An Undersea Fiber-Optic Regenerator Using an Integral-Substrate Package and Flip-Chip SAW Mounting

A 324-Mbit/s electrical regenerator module intended for undersea optical-fiber systems is described. It has a sensitivity of 20 mV peak to peak, at which the total jitter is 3.3° rms, a low figure achieved by close attention to balance at chip and circuit board level. Timing phase adjustment is by means of a single select-on-test resistor, which enables the timing to be optimized quicker and more accurately than by conventional means. The regenerator functions are realized using four chips in the proven ECL-40 technology. This number reduces to three if a 28-pin chip carrier is used. The power consumption of these chips totals 1.3 W. The module incorporates a novel method ("flip-chip") of mounting SAW filters which is mechanically robust without the use of organic compounds, and which improves SAW performance by the virtual elimination of electromagnetic breakthrough.