Quantum Well Intermixing Process Research Articles

Postgrowth control of the quantum-well band edge for the monolithic integration of widely tunable lasers and electroabsorption modulators

We describe a quantum-well intermixing process for the monolithic integration of various devices, each with a unique band edge. The process involves a single ion implant followed by multiple etch and anneal cycles. We have applied this method to design and fabricate widely tunable sampled-grating distributed Bragg reflector lasers with integrated electroabsorption modulators. The devices employ three unique band edges, and demonstrate exceptional tuning, gain, and absorption characteristics.

A quantum-well-intermixing process for wavelength-agile photonic integrated circuits

Wavelength-agile photonic integrated circuits are fabricated using a one-step ion implantation quantum-well intermixing process. In this paper, we discuss, the issues in processing optimized widely tunable multisection lasers using this technique and present the results achieved using this process. This quantum-well intermixing process is general in its application and can be used to monolithically integrate a wide variety of optoelectronic components with widely tunable lasers.

Quasi-phase matched second-harmonic generation in an AlxGa1−xAs asymmetric quantum-well waveguide using ion-implantation-enhanced intermixing

Quasi-phase matched second-harmonic generation in the copropagating geometry is demonstrated in an asymmetric quantum-well waveguide. Modulation of the nonlinear susceptibility along the waveguide was achieved using a patterned quantum-well intermixing process. Photoluminescence measurements of the quantum-well bandedges indicate that a grating of alternating regions of intermixed and as-grown asymmetric quantum wells was produced for periods between 2 and 12 μm. The variation of the second-harmonic light intensity generated by guided incident light between λ=1480 and 1600 nm was measured. The resulting second-harmonic spectra show sharp quasi-phase matching resonances for grating periods near 3 μm, demonstrating that a periodic modulation of the quantum-well nonlinear susceptibility was produced.

High-spatial-resolution quantum-well intermixing process in GaInAs/GaInAsP laser structure using pulsed-photoabsorption-induced disordering

Raman spectroscopy was used to study the spatial resolution of pulsed-photoabsorption-induced quantum-well intermixing in a GaInAs/GaInAsP laser structure. A differential band gap shift of up to 60 meV has been obtained from a sample masked with SixNy/Au and exposed to the laser irradiation. Intermixing was detected in the irradiated regions through the shift of GaAs-like modes to lower frequencies. In addition, the intermixing induced GaInP longitudinal optical modes in the irradiated regions, which is evidence of the intermixing between the upper GaInAs cap and the GaInAsP layer. The spatial resolution of this process, which was obtained from micro-Raman spectra when scanned across the interface of the intermixing mask, was found to be better than 2.5 μm.

Reduction of InGaAs/GaAs laser facet temperatures by band gap shifted extended cavities

Reflectance modulation measurements have been used to determine facet temperatures of InGaAs/GaAs double quantum well (QW) graded-index separate-confinement heterostructure ridge-waveguide lasers possessing band gap tuned passive cavity sections. We find that the incorporation of transparent extended cavities, produced by ion-implantation enhanced QW intermixing, significantly decreases the laser facet temperatures. The reduced photoabsorption occurring at the facets, achieved by the QW intermixing process, should lead to increases in both the maximum optical power levels and device longevity prior to the onset of catastrophic failure.

Integration process for photonic integrated circuitsusing plasmadamage induced layer intermixing

A new quantum-well intermixing process in GaAs/AlGaAs structures, based on ion bombardment damage, has been developed. Bandgap tuned lasers and extended cavity lasers have been fabricated. Results show that the quality of the material is still high after intermixing. Losses as low as 18 dB cm-1 have been measured in the passive waveguides of the extended-cavity lasers.