m Ridge Waveguide Laser With InGaAs Metamorphic Buffer on GaAs Substrate

Ruthenium(Ru)-doped InP-buried electro-absorption optical modulators are demonstrated for the first time. Ru-doped InP-burying semi-insulating layers were grown by conventional metal-organic vapor phase epitaxial growth (MOVPE) with phosphin. Semi-insulating layers with high resistivities of 108–109 Ωcm were obtained easily and reproducibly. The capacitance and the leakage current of the modulators were reduced significantly because the interdiffusion between the transition metal and zinc decreased.

High-Characteristic-Temperature 1.3-

We have realized a high-performance ridge waveguide laser diode on an InGaAs ternary substrate. To improve the thermal conductivity, we chose a low indium content (In: 0.13) InGaAs substrate and realized a 1.31-µm emission using highly strained InGaAs multiple-quantum-wells. The improved thermal conductivity of the substrate enables continuous wave operation even with a reduced ridge width and a short cavity length (L = 200 µm). These improvements led to the first demonstration of a 10-Gbps data transmission using a laser on an InGaAs ternary substrate.

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We have successfully developed a 1.26 mum ridge waveguide laser diode with an InGaAs metamorphic buffer on an GaAs substrate grown by metal-organic vapor-phase epitaxy. This laser has achieved the highest operating temperature (188degC) reported for a metamorphic laser.

m-Band Laser on an InGaAs Ternary Substrate Grown by the Traveling Liquidus-Zone Method

We have realized 10-Gb/s direct modulation up to 100degC using a metamorphic InGaAs multiple-qunatum well (MQW) laser on a GaAs substrate. The highly strained InGaAs quantum well (QW) and strain-compensated GaAs barrier layer allowed 1.3-mum-range lasing and an increased number of QWs (six). This laser with a 200-mum-long short cavity and a narrow ridge had maximum relaxation oscillation frequencies of 13 and 6 GHz at 25degC and 100degC, respectively. A 10-km single-mode fiber error-free transmission was successfully obtained at a temperature of 85degC .

Ruthenium-Doped Semi-Insulating InP-Buried InGaAlAs/InAlAs Multi-Quantum-Well Modulators

We have developed high performance ridge waveguide laser diodes on an InGaAs ternary substrate grown by a novel bulk crystal growth technique (TLZ method). A low indium content (In: 0.13) InGaAs substrate improves the thermal conductivity and enables laser operation even with a short cavity (L=200 mum). Single lateral mode operation was obtained by reducing the ridge width. This laser operates at a long wavelength of 1.31 mum with a highly strained InGaAs quantum well. These improvements led to the first demonstration of a 10 Gbps data transmission using a ridge waveguide laser on an InGaAs substrate.

10-Gbps Direct Modulation Using a 1.31-µm Ridge Waveguide Laser on an InGaAs Ternary Substrate

We have developed high-performance 1.3 mum-band laser diodes on an InGaAs ternary substrate with a low indium content (In: 0.1) grown by a novel bulk crystal growth technique (TLZ method). This laser operates at a long wavelength of 1.28 mum and at temperatures up to 195degC by using a highly strained InGaAs quantum well. The characteristic temperatures are 130 K from 25 to 95degC and 95 K from 95 to 155degC