In this work a narrow linewidth (1 kHz) laser source is used to measure the free spectral range of a fiberized Fabry-Perot etalon with sub-Hz accuracy (10(-8)). A previously demonstrated technique based on the Pound-Drever-Hall error signal is improved in accuracy by the use of a narrow linewidth laser swept in frequency via an acousto-optic modulator, or single sideband generation. The sub-Hz (10(-8)) accuracy attained enables the characterization of both the long-term drift and the polarization dependence of the free spectral range of the fiberized etalon.

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A 100,000 finesse Fabry-Perot etalon with a 1.5 GHz free spectral range is used as a photonic filter in an optoelectorinc oscillator. The etalon acts as a ~15 kHz microwave filter to suppress spurious modes in a single loop OEO configuration. The etalon maintains its narrow filtering capability at harmonics of the FSR. Phase noise of the 10.5 GHz tone with 2 km of delay is measured at -120 dBc/Hz at 10 kHz offset. Oscillation as high as 54 GHz with 3 km of fiber delay is achieved while maintaining suppression of spurious modes below the noise floor of the measurement. Pound-Drever-Hall frequency stabilization of the laser frequency is used to reduce optical frequency noise and keep the laser frequency centered within the etalon resonance for long term operation of the OEO.

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Group delay and higher order dispersion measurements are conducted on a 1.3 μm quantum dot semiconductor optical amplifier at various injection currents. White-light spectral interferometry is performed, along with a wavelet transform to recover the group delay. The group delay, group velocity dispersion, and higher order dispersion terms are quantified. The measurement spans both ground state and first excited state transitions, ranging from 1200 to 1320 nm. The group velocity dispersion, β2, is found to be −6.3×103 fs2 (7.6 fs/nm) at an injection current of 500 mA.