High-power operation of aluminum-free (κ=0.98 μm) pumplaser for erbium-doped fiber amplifier

The authors discuss the fabrication and characteristics of high-power (P_CW=430 mW) InGaAs/InGaAsP/InGaP ridge waveguide lasers emitting at λ=0.98 μm, which is the optimum wavelength for pumping erbium-doped fiber amplifiers. In the past, high-power operation of Al-free pump lasers has been limited to 150 mW because of catastrophic optical damage of the mirror facet. This problem has been largely removed by increasing the spot size of the laser with the aid of an improved waveguide design. As a result, Al-free lasers can now achieve a maximum power comparable to the conventional GaAlAs-based pump lasers for λ=0.98 μm     

High-performance 980-nm strained-layer GaInAs-GaInAsP-GaInP quantum-well lasers grown by all solid-source molecular-beam epitaxy

High-performance strained-layer GaInAs-GaInAsP-GaInP separate-confinement quantum-well lasers emitting at /spl lambda/=980 nm were grown by all solid-source molecular-beam epitaxy. Valved cracker cells were employed to generate group-V beam fluxes. Fabricated ridge-waveguide lasers exhibited stable, kink-free, single-mode operation up to 260 mW. A maximum output power of 550 mW was achieved. Complete thermal roll-over tests were done tens of times without any sign of degradation for p-side up-mounted lasers. Preliminary lifetime tests for over 4500 h at 150-mW power level indicate that these aluminum-free pump lasers are very reliable sources for pumping light into erbium-doped fiber amplifiers.     

Tensile-strained GaAsP/GaInAsP/GaInP quantum well lasers

Tensile-strained GaAsP/GaInAsP/GaInP separate-confinement-heterostructure single-quantum-well (SCH-SQW) lasers are reported for the first time. A low threshold current density of 261 A/cm² and a high characteristic temperature of 190 K were obtained for a 1600-μm long broad-area laser having ~0.3% lattice strain. The internal quantum efficiency was as high as 93% and internal waveguide loss 3.3 cm^-1. Some primary results of unstrained GaAs/GaInAsP and compressive-strained (1.4%) InGaAs/GaInAsP SCH-SQW lasers are also presented. Both the tensile and compressive-strained lasers exhibited higher quantum efficiency than the unstrained lasers. On the other hand, the tensile-strained lasers had nearly the same internal waveguide loss and threshold current as the unstrained lasers     

InGaAs/lnP heterojunction bipolar transistor grown by all-solidsource molecular beam epitaxy

State-of-the-art InGaAs/InP heterojunction bipolar transistors were grown by all-solid source molecular beam epitaxy. Fabricated transistors showed cutoff frequencies of >100 GHz with an emitter area of 1.5×5 μm². Together with recent studies. These results demonstrate that the valved cracker technique is a very competitive nontoxic growth method     

High-gain, high-speed InP/InGaAs double-heterojunction bipolartransistors with a step-graded base-collector heterojunction

We show that by using InP for the emitter and collector layers, and a thin high-doped base layer, it is possible to achieve both a high DC current gain and a high maximum frequency of oscillation. We have fabricated InP/InGaAs double heterojunction bipolar transistors (DHBT's) with cutoff frequencies f_T and f_max of 92 and 95 GHz, respectively, with a DC current gain of over 100. The maximum cutoff frequencies were 107 and 104 GHz     

A Ga0.51In0.49P/GaAs-based photovoltaic converter for two-directional optical power and data transmission

A GaAs-based photovoltaic converter for optical-to-electrical power conversion and for data transmission was developed. the device structure is based on a modified GaAs solar cell structure having a lattice-matched Ga_0.51In_0.49P window layer. the converter consists of an array of series-connected photovoltaic cells. the input optical laser power is transmitted via a single optical multimode fibre and distributed homogeneously to the separate cells. One of the cells has separate connections for acting as a light-emitting diode for data transmission in the opposite direction. the conversion eficiency of the individual cells was measured to be 49%, and the array conversion efficiency was 41%.