2R Regenerator Design
The schematic of the conventional Mamyshev regenerator is shown above. A High-Power Erbium doped fiber amplifier (HP-EDFA) boosts the incoming signal to the power (Pm) required for optimal peak power equalization of the ‘one’ symbols. This amplifier can be followed by an optical bandpass filter (not shown in the figure) in order to reject out of band amplified spontaneous emission.
The self-phase modulation-induced spectral broadening is generated in a single-mode optical fiber with a length . The chromatic dispersion of this fiber is normal and its value is D. The nonlinear coefficient is, and the linear losses are . Several types of fibers have been successfully tested : non-zero dispersion-shifted fibers, highly nonlinear silica fibers (HNLF), microstructured silica fibers, chalcogenide fibers or tellurite fibers.
At the fiber output, an optical bandpass filter (OBPF) with a FWHM spectral width, (defined such that the pulse width at the output is the same as that at the input of the system), is spectrally offset by an amount with respect to the input signal carrier wavelength and is used to carve into the broadened spectrum - thereby acting as a pulse reshaper.
This is the unit configuration, which may be repeated for higher accuracy of the regeneration.
Note that it has been shown possible to advantageously replace the nonlinear fiber by a highly-nonlinear chalcogenide waveguide, therefore opening the way to all-integrated photonic chip regeneration.
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“Delay always breeds danger; and to protract a great design is often to ruin it.”
—Miguel De Cervantes (15471616)