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Alice Bernard

Towards an electrically injected optical parametric oscillator

Published on 10 July 2018
Thesis presented July 10, 2018

The work presented in this thesis deals with the design, fabrication and characterization of sources intended to function as both laser diodes and optical parametric oscillators. These lasers are designed to emit on a higher order mode to allow parametric frequency conversion with fundamental modes of the guide at half frequency. The laser diode and OPO share the same optical cavity; to ensure phase matching and correct nominal structure deviations induced during epitaxial processing, the ridge width is used as a control parameter of the effective indices. The proposed diodes are therefore narrow (3-5 μm) and etched deeply. Consequently, it is potentially interesting to use quantum dots to limit non-radiative recombination on the sidewalls. In the context of this work, we have designed diodes based on this principle for the two GaAs/AlGaAs and InGaAsP/InP systems, which respectively allow to potentially obtain an OPO emission in the vicinity of 2 μm or 3 μm. In the case of InGaAsP/InP, we previously studied the refractive index of InGaAsP alloys in a wavelength range not covered by literature to this day. This data was acquired via effective m-line index measurements of InGaAsP guiding layers epitaxially grown on and lattice-matched to an InP substrate. For optimized laser-OPO structures, simulations show that the OPO threshold should be obtained for an intracavity pump power of a few hundred mW, which is realistic to achieve for state-of-the-art laser diodes. We have studied the electro-optical properties of GaAs/AlGaAs quantum well laser diodes made on the basis of our designs; the observation of the laser effect on the TE2 mode validates the original vertical design of our laser diodes. For the manufacture of narrow-ridge lasers-OPOs, we have developed new manufacturing processes on the Plateforme Technologique Amont (Upstream Technology Platform, CEA - Grenoble), including deep etching (> 10 μm) by ICP-RIE. Finally, we have proposed an alternative diode-OPO concept, comprising distinct laser and OPO cavities coupled by an adiabatic taper

M-lines, Efficient index measurement, InGaAsP, Laser diode, Optical Parametric Oscillator, Molecular beam epitaxy, Integrated photonics, AlGaAs

On-line thesis.