Fiber-optic techniques for remote sensing are now being accepted and developed for a wide range of applications. Traditional sensor technology relies on electrical components to provide the measurement of changing environmental conditions. However, when operating in remote and harsh environments, electrical sensors have a variety of limitations such as power requirements and short lifetime. In contrast, fiber-optic sensors are passive devices that are environmentally stable and have a long lifetime. The fiber Bragg grating (FBG) is a particular type of fiber-optic sensor that can be adapted to measure parameters such as temperature, pressure or strain. The measurement is encoded with the wave-length of the optical signal reflected from the FBG. Consequently, the method of measuring the absolute optical wavelength is a critical component of the fiber-optic sensing system. To reliably detect very small changes in the environment at the sensor, the interrogation system must provide accurate and repeatable wavelength measurements. The interrogator also must be robust so that it can be deployed in the field as well as in the laboratory. Performance of a fiber Bragg grating interrogator based on Michelson interferometry is discussed along with the advantages of this technique.