James Flattery

Proposed size-effect high-electron-mobility transistor

Abstract We present a theoretical analysis of a high-electron-mobility transistor that uses the quantum size-effect to increase the energy gap of a thin InSb film that forms the channel of the device. The analysis is based on a considerable amount of available data. The device is predicted to have a cut-off frequency of the order of 439 GHz for a gate length of 0.5 μm. It is predicted to have a very high transconductance of 2.4 S per mm gate width, and a very high power handling capability of 1.4 A per mm gate width at a drain-to-source voltage of only 0.083 V, and it operates at 300 K.

Light amplification by a Cd3P2 cylinder fiber

We have fabricated fibers with an a few nm thick Cd3P2 semiconductor layer at the clear glass core glass cladding boundary. We have measured a gain of approximately 7.1 dB in a 4 mm long piece of this Semiconductor Cylinder Fiber (SCF) at a wavelength of 1550 nm. The fiber section was pumped from the side with a 38 mW laser operating at a wavelength of 980 nm. We have reason to believe that the test wavelength of 1550 nm is near the short wavelength end of about a few hundred nm wide gain curve. The SCFs have applications as broad band Fiber Light Amplifiers.

Cd3P2 Cylinder Fibers

We are currently working on Semiconductor Cylinder Fibers (SCF), fibers with a thin semiconductor layer at the glass core glass cladding boundary. We hope that these fibers can eventually be used as both S aturable Absorbers (SA) and Fiber Light Amplifiers (FLA). We use a rod and tube method for fabricating these fibers. The three fabrication process steps, semiconductor deposition, collapse, and fiber drawing have been working well since the summer of 1 999. We have mathematical models for the fabrication process steps that allows us to calculate the required temperatures and pressures used. The fabrication process is very reproducible.

Mathematical model of the absorption and gain in a Cd3P2 cylinder fiber

A theoretical analysis of the light absorption and gain mechanisms in a Cd 3 P 2 Semiconductor Cylinder Fiber is presented. The results of these calculations are in good agreement with previously published experimental data. Cd 3 P 2 has two direct energy gaps, which both influence the gain mechanism. Pump light can be used to reduce the absorption. Stronger pump light that generates more charge carriers will produce net gain (gain above absorption compensation). The fiber exhibits gain over a very wide light wavelength bandwidth.

Semiconductor cylinder fiber laser

Abstract. We fabricated a fiber laser that uses a thin semiconductor layer surrounding the glass core as the gain medium. This is a completely new type of laser. The In2Te3 semiconductor layer is about 15-nm thick. The fiber laser has a core diameter of 14.2  μm, an outside diameter of 126  μm, and it is 25-mm long. The laser mirrors consist of a thick vacuum-deposited aluminum layer at one end and a thin semitransparent aluminum layer deposited at the other end of the fiber. The laser is pumped from the side with either light from a halogen tungsten incandescent lamp or a blue light emitting diode flash light. Both the In2Te3 gain medium and the aluminum mirrors have a wide bandwidth. Therefore, the output spectrum consists of a pedestal from a wavelength of about 454 to 623 nm with several peaks. There is a main peak at 545 nm. The main peak has an amplitude of 16.5 dB above the noise level of −73  dB.

Gold cylinder fiber biosensor

We have fabricated and tested Gold Cylinder Fiber (GCF) bio sensors. The sensor fiber has a thin, approximately 3 nm to 5 nm thick, Gold alloy film layer at the glass core glass cladding boundary. One end of the fiber is etched to let the gold alloy cylinder protrude about 10 m. A Single Mode Fiber (SMF) is connected to the other end of the GCF. Light propagates through the SMF to a short section of GCF. The etched end of the GCF is dipped into the fluid to be analyzed. The reflected light from the sample returns back through the SMF to a spectrum analyzer.

Single eye and camera with depth perception

It is possible that each light sensor pixel in the eye has the capability of measuring the distance to the part of the object in focus at the pixel. One can also construct an electronic camera where each pixel can measure the distance to the portion of the object in focus at the pixel. That is, these devices have depth perception

Metal cylinder fiber

Light absorption spectrum measurements and the light intensity dependence of the light absorption spectrum of a fiber with a very thin gold film at the glass core glass cladding boundary are presented. The thickness of the gold film is less than the scattering length of electrons in this metal. The absorption spectrum appears to be strongly light intensity dependent. We also observed the mode structure of light propagating through the gold film. Our fabrication process can produce large area very thin metal films that are very difficult to produce by other methods.

Wide band gain and amplified stimulated emission measurements in Cd3P2 cylinder fiber

We have measured a net gain of 19.5 dB in a 4 mm long piece of Cd3P2 Semiconductor Cylinder Fiber (SCF) at a wavelength of 1550 nm. The fiber was pumped from the side with a 100 mW, 832 nm laser. Side pumping is very inefficient since only a small portion of the pump light is absorbed by the very thin, approximately 6.694 nm thick, semiconductor film. However, this pumping arrangement is very convenient and does not require wavelength sensitive input and output couplers. We also measured the absorption spectrum. The absorption spectrum is in good agreement with a theoretical model. The absorption spectrum exhibits a step due to the two direct energy gap conduction bands of the Cd3P2 semiconductor film.

Metal strip polarizing fibers

We successfully placed a metal strip along the core of an optical fiber, see Fig. 1. These devices can be used as polarizers. Light polarized parallel to the metal strip is absorbed while light polarized perpendicular to the metal strip is absorbed less. Potentially large ratios of transmitted to absorbed light can be achieved in relatively short pieces of fiber. The Metal Strip Polarizing Fibers (MSPFs) are typically about 5 mm long. We report both on the fabrication process and some preliminary test.