Gerald M. Borsuk

Photosensor Array For Integrated Optical Spectrum Analyzer Systems

A silicon photodiode array with 50 dB dynamic range has been developed for integrated optical spectrum analyzer systems. The device consists of 140 pixels on a 12 micrometer pitch. Each pixel can be addressed within a period of 2μseconds. The device is butt coupled to an integrated optical waveauide spectrum analyzer circuit fabricated from lithium niobate.

Wideband Acousto-Optic Radiometry

The technique of acousto-optic spectrum analysis can be used to improve the signal to noise of r.f. signals by the noncoherent integration of photoelectrons in a properly configured optical sensor. The requirements placed upon the sensor and acousto-optic device to obtain a given processing gain, resolution, analysis bandwidth, and dynamic range are discussed for bulk optical devices.

High Speed Imager Preprocessor For Real-Time Acousto-Optic (AO) Spectrum Analyzer Systems

An advanced high speed imager preprocessor silicon micro electronic circuit for use with integrated and bulk real time A-0 spectrum analyzers is being developed. The circuits will be capable of analyzing and sorting by amplitude, frequency, and time of arrival, wide dynamic range optical signals presented at its focal plane.

WA-A2 High-speed Silicon CCD's fabricated on high-lifetime epitaxial material

For the fabrication of the BH laser, InGaAsP/InP doubleheterostructure layers were grown on a (1 00)-oriented n-InP substrate by LPE. Then a mesa stripe of an InGaAsP active region with a width of 2 pm was formed by perferential chemical etching. Side walls of the mesa were buried with p-InP and n-InP layers by the second LPE growth. The built-in reversebiased p-n junction effectively reduces leak current through the burying layers, especially at high temperatures. Finally, the wafer was cleaved and separated into 300-pm-long BH lasers. Low-threshold current of 22 mA under dc bias was achieved in this BH laser. This is the lowest value so far reported on the InGaAsP/InP BH laser’”. Stable fundamental transversemode operation without kinks in the light current characteristics were obtained up to more than 2 times threshold current. The frequency responce of the BH laser was very flat at least up to 1.3 GHz. The second-harmonic distortion of the BH laser output was 56 dB at a moduration index of 0.3, an output power 5 mW, and a modulation frequency 100 MHz.