Robert J. Phelan

GaAs SCHOTTKY BARRIER AVALANCHE PHOTODIODES

Uniform avalanche Schottky barrier photodiodes have been fabricated by plating a thin layer of platinum on GaAs and forming a guard ring by proton radiation. Operating at a gain of 100 these photodiodes exhibit gain‐bandwidth products greater than 50 GHz and enhanced signal to noise ratio in excess of 30 dB. The observed variation on the spectral response with bias can be accounted for by a change in the absorption of the Schottky barrier diode.

InSb MOS Infrared Detector

Infrared photovoltaic response and high quantum efficiency have been observed in a large‐area InSb, metal‐oxide‐semiconductor structure. Spectral measurements indicate that the response is due to the generation of electron‐hole pairs in a depletion region of the n‐type InSb at the InSb‐oxide interface. Pulsed current measurements yield a clear diode characteristic and the overall results are equivalent to what one would expect to obtain from a photodiode in series with a MOS capacitor.

PbSe diode laser

Abstract Laser action has been observed from diffused diodes of properly annealed PbSe. At approximately 12°K, a laser line at 8.5 μ and a well-defined mode structure were evident above a threshold current density of 5600 A cm-2. A resolution-limited spectral line width of 65 A was measured.

Subnanosecond electrical modulation of light with hydrogenated amorphous silicon

A silicon thin‐film interferometer structure is used to demonstrate subnanosecond electrical modulation of light. Both thermally and electrically induced modulations are reported. An electrically induced change in refractive index of 4.7×10−4 is observed.

InSb-GaAsP infrared to visible light converter

A solid-state sandwich composed of a capacitor-InSb diode detector-GaAsP diode emitter is proposed and demonstrated for efficiently converting infrared signals of wavelengths to 5.3 µ into visible 0.6- to 0.7-µ radiation. The device integrates the low-level incident radiation and delivers it to the emitter as high-current pulses.

Relative Intensity Noise of an InGaAsP Laser over a 22 GHz Bandwidth at Cryogenic and Room Temperature

Cryogenic operation of semiconductor lasers offers the potential for greater bandwidth due to improved frequency modulation response,1,2 lower threshold current, and higher power efficiency3 over that of room temperature operation. The 3- dB electrical modulation bandwidth can be determined from the relaxation oscillation frequency as located from the peak in the relative intensity noise (RIN) spectrum.4 In this report we show that the cryogenic RIN of a commercial 1.5 μm InGaAsP laser is significantly reduced below room temperature values over a major portion of a 22 GHz measurement bandwidth, yielding increased potential for ultrahigh speed modulation. Low RIN lasers are also useful for determining the optimum performance of advanced photodetectors, for measuring noise figure of optical fiber amplifiers, and as reference standards for the comparison and evaluation of RIN measurements.