Residual PM and AM noise measurements, noise figure and jitter calculations of 100 GHz amplifiers

We report the first definitive PM and AM noise measurements at 100 GHz of indium phosphide (InP) amplifiers operating at 5 K, 77 K, and room temperature. Amplifier gain ranged from +7 dB to +30 dB, depending on input RF power levels and operating bias current and gate voltages. The measurement system, calibration procedure, and amplifier configuration are described along with strategies for reducing the measurement system noise floor in order to accurately make these measurements. We compute amplifier noise figure with an ideal oscillator signal applied and, based on the PM noise measurements, obtain NF = 0.8 dB, or a noise temperature of 59 K. Measurement uncertainty is estimated at +/-0.3 dB. Results show that the use of the amplifier with an ideal 100 GHz reference oscillator would set a lower limit on rms clock jitter of 44.2 fs in a 20 ps sampling interval, if the power into the amplifier were -31.6 dBm. For comparison, clock jitter is 16 fs with a commercial room-temperature amplifier operating in saturation with an input power of -6.4 dBm.