K. Brown-Goebeler

Temperature dependence of GaAs‐AlGaAs vertical cavity surface emitting lasers

The temperature performance of GaAs‐AlGaAs vertical cavity surface emitting lasers has been studied from 60 to −160 °C. A minimum threshold current occurs considerably below room‐temperature where the wavelength of the Fabry–Perot resonance of the cavity matches the wavelength of the maximum gain of the active region. The laser quantum efficiency increases for decreasing temperature, exhibiting a change of slope near the temperature of the threshold minimum.

High-power cw vertical-cavity top surface-emitting GaAs quantum well lasers

We have devised a novel vertical‐cavity top surface‐emitting GaAs quantum well laser structure which operates at 0.84 μm. The laser combines peripheral current injection with efficient heat removal and uses only the epitaxially grown semiconductor layers for the output mirrors. The structure is obtained by a patterned deep H+ implantation and anneal cycle which maintains surface conductivity while burying a high resistance layer. Peripheral injection of current occurs from the metallized contact area into the nonimplanted nonmetallized emission window. For 10‐μm‐diam emitting windows, ∼4 mA thresholds with continuous‐wave (cw) room‐temperature output powers ≳1.5 mW are obtained. Larger diameter emitting windows have maximum cw output powers greater than 3 mW. These are the highest cw powers achieved to date in current injected vertical‐cavity surface‐emitting lasers.

Strained quantum wells for polarization-independent electrooptic waveguide switches

A polarization-independent quantum well waveguide switch is demonstrated. By altering the composition and hence the degree of built-in strain, the bandgap of In/sub 1-x/Ga/sub x/As/InP quantum wells is engineered to produce equal field-induced refractive-index change in TE and TM polarizations. At the same time, the enhanced electrooptic effects characteristic of unstrained quantum wells are maintained, such that the voltage-length product for switching is only 3 V-mm. >

Characteristics of top-surface-emitting GaAs quantum-well lasers

Self-aligned top-surface-emitting vertical-cavity GaAs four-quantum-well lasers emitting at 850 nm with good room temperature CW characteristics are discussed. Deep buried damaged layers by proton implantation are used to control vertical conductivity profiles for efficient current injection at the active region. Minimum CW threshold is 1.8 mA. Maximum CW output power is 1.5 mW. Laser linewidth of 0.02 AA is measured using a scanning Fabry-Perot etalon. For all sizes of lasers, the full angle beam divergences of fundamental transverse modes are twice as large as those calculated from a diffraction formula using aperture diameters.<<ETX>>

Phosphorus ion implantation induced intermixing of InGaAs‐InP quantum well structures

We have studied P ion implantation induced intermixing of In0.53Ga0.47As quantum wells embedded between InP barriers. Data are presented for both standard furnace anneals at 650 °C and rapid thermal anneals at 750 °C. Low‐temperature photoluminescence and quantitative Auger electron spectroscopy were performed for furnace‐annealed samples for which photoluminescence shifts of ∼200 meV were in excellent agreement with the calculated band gap for the lattice matched composition determined by Auger spectroscopy. Photoluminescence studies of rapid thermal annealed samples yield an energy gap shift of ∼150 meV for annealing times of at least 10 s.

Deep-red continuous wave top-surface-emitting vertical-cavity AlGaAs superlattice lasers

Deep-red (770-nm) top-surface-emitting vertical-cavity AlGaAs lasers were fabricated and operated continuously at room temperature. An Al/sub 0.14/Ga/sub 0.86/As superlattice was used for an active-gain medium. Efficient current funneling was achieved by deep proton implantation. Continuous-wave (CW) threshold currents were 4.6 and 6.3 mA at 3.9- and 3.4-V bias for 10- and 15- mu m-diameter lasers, respectively. The maximum CW output power was >1.1 mW at room temperature without heat sink. Arrays of various top-surface-emitting lasers based on current funneling are expected to generate many applications for photonic switching, chip-to-chip communication, optical computing, and printing.<<ETX>>

High power laser‐amplifier photonic integrated circuit for 1.48 μm wavelength operation

We demonstrate a laser amplifier photonic integrated circuit having 370‐mW cw output power emitted in a single transverse mode a 1.48 μm wavelength, suitable for pumping erbium‐doped fiber amplifiers.

Resistance and mobility changes in InGaAs produced by light ion bombardment

We have measured sheet resistance and mobility changes for a series of In0.53Ga0.47As layers as a result of hydrogen, boron, and beryllium implantation. We find that boron and beryllium implantation can produce a two order‐of‐magnitude increase in sheet resistance due mainly to a decrease in mobility accompanied by a smaller decrease in the sheet carrier concentration. Hydrogen implantation results in a decrease in sheet resistance due to an increase in electron concentration accompanied by only a small mobility decrease. The increase in sheet resistance due to boron and beryllium implants is not large enough to have obvious application for device isolation.

Disordering of InGaAs‐InP quantum wells by Si implantation

Selective disordering of In0.53Ga0.47As‐InP multiple quantum well structures by ion implantation is demonstrated for the first time. As grown, annealed, and Si implanted and annealed samples were studied by transmission electron microscopy, optical absorption, and photoluminescence. A shift of the photoluminescence and absorption edge to higher energy was observed in implanted and annealed samples with respect to annealed only samples. This shift is attributed to a combination of disordering and Burstein–Moss effect.

Rapid thermal annealing of elevated‐temperature silicon implants in InP

Rapid thermal annealing of elevated‐temperature Si implants in InP is shown to result in higher donor activation and electron mobility with lower‐temperature–shorter‐anneal cycles than for room‐temperature implants. The reduced cycles (temperature below 800 °C with times of ∼10 s) also result in process simplification with negligible thermal surface degradation and insignificant Si diffusion. The results are demonstrated with a dual‐energy implant scheme applicable to field‐effect transistors and with a single‐energy heavy‐dose implant useful for achieving low‐resistance ohmic contacts.