To provide a means which enables wavelength conversion and regeneration of an input optical signal.

A source (2) is provided which is on/off switchable of a continuous optical signal at a respective wavelength (λ2). A Michelson interferometer (10) is provided which is adapted to receive an input signal(IS) and the continuous optical signal generated by the source (2) to generate an output signal(OS). When a wavelength (λ1) of the input signal(IS) corresponds to the wavelength (λ2) of the source, the source (2) is switched off and the output signal(OS) is a replica of the input signal(IS) regenerated at the interferometer (10). When the wavelength (λ1) of the input signal(IS) is different from the wavelength (λ2) of the source, the source (2) is switched on and the output signal(OS) is a replica of the input signal(IS) regenerated at the interferometer (10), and the wavelength is converted to the wavelength (λ2) of the source.