Violet blue laser mini‐bars

Abstract

We demonstrate the construction of violet blue multi‐quantum‐well (MQW) InGaN/GaN laser mini‐bars, a novel system in nitride‐based devices. It consists of three laser stripes, closely spaced with 40 μm pitch. The width of the stripe was 3 microns. Structures were fabricated on high pressure grown, low dislocation density substrates. Under cw operation the measured spectra demonstrate sharp, almost single line emission (FWHM ∼ 1.43 Å). Measurements of the optical far field pattern revealed that when operated under threshold the device was emitting light from all three stripes, whereas during lasing we observed the optical mode only in the area of the middle laser stripe. The behaviour of optical mode suggests the formation of the supermode (coherent emission from all three devices). The maximum optical output power was 270 mW at 402 nm and the slope efficiency was 0.7 W/A. This device offers the possibility to overcome the optical output power limit, characteristic for narrow stripe devices. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

InGaN mini‐laser diode arrays with cw output power of 500 mW

“…Details of the epitaxial design are given in Table 1. In contrast to our old generation structures for which weak transversal waveguiding properties resulting in a leakage of the optical mode were indentified [3,4], we improved the design by utilizing the plasmonic properties of a highly conductive substrate. GaN substrate served as a plasmonic bottom cladding due to the free-carrier induced reduction of its refractive index and allowed to confine the optical mode in the original waveguide of the device, without the use of thick AlGaN cladding.…”

“…These arrays systems, based on conventional arsenic materials, are wellknown devices, which have been developed and improved for almost four decades [2]. In case of gallium nitridebased structures, reports on their fabrication are relatively recent, our previous reports [3,4] and this study are focused on a simple, three emitters violet-blue multiquantum-well (MQW) InGaN/GaN laser mini array.…”

Impact of thermal crosstalk between emitters on power roll-over in nitride-based blue-violet laser bars

“…The thermal crosstalk effect has been analysed in twodimensional arsenide arrays composed of vertical-cavity surface-emitting lasers designed for 980 nm [14][15][16], in onedimensional arrays of phosphide distributed-feedback lasers designed for 1.55 μm [17] and in analogous arrays of nitride EELs designed for 410 nm [18]. Problems with the operation of nitride laser bars, probably caused by thermal crosstalk, have also been reported by Unipress [10,11]. Thermal crosstalk has a much wider range than electrical or optical crosstalk [14].…”

“…In 2002, Sony obtained power of 4.2 W from such a nitride laser array containing 44 stripes in CW operation at RT [9]. Much better performance can be achieved in arrays produced on expensive GaN substrates [2,[6][7][8][10][11][12][13], which have lower dislocation densities and lower thermal resistances. In all laser arrays, however, it is important that the emitters should not be arranged too closely to one another, mainly to avoid mutual thermal crosstalk.…”

A High Power InGaN-Based Blue-Violet Laser Diode Array with a Broad-Area Stripe

“…InGaN-based laser diodes with output power of several hundreds of milliwatts are available. [7] However, laser diodes with a higher output light power of several watts are still expected especially in the fields of materials processing, projection displays, and medical treatment. There are usually two different approaches to raise the output power of the laser diodes.…”