Vertical-cavity electrically driven lasers with three GaInAs
quantum wells and diameters of several μm exhibit room-temperature pulsed current thresholds as low as 1.3mA with 958 nm output wavelength.

Low-Threshold Electrically Pumps Vertical-Cavity Surface-Emitting Microlasers

We demonstrate record high pulsed output power exceeding 530 mW from an electrically pumped phase‐coupled 8×8 vertical cavity surface emitting laser array (SELA) at room temperature. Three array types are compared: an 8×8 pixellated SELA(PSELA), an 8×8 grid contact SELA(CSELA), and a 78 μm×78 μm single broad area SEL(BSEL) emitter. The CSELA operating in a phase‐coupled supermode exhibits the lowest threshold current (100 mA) and voltage (1.6 V), highest damage threshold and a smooth L‐I characteristic with differential quantum efficiency ηd≳27%, the BSEL has the largest output power≳580 mW and a large ηd≳48%, the PSELA exhibited a large voltage with the largest ηd≳80%.

High‐power coherently coupled 8×8 vertical cavity surface emitting laser array

We demonstrate antiguided coupling of two adjacent vertical-cavity surface-emitting lasers (VCSELs), obtaining a 1×2 phase-locked array at 869 nm. The lateral index modification required for antiguiding is achieved by a patterned 3 nm etch performed between two epitaxial growths. In contrast with prior coupled VCSELs, adjacent antiguided VCSELs can emit in phase and produce a single on-axis lobe in the far field. Greater than 2 mW of in-phase output power is demonstrated with two VCSELs separated by 8 μm. Moreover, phase locking of two VCSELs separated by 20 μm is observed, indicating the possibility of a promising class of optical circuits based upon VCSELs that interact horizontally and emit vertically.

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Two-element phased array of antiguided vertical-cavity lasers

4×4 antiguided phase-locked vertical-cavity surface-emitting laser (VCSEL) arrays have been fabricated by a selective etching process and metalorganic chemical vapor deposition regrowth. Stable, diffraction-limited output is observed corresponding to either in-phase or out-of-phase mode operation, depending on the interelement spacing width. Calculations indicate resonant leaky-wave coupling occurs for interelement spacings corresponding to an integral number of half-waves of the radiation leakage from each VCSEL region, and the use of interelement loss is effective in suppressing nonresonant modes.

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Two-dimensional phase-locked antiguided vertical-cavity surface-emitting laser arrays

Photonic crystal patterns containing two defects were fabricated within a large gain area in vertical cavity surface emitting lasers. By designing effective refractive index changes in the region between the defects through cavity shifts caused by photonic crystals, it was possible to coherently couple laser light output from the defects. This enables a novel way to fabricate coherently coupled laser arrays.

Coupled-defect photonic crystal vertical cavity surface emitting lasers

Two-dimensional arrays of 3*3 vertical cavity surface emitting GaAs-AlGaAs lasers with 7- mu m center spacing are described. The lasers were grown by molecular beam epitaxy and contain one grown GaAs-AlAs mirror under the active layer and a second, thermally deposited, high-reflectivity, SiO/sub 2/-Si mirror on top of the epitaxial layer. The array has a 295-K threshold of 90 mA, corresponding to 10 mA per laser. The individual lasers in the array have Gaussian beam profiles both spatially in the near field and angularly in the far field. When all the lasers in the array are operating in a coupled manner, the emission exhibits a lobed far-field pattern with a 5 degrees separation in the direction parallel to the contact edge and a 2.5 degrees separation perpendicular to the contact edge. >

G.J. Zydzik

Papers

Characteristics of single- and two-dimensional phase coupled arrays of vertical cavity surface emitting GaAs-AlGaAs lasers