Ultrafast all-optical switching utilizing the optical Kerr effect in polarization-maintaining single-mode fibers

An ultrafast all-optical switching scheme utilizing the optical Kerr effect in two birefringent fibers concatenated with each fast axis crossed is proposed. Stable optical Kerr modulation and all-optical demultiplexing of an ultrashort (30 p.s.) optical pulse train at 1.97 GHz from a gain-switched distributed-feedback laser diode (DFB LD) have been sufficiently demonstrated using CW mode-locking Nd:YAG laser pulses as a pump. Switching speed and required pump powers are studied in terms of fiber bandwidth due to fiber birefringence, and combined effects of chromatic and polarization dispersions on Kerr modulation profiles. By utilizing the optical Kerr modulation properties in the presence of dispersions, the nondiagonal yx component of the nonlinear refractive index is also determined to be 0.34 relative to the diagonal component xx. The intrinsic stability and ultimate switching capabilities are discussed.< >