SEVEN-TIMES RESOLUTION IMPROVEMENT IN NARROWBAND POLARIZATION-MODE DISPERSION.
Now, NIST has assembled a second-generation MPS system that has demonstrated a PMD resolution of about 20 fs in a bandwidth of 5 GHz, an approximate sevenfold improvement over the previous MPS system. We are not aware of any other MPS system with such high PMD resolution. The system is based an RF comb-generator that modulates laser light at 2.46 GHz and mixes the detected power to a 123 MHz frequency measurable by a low-phase-noise RF lock-in amplifier. The PMD resolution of the system appears to be limited by the phase noise of the lock-in amplifier itself. We have also found the technique to be surprisingly susceptible to optical reflections in the component under test. Future work will be done toward reducing optical reflections and their effects.
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|Publication:||Journal of Research of the National Institute of Standards and Technology|
|Article Type:||Brief Article|
|Date:||Jul 1, 2001|
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