Efficiency of surface-pumped backward optical parametric oscillators and amplifiers in gallium arsenide/aluminum gallium arsenide.

摘要

The backward optical parametric oscillator (BOPO), in which the signal and idler waves propagate in opposite directions, has unique features and potentially significant advantages over conventional forward OPOs. However to date, over 30 years since it was first proposed, there is still no experimental demonstration of a BOPO.;The most interesting feature of the BOPO is the potential for oscillation without mirrors. The counter-propagating waves amplify each other, closing a distributed feedback loop. This eliminates the stability problems associated with cavity axial modes. In addition, the BOPO has a dramatically narrower gain bandwidth than forward OPOs. These two properties combined could make it an excellent source for spectroscopy and other applications.;This thesis examines the feasibility of a waveguide structure in GaAs/AlGaAs, pumped through the surface, for achieving backward oscillation. Optimization of device parameters and experimental design are presented for both backward amplifier and oscillator, neither of which was observed. We show that the surface pumped geometry, while providing the necessary phasematching, has inherently low efficiency and is very sensitive to growth non-uniformity. While it should be possible to achieve the first experimental demonstration of a backward OPO in this geometry, a highly uniform material and careful experimental design are required to keep the oscillation threshold below the damage threshold.