Improvement of wavelength detuning tolerance in non-return-to-zero to return-to-zero signal conversion using null-expanded phase shifted fiber Bragg gratings

Improvement of wavelength detuning tolerance in the non-return-to-zero to pseudo-return-to- zero signal conversion for clock signal extraction, using null-expanded phase-shifted fiber Bragg gratings (NE-PSFBGs), has been experimentally demonstrated. With the NE-PSFBG having more than five times wider nulls than the conventional PSFBG, the wavelength detuning tolerance was improved 40 %.