We demonstrate very high reliability level on 980-1060nm high-power single-mode lasers through multi-cell tests. First,
we show how our chip design and technology enables high reliability levels. Then, we aged 758 devices during 9500
hours among 6 cells with high current (0.8A-1.2A) and high submount temperature (65°C-105°C) for the reliability
demonstration. Sudden catastrophic failure is the main degradation mechanism observed. A statistical failure rate model
gives an Arrhenius thermal activation energy of 0.51eV and a power law forward current acceleration factor of 5.9. For
high-power submarine applications (360mW pump module output optical power), this model exhibits a failure rate as
low as 9 FIT at 13°C, while ultra-high power terrestrial modules (600mW) lie below 220 FIT at 25°C. Wear-out
phenomena is observed only for very high current level without any reliability impact under 1.1A.
For the 1060nm chip, step-stress tests were performed and a set of devices were aged during more than 2000 hours in
different stress conditions. First results are in accordance with 980nm product with more than 100khours estimated
MTTF. These reliability and performance features of 980-1060nm laser diodes will make high-power single-mode
emitters the best choice for a number of telecommunication and industrial applications in the next few years.
In this paper, we present first experimental results obtained on two and three tenninal edge-coupled InPfInGaAs heterojunction phototransistors showing that these devices seem very promising for microwave and millimeter wave applications.
Keywords : phototransistor , heterojunction, edge-coupled, microwave, millimeter wave, GaInAS/InP, photodetector
In this paper, we present the optical behavior of waveguide PIN photodetectors for millimeter wave applications. The side illumination of these devices allows us to overcome the problem encountered with classical PIN top illuminated photodetectors, which is the compromise between high cut-off frequency and high responsivity. This is the reason why we have modeled PIN waveguide photodetectors grown on InP substrate. Our modeling is based on 3D and 2D FD Beam Propagation Method to describe the propagation of light in the photodetector and on the solution of classical semiconductor equations to describe the electrical behavior of the device. The model is applied to InP P+/GaInAs N-/InP N+ and InP P+/GaInAsP P+/GaInAs N-/GaInAsP N+/InP N+ structures. Cut-off frequencies up to 90 GHz can be obtained for very small devices, typically 12 micrometers for the device length and 5 micrometers for the rib width with 0.3 micrometers thickness of GaInAs absorbing layer, by neglecting parasitic effects due to boundary pads. This is also valid for structures with smaller ribs using a constant surface area. The external quantum efficiency of such a device is strongly dependent on the device structure (GaInAsP thickness, monomode or multimode structure), and also on the conditions of injection of light (width and position of the optical spot, angle of the optical beam with the device). A complete analysis of the quantum efficiency versus the influence of GaInAsP thickness, device length, GaInAs thickness, and optical injection has been performed. It was found that, using lens ended optical fiber, multimode waveguide structures are better devices compared to monomode ones, and can lead to quantum efficiency higher than 90%.