Optical components and systems manufacturer Gooch & Housego announced Friday that it will acquire Boston-based EM4 Inc. Financial terms were not disclosed; the transaction is expected to be completed by the end of January. EM4 makes optoelectronic components and subsystems for customers in the US and Europe. Its products include lasers, detectors and high-frequency receiver or transmitter electronics, primarily for aerospace and defense extreme environment applications, but also for the industrial and life sciences sectors. Gooch and Housego (G&H) said EM4's active technology systems are an ideal complement to its passive fiber optics technologies, and the acquisition will strengthen G&H's presence in the aerospace and defense markets and allow it to migrate from its largely component-level product set of today to modules and subassemblies in the future. G&H currently has eight facilities, five in the US and three in Europe, manufacturing acousto-optics, electro-optics, fiber optics, precision optics, RF electronics, optical modules & subsystems, imaging & light measurement systems and providing materials engineering & crystal growth. For more information, visit: www.goochandhousego.com