G. Benjamin Hocker

Unidirectional star coupler for single-fiber distribution systems

The design and construction of a unidirectional star coupler for single-fiber distribution systems are described. A rectangular mixing section is required to obtain uniform output distribution. Four-port stars have been constructed with losses only (1/2) to 1 dB greater than packing fraction. For any given input, outputs are uniform to within about +/-1 dB.

Acoustic desensitization of optical fibers by means of nickel jackets

In the field of fiber optic acoustic sensors, a method for acoustic desensitization of certain sections of optic fibers by means of the use of higher elastic modulus coatings, such as an electrodeposited nickel jacket.

A MEMS-based correlation radiometer

We describe the development of a MEMS-based correlation radiometer for remote detection of chemical species. The radiometer utilizes a new type of MEMS programmable diffraction grating called the Polychromator. The Polychromator contains an array of 1024 electrostatically actuated reflective beams that are 10 microns wide by 1 cm long, and have a vertical travel of approximately 2 - 4 microns. The Polychromator grating is used to replace the reference cell of conventional correlation radiometry. Appropriate programming of the deflection profile of the grating array enables the production of any spectral transfer function desired for the correlation measurement. Advantages of this approach to correlation radiometry include the ability to detect multiple chemical species with a compact instrument, the ability to optimize the reference spectra to eliminate chemical interferences, and the ability to produce reference spectra for hazardous and transient species.