In some implementations, an optical device (e.g., a monolithic master oscillator power amplifier (MOPA) diode) may include a first facet, one or more gratings, an amplifier structure terminated with a second facet, and an oscillator array that includes multiple singlemode oscillators coupled to the first facet and to the one or more gratings. In some implementations, the multiple singlemode oscillators may be configured to generate multiple seed beams and to transmit the multiple seed beams into the amplifier structure through the one or more gratings.