K. L. Yu

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.

Monolithic integration of a very low threshold GaInAsP laser and metal‐insulator‐semiconductor field‐effect transistor on semi‐insulating InP

Monolithic integration of 1.3‐μm groove lasers and metal‐insulator‐semiconductor field‐effect transistors (MISFET) is achieved by a simple single liquid phase epitaxy (LPE) growth process. Laser thresholds as low as 14 mA for 300‐μm cavity length are obtained. MIS depletion mode FET’s with n channels on LPE grown InP layer show typical transconductance of 5–10 mmho. Laser modulation by the FET current is demonstrated at up to twice the threshold current.

Carrier leakage and temperature dependence of InGaAsP lasers

A direct measurement of electron and hole leakage in InGaAsP/InP lasers has been carried out. The effect of electron leakage on the temperature sensitivity of InGaAsP/InP lasers has been revealed.

Recent developments in monolithic integration of InGaAsP/InP optoelectronic devices

Monolithically integrated optoelectronic circuits combine optical devices such as light sources (injection lasers and light emitting diodes) and optical detectors with solid-state semiconductor devices such as field effect transistors, bipolar transistors, and others on a single semiconductor crystal. Here we review some of the integrated circuits that have been realized and discuss the laser structures suited for integration with emphasis on the InGaAsP/InP material system. Some results of high frequency modulation and performance of integrated devices are discussed.

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.