Generation of thermally stable defects can be quite difficult when dealing with laser diodes as they generate heat continuously when operating. One of the major problems of using this technique is generating stable defects. It is reported that ion implantation at low temperature results in more stable damage formation 11. The damage as a result of ion bombardment can increase the resistivity of the III-V material ridge walls for example, which in turn can improve the electrical performance of ridge side walls and hence reduce the leakage current. Researchers used ion implantation to improve the current confinement of lasers 9, 10. To improve the output power, ion implantation is used for making high resistive III-V materials 8. The power profile problem of the AMQW laser diodes limits the use of these lasers in certain applications. Despite the wide tuning range, the power profile of InGaAsP/InP asymmetric multiple quantum well (AMQW) ridge waveguide laser suffers from low power problem. This broad gain profile results in an improved wavelength tuning range compared with conventional QW or multiple quantum well (MQW) structures 7. Each QW of different width or composition gives a different gain characteristic and the sum of all the gain curves can yield a broad net gain curve 3, 4, 5, 6. ![]() Asymmetric multiple quantum well (AMQW) lasers provide broad tunability since they consist of several quantum wells (QW) of different widths or compositions. Broad tunability in diode lasers are associated with a broad gain profile. They are promising light sources for communication, sensing, and medical applications. AMQW diode lasers have QWs of different compositions or different thicknesses in the same device. Asymmetric MQW laser diodes are special cases of MQW diode lasers they were first demonstrated by Ikeda 2 et al. The need for improvement in device performance such as single mode operation, power and wavelength tunability was the driver to develop high quality MQW diode lasers. ![]() Multiple quantum well (MQW) lasers were first reported by Holonyak 1 et al. The proposed method can be efficient but a passivation technique needs to be developed for these devices. The experimental data did show improvement in the current injection efficiency but also showed creation of recombination centers that reduce the temperature and power improvement. ![]() Experimental data however, give less optimistic results. This temperature improvement is significant and can lead to a significant improvement of the laser output power. The simulation data also, showed a reduction of nearly 10☌ in the maximum temperature of these devices compared with original AMQW devices. The simulation data for the proposed method showed that it is possible to increase the current injection efficiency up to 90 %. Since the ridge structure is an essential part of these type of laser diodes, we proposed a forced electrical confinement method to improve current injection efficiency of these lasers. A FlexPDE simulation model showed that the main reason for this poor current injection efficiency is the ridge structure. The current injection efficiency of such lasers in average is 18 %. ![]() 100 nm Broadly tunable InGaAsP/InP asymmetric multiple quantum well (AMQW) ridge waveguide laser diodes has limited applications because of its low output power problem.
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