The objective of this program was to develop, fabricate, ande deliver one complete 1000 Megabit per second Mbps brassboard modulator package for use in the 1000 Mbps Pulse Gated Binary Modulation brassboard laser communications system for a 1973 capability demonstration. The modulator package consisted of two 500 Mbps modulators with optical multiplexing to achieve the 1000 Mbps capability. One of the 500 Mbps modulators was a GFE item from AF Contract F33615-72-C-1380. The second 500 Mbps unit was fabricated under the scope of this effort. The program included modification and packaging of the GFE modulator as a brassboard unit and construction of a second brassboard modulator unit. Each modulator unit included a modulator subassembly, 500 Mbps modulator driver, automatic electronic compensator, manual electrical compensator, manual thermal differential compensator, and temperature controller. The modulators were combined on a single plate with the necessary input, output, and delay optics to provide a 1 Gibabit bit per second Gbps modulated optical data stream. A power supply for the modulators was built as a separate unit. The assembled 1 Gbps modulator package was designed to interface with the laser transmitter and transmitter electronics of the brassboard baseband digital laser communication system.