Optimised design of ECL gates with power constraint

A design strategy for the optimisation of the propagation delay of low-power emitter coupled logic gates is discussed. These results can be applied when there is a power constraint and the level of available current is lower than the optimum. The strategy is independent of the process used and simple to design, avoiding the trial-and-error approach based on simulations. The use of the procedure is illustrated and validated by SPICE simulations on a two input multiplexer, using a bipolar process the npn transistor of which has an f/sub T/ of 20 GHz.     

Improved Reversed Nested Miller Frequency Compensation Technique With Voltage Buffer and Resistor

This brief introduces and develops a novel frequency compensation technique for three-stage operational transconductance amplifiers. The new compensation topology exploits a voltage buffer and a nulling resistor to achieve a double pole-zero cancellation, occurring beyond the gain-bandwidth product. To verify the effectiveness of the compensation scheme, an amplifier has been fabricated in a standard 0.5-mum CMOS process. Experimental measurements are found to be in good agreement with the theoretical analysis and show an improvement in small-signal and large-signal performances     

Direct Modulation Characteristics of Composite Resonator Vertical-Cavity Lasers

We report the small-signal modulation characteristics of a monolithic dual resonator vertical cavity surface emitting laser. The modulation response is described by a system of rate equations with two independent carrier populations and a single longitudinal optical mode. The independent optical overlaps and differential gains of the two active regions can each be adjusted to maximize the output response. We show that under certain conditions, the composite resonator may achieve a higher bandwidth than a single cavity laser with the same photon density. We find the relaxation oscillation frequency to depend mainly on the total photon density and not the individual currents in the two cavities. With appropriate current injection, the composite resonator laser achieves a maximum -3-dB bandwidth of 12.5 GHz and a maximum modulation current efficiency factor of approximately 5GHz/ma^1/2      

Dual-channel wavelength-division multiplexing using a composite resonator vertical-cavity laser

We demonstrate the use of a dual-resonator vertical-cavity laser diode as a coarse wavelength-division-multiplexing optical source. Binary data is encoded onto each of the two longitudinal modes, which can be independently modulated through current injection into each cavity. Using a single laser, we demonstrate data transmission on two independent channels.