Tunable optical filter tuning device suitable for use in the receive part of an optical transmission system
AssigneeAlcatel Cit
InventorsOlivier Gautheron, Christian Coeurjolly
Life of this patent
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Abstract
A tunable optical filter tuning device suitable for use in the receive part of an optical transmission system rejects some of the optical noise superimposed on a wanted optical signal. The device commands displacement of the characteristic of the optical filter along the wavelength axis and includes a tuning detector to detect the time at which this displacement can be stopped. The tuning detector includes an optical power detector receiving a signal from the optical filter and detects any modulation of a signal from the optical power detector. The displacement is stopped when the detector detects modulation of the signal from the optical power detector.
Claims7
A tunable bandpass optical filter tuning device suitable for use in the receive part of an optical transmission system for transmitting an information signal containing a spectrum of frequencies, and adapted to reject some optical noise superimposed on a wanted optical signal, said device including means for commanding displacement of the passband of said optical filter along a wavelength range, and tuning detector means adapted to detect the time at which said displacement can be stopped, said tuning detector means including an optical power detector receiving an optical signal from said optical filter, and modulation detector means for detecting any modulation of an electric signal from said optical power detector with the exception of a null frequency of said electric signal, said, displacement being stopped when said modulation detector means detects modulation of said electric signal from said optical power detector;
- wherein, said optical noise comprising noise created by a receive optical preamplifier, said modulation detector means comprises;
- measuring means for measuring a magnitude characteristic of the amplitude of said electric signal from said optical power detector other than its mean value, said measuring means having a bandwidth excluding said null frequency and including some or all of the frequencies forming the spectrum of the information signal conveying information to be transmitted by the system;
- and
- means for comparing a result supplied by said measuring means to threshold so that, according to whether the optical signal received by said optical power detector is entirely constituted of said optical noise or not, the result supplied by said measuring means is differently situated relative to said threshold,
A tunable bandpass optical filter tuning device suitable for use in the receive part of an optical transmission system for transmitting an information signal containing a spectrum of frequencies, and adapted to reject some optical noise superimposed on a wanted optical signal, said device including means for commanding displacement of the passband of said optical filter along a wavelength range, and tuning detector means adapted to detect the time at which said displacement can be stopped, said tuning detector means including an optical power detector receiving an optical signal from said optical filter and modulation detector means for detecting any modulation of an electric signal from said optical power detector with the exception of a null frequency of said electric signal, said displacement being stopped when said modulation detector means detects modulation of said electric signal from said optical power detector;
- wherein a pilot carrier signal frequency is not transmitted with the information signal for tuning said filter.
Dependencies are inferred from the claim text.