A ten-element InGaAs strained-layer single quantum well laser phased array coupled with corner reflectors (CRLA) was designed and fabricated by using reactive ion etching (RIE). A far-field pattern with main single lobe was obtained in a larger current range up to 4 ×threshold. The narrowest beam width measured for the main lobe was 0.64°, near the diffraction limit. The mode characteristicsof CRLAs were analyzed and simulated by using the Perturbation theory, taking into consideration the inter-coupling between longitudinal and lateral modes caused by the corner reflectors, and the anti-index guiding caused by carrier injection into InGaAs active layer. The results show that the coupling with corner reflectors is a new kind of coupling mechanisms for phase-locked laser array; and the main lobe corresponds to in-phase locking, while the side lobes correspond to the higher order eigenmodes, as the result of periodical perturbation.