Gain slope compensator for spectrally linear optical power equalization

We present a micromechanical optical interference device that produces changes in the slope (in dB) of its transmitted spectrum via a single voltage control, without changes in attenuation level, a Spectrally Linear Optical Power Equalizer, or SLOPE device. Simple linear power equalization is sometimes all that is required in optical networks, especially in optical amplifiers, and this device can perform this function inexpensively and with easier control than multi-element equalizers. The device element is a vertically moving membrane similar to the MARS modulator. The reflectivity of the element is varied by the adjustment of the air gap via a bias applied to the element's electrode. The element can be thought of as a thin-film optical stack where one of the films (the air gap) is variable. Its reflectivity is transmitted via a dual fiber ferrule arrangement, in which the light comes into the device in one fiber, is reflected off the device and focused onto the outgoing fiber.