We present a novel nonlinear transmission line (NLTL) pulse generator using dual-NLTL, true-time-delay, waveform-alignment technique, realized in Gallium Arsenide (GaAs) monolithic microwave integrated circuit (MMIC) technology. The diodes in these two NLTLs have opposite polarities in layout. Therefore, they are responsible for sharpening the two signals' rising and falling edges separately. A simple, low-cost, wideband combiner is adopted to combine the two fine aligned waveforms without introducing much distortion to the wideband signal. As a result, a sharp pulse is obtained with both edges compressed. With a sinusoidal signal as the input to the fabricated MMIC, a fall time of around 12 ps and rise time of 14 ps were measured at the output. This MMIC is a candidate for pulse or comb generators in many commercial and military applications.

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Abstract-We demonstrate for the first time an electroabsorption (EA) waveguide utilized as an integrated photodetector/mixer for frequency conversion of radio frequency signals, through field-controlled absorption. Using an InAsP-GaInP multiple-quantum-well EA waveguide, a conversion loss of 18.9 dB was obtained at 10-mW optical local oscillator (LO) power, and a suboctave, two-tone spur-free dynamic range of 120.0 dB-Hz 4 5 was measured for an up-converted signal at 1.9 GHz. This scheme can be useful in antenna applications where optical LO signal distribution is used for frequency converting microwave signals.Index Terms-Electroabsorption, frequency conversion, optoelectronic mixer, radio-frequency signal mixing, spur-free dynamic range.

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