The Atacama Large Millimeter Array (ALMA) project's size (30 km in diameter), and scope (66 antennas linked to create an array) led to many technological challenges during its design and construction. One of these was how to generate, distribute, and stabilize the Local Oscillator (LO) necessary to maintain coherence over the entire array. This presentation will offer a brief overview of how we were able to harness a number of photonics-based tools to achieve a timing and synchronization level of approximately 18 femtoseconds for this state-of-the-art instrument.