Non-selective oxidation of AlGaAs heterostructure under oxygen-enhanced wet thermal conditions has been combined with deep dry etching via reactive ion etching (RIE) to achieve a high index contrast (HIC) ridge waveguide (RWG). The HIC RWG provides laser diodes with both strong optical confinement due to the high index contrast, and strong electrical confinement by eliminating current spreading. The oxide also effectively passivates the active region sidewall exposed after etching through the WG core layers. More importantly, the roughness of the sidewall, which leads to strong optical scattering losses in an HIC waveguide, has been greatly reduced by the smoothing action of the non-selective oxidation process. With such a structure, high performance straight laser diodes have been demonstrated on both quantum well (QW) and quantum dot (QD) heterostructures. In particular, a 4 mm wide QD laser fabricated with this deep dry etch plus non-selective oxidation process shows a 1.8 times lower threshold current density Jth than similar HIC lasers passivated with deposited SiO2, and 6.5 times lower than conventional (shallow etched) index guided lasers. The use of a HIC structure is absolutely critical to the realization of low bend loss curved waveguides and laser resonators. With a specially designed half-racetrack ring resonator (R3) pattern, the dependence of the radiative bend loss on the bend radius and ridge width is carefully studied. By implementing e-beam lithography for the patterning process, a half-racetrack-ring resonator with a 3.1 mm ridge width and a record small bend radius of r=3 mm is demonstrated. A new experimental method is demonstrated for characterizing the radiative bend loss from analysis of efficiency data of half-R3 lasers with multiple cavity lengths. The radiative bend losses are extracted from an inverse efficiency 1/hd vs. length L plot for half-R3 lasers with r=150, 100, 50, 25 and 10 mm and three different ridge widths. In addition to the expected bend loss dependence on ring radius, we observe a clear trend of increased bend loss with increasing RWG width and number of WG modes supported. Finally, a full-ring laser with a 150 mm radius is fabricated using the developed e-beam lithography, deep dry etch via RIE and non-selective oxidation processes. The device shows a low Jth of 719 A/cm2, 25% lower than the best reported full ring laser having the same ring radius and a similar deep-etched waveguide structure fabricated using a deposited insulator.