J.C. Dries

Monolithic integration of a quantum-well laser and an optical amplifier using an asymmetric twin-waveguide structure

We demonstrate the monolithic integration of a 1.55 /spl mu/m wavelength InGaAsP-InP multiple-quantum-well (MQW) laser and a traveling-wave optical amplifier using an asymmetric, vertical twin-waveguide structure. The laser and amplifier share the same strained InGaAsP MQW active layer grown by gas-source molecular beam epitaxy, while the underlying passive waveguide layer is used for on-chip optical interconnections between the active devices. The asymmetric twin-waveguide structure uses the difference in modal gains to discriminate between the even and odd modes.

Strain-compensated InGa(As)P-InAsP active regions for 1.3-μm wavelength lasers

The demonstration of an optimized strain compensated multiple-quantum-well (MQW) active region for use in 1.3-/spl mu/m wavelength lasers is described. Utilizing narrow bandgap tensile-strained InGaAsP instead of wide bandgap InGaP barriers in strain-compensated lasers, we observe a reduction in threshold current density (Jth) from 675 to 310 A/cm/sup 2/ and in T/sub 0/ from 75 K to 65 K for 2-mm long seven quantum-well devices. Additionally, the lowest reported Jth for MBE grown 1.3-/spl mu/m wavelength lasers of 120 A/cm/sup 2/ for single-quantum-well (SQW) 45-mm-long lasers was attained.

Variations in the photon-counting performance of InGaAs/InP avalanche photodiodes

Summary form only given. In this paper we present new data on the photon-counting performance of a number of commercial APDs, designed for linear operation in data communications applications at 2.5 Gb/sec. These data include dark count rate, quantum efficiency, and jitter, as well as the variation of these parameters with temperature and bias voltage. We show that current InGaAs/InP APDs of the appropriate design are well suited to many practical applications of single-photon counting in the 1.0 to 1.6 /spl mu/m wavelength band.

Two-dimensional indium gallium arsenide avalanche photodiode arrays for high sensitivity, high speed imaging

A 32 /spl times/ 32 element InGaAs focal plane array was demonstrated. These arrays may find application in 3-dimensional imaging systems. APD arrays will be advantageous in these systems since the bandwidths required of the readout integrated circuits push their noise performance into the regime where avalanche photodiodes are useful. Further work is underway on both readout integrated circuits for the arrays, as well as integrated microlenses that will improve the fill-factor of the arrays.

Strain compensated In/sub 1-x/Ga/sub x/As (x<0.47) quantum well photodiodes for extended wavelength operation

The use of highly strained (-1.8%) InGaAs quantum wells for the detection of optical radiation beyond the InP lattice-matched bandgap of 1.65 /spl mu/m wavelength is reported. Excellent crystal quality for up to 50 quantum wells is maintained through strain compensation using tensile InGaP. Transmission electron microscopy and double crystal X-ray diffraction reveal smooth interfaces and no observable defects for In/sub 0.83/Ga/sub 0.17/As layers with widths less than 80 /spl Aring/. Single-pass quantum efficiencies of 33% have been achieved at 1.95 /spl mu/m wavelength using a 50 period, strain compensated p-i-n multiple-quantum well structure in a top illuminated mesa device.

Demonstration of a 40 Gb/s, 4 channel optical receiver array

We demonstrate a four-channel DWDM optical receiver array operating at 10 Gbps/channel with a sensitivity of -17 dBm and an aggregate data rate of 40 Gbps. The optical receiver is a hybrid integrated device consisting of a monolithic InGaAs p-i-n photodiode array hybridized to individual InP heterojunction bipolar transistor based transimpedance amplifiers.

Confocal SWIR imaging and 3D range finding using InGaAs P-i-N and APD detector arrays

In this presentation, we discuss the design and fabrication of a densely packed array of InGaAs APDs where each pixel contains both a low-noise PIN imaging detector and a high band-width APD.

Low-loss, low-threshold 0.98 /spl mu/m wavelength InGaAsP/InGaP/GaAs broadened waveguide lasers grown by GSMBE

We describe the design and experimental results for broadened waveguide (BW) high-power, low-loss, low threshold current 0.98 /spl mu/m-aluminum-free InGaAsP/InGaP/GaAs lasers. The dramatic decrease in the internal losses with an increase in the width of the waveguide layer for a SCH-MQW structure, is attributed to lower free-carrier absorption due to the reduced overlap of the optical mode with the highly doped cladding regions. The BW lasers grown with both InGaAsP and GaAs waveguides show lower internal loss and threshold current than those designed for optimum optical confinement factor within the QW region. We report a record low internal loss of 2.2 cm/sup -1/ and highest CW output power of 6.8 W for a InGaP/GaAs laser grown by GSMBE. We also report the highest quasi-continuous output power of 13.3 W measured for a single 100 /spl mu/m aperture, 0.8-0.98 /spl mu/m Al-free laser diode, grown by either MBE or MOCVD.

Low threshold InAsP/InGaP/InGaAsP/InP strain-compensated and compressively-strained 1.3 /spl mu/m lasers grown by GSMBE

We demonstrate, for the first time, strain-compensated InAsP/InGaP/InGaAsP/InP SCH-MQW lasers grown by Gas Source Molecular Beam Epitaxy (GSMBE). Also compressively strained InAsP/lnGaAsP/InP 1.3 /spl mu/m lasers with record low threshold current densities were obtained. The threshold current density of 210 A/cm/sup 2/ for compressively strained broad-area laser with 2.0-mm cavity was lower than the previously reported InAsP-based lasers grown by GSMBE.

Temperature and bias characteristics of p-i-n optical modulators for free-space optical communications

Operational characteristics of InGaAs/InAlAs based MQW modulators, with different device designs, for a wide temperature range (-40/spl deg/C to 70/spl deg/C) are reported. The modulator peak extinction ratio wavelength is shown to be a linear function of temperature.