Simultaneous amplitude and phase measurement for periodic optical signals using time-resolved optical filtering

Abstract

Abstract:Time-resolved optical filtering (TROF) measures the spectrogram or sonogram by a fast photodiode followed a tunable narrowband optical filter. For periodic signal and to match the sonogram, numerical TROF algorithm is used to find the original complex electric field or equivalently both the amplitude and phase. For phase-modulated optical signals, the TROF algorithm is initiated using the craters and ridges of the sonogram.

Phase and Amplitude Responses of Narrowband Optical Filter Measured by Microwave Network Analyzer

“…• phase change in the important region of ±7.5 GHz, confirming the assumption of [5], [6] that the monochromator does not have dispersion.…”

“…Recently, narrow-band optical filter was used for timeresolved optical filtering (TROF) to simultaneously measure the amplitude and phase of an optical signal with [5] or without chromatic dispersion [6]. The dual of frequencyresolved optical gating (FROG) [7], TROF needs an accurate tunable narrow-band optical filter to obtain the spectrogram.…”

“…The dual of frequencyresolved optical gating (FROG) [7], TROF needs an accurate tunable narrow-band optical filter to obtain the spectrogram. Ideally, the tunable optical filter of [8] in the measurement of [5], [6] does not have dispersion. An accurate measurement is required to confirm the dispersionless assumption in [5], [6], [8].…”

“…Ideally, the tunable optical filter of [8] in the measurement of [5], [6] does not have dispersion. An accurate measurement is required to confirm the dispersionless assumption in [5], [6], [8].…”

“…The responses of the optical filter are measured to the amplitude and frequency accuracy of the network analyzer. When the optical filter of [5], [6], [8] is measured, the frequency resolution is down to 25 MHz and the frequency accuracy or resolution bandwidth is down to 1 kHz. The measurement result is crucial for TROF to retrieve electric field of an optical signal.…”