A. Hasson

Direct measurement of the carrier leakage in an InGaAsP/InP laser

Carrier leakage over the heterobarrier in an InGaAsP/InP laser is measured directly in a laser-bipolar-transistor structure. Experimental results indicate a significant amount of carrier leakage under normal laser operating conditions.

Study and application of the mass transport phenomenon in InP

A study of the mass transport phenomenon in InP is presented. Conditions and possible explanation for the transport process are discussed. Characteristics of the mass transported InP homojunctions are described and compared with those in the InP–InGaAsP heterojunctions. Effects of the mass transported junction on laser performance are discussed.

Field and hot carrier enhanced leakage in InGaAsP/InP heterojunctions

A model calculation for the field and hot carrier enhanced electron leakage in InGaAsP/InP LEDs and lasers is presented. The significant influence of the doping level in the P-InP confining layer on leakage current is confirmed.

Low threshold InGaAsP terrace mass transport laser on semi‐insulating substrate

Very low threshold InGaAsP terrace lasers on semi‐insulating (SI) InP substrate have been fabricated using the mass transport technique. The fabrication process involves a single‐step liquid phase epitaxial (LPE) growth followed by a mass transport of InP at ∼675 °C in the presence of an InP cover wafer. Lasers operating in the fundamental transverse mode with smooth far‐field patterns and threshold currents as low as 9.5 mA have been obtained.

InGaAsP/InP undercut mesa laser with planar polyimide passivation

An undercut mesa laser is fabricated on an n + -InP substrate using a single step liquid phase epitaxy growth process and a planar structure is obtained by using a polyimide filling layer. The lasers operate at fundamental transverse mode due to a scattering loss mechanism. Threshold currents of 18 mA and stable single transverse mode operating at high currents are obtained.

Phase‐locked InGaAsP laser array with diffraction coupling

A phase‐locked array of InGaAsP lasers has been fabricated for the first time. This 50‐μm‐wide array utilized diffraction coupling between adjacent lasers to achieve phase locking. Threshold current as low as 200 mA is obtained for arrays with 250‐μm cavity length. Smooth single‐lobe far‐field patterns with beam divergence as narrow as 3° have been achieved.

Low threshold InGaAsP/InP lasers with microcleaved mirrors suitable for monolithic integration

Low threshold InGaAsP/InP injection lasers on semi‐insulating InP substrates have been developed with mirrors fabricated by the microcleavage technique. Miniature suspended bridges containing the laser channels have been formed and then microcleavage has been accomplished by the use of ultrasonic vibrations. Lasers with current thresholds as low as 18 mA with 140‐μm cavity length and with 35–45% differential quantum efficiency have been obtained.

Short cavity InGaAsP/InP lasers with dielectric mirrors

Short cavity length (38 µm) lasers have been fabricated using a recently developed microcleavage technique. SiO2-amorphous Si multilayer coatings have been evaported on the lasers to obtain high reflectivity mirrors. The lasers have current thresholds as low as 3.8 mA with 85% reflecting front mirror and high reflectivity rear mirror and 2.9 mA with two high reflectivity mirrors. Single longitudinal mode operation is observed over a wide range of driving currents and temperatures.

Selective low-temperature mass transport in InGaAsP/InP lasers

A low-temperature mass transport process in InP was investigated. Mass transport of InP was achieved at 570–600 °C in a closed ampoule using iodine or InI as a catalytic transporting agent. Accomplishing the mass transport process at lower temperature has eliminated the problem of thermal etching and resulted in lasers with higher T0.

High‐power, single‐mode operation of an InGaAsP/InP laser with a grooved transverse junction using gain stabilization

The high-power performance of a groove InGaAsP/InP transverse junction laser fabricated on a semi-insulating InP substrate has been investigated. Peak power of over 250 mW/facet for pulsed operation and 11 mW/facet cw are achieved with stable fundamental mode operation and narrow beam width. It is suggested that the single-mode operation is caused by a gain stabilizing mechanism related to the transverse junction injection profiles.