Symmetric Mach-Zehnder All-optical Switch Research Articles

Demultiplexing of 168-Gb/s data pulses with a hybrid-integrated symmetric Mach-Zehnder all-optical switch

We have developed a hybrid-integrated symmetric Mach-Zehnder all-optical switch and evaluated the demultiplexing of 168-Gb/s data pulses at a repetition rate of 10 GHz with this switch. A compact, stable device was realized by assembling semiconductor optical amplifiers as nonlinear waveguides on a planar lightwave circuit in a self-aligned manner. A 6.0-ps switching window needed for 168-Gb/s demultiplexing was provided by the push-pull operation of the symmetric Mach-Zehnder all-optical switch. Demultiplexed signal light showed a high extinction ratio of better than 18 dB. Error-free demultiplexing with a bit error rate of 10/sup -11/ was achieved.

Femtosecond Operation of Symmetric Mach-Zehnder All-Optical Switch and Its Photonic Integration.

Femtosecond Operation of Symmetric Mach-Zehnder All-Optical Switch and Its Photonic Integration.

Ultrafast (200-fs switching, 1.5-Tb/s demultiplexing) and high-repetition (10 GHz) operations of a polarization-discriminating symmetric Mach-Zehnder all-optical switch

We demonstrate 200-fs switching and 1.5-Tb/s demultiplexing with a polarization-discriminating, symmetric Mach-Zehnder (PD-SMZ) all-optical switch. This switch is based on a highly efficient but slowly relaxing band-filling effect resonantly excited in a passive InGaAsP bulk waveguide. By using a mechanism that cancels out the effect of the slow relaxation, ultrafast switching is realized. The applicability of this mechanism to optical demultiplexing of well over 1 Tb/s is experimentally demonstrated for the first time. High-repetition operation at 10 GHz with the same nonlinearity used for the present ultrafast switching is also verified.

Cross-correlation measurement of ultrafast switching in a symmetric Mach–Zehnder all-optical switch

We present cross-correlation measurement of ultrafast switching in a symmetric Mach–Zehnder all-optical switch. A full width at half-maximum of 2 ps has been achieved in the cross-correlation trace, corresponding to the estimated switching time of 1.5 ps. Both the switch-on and switch-off time of the measured traces are limited only by the control pulse duration of 1.1 ps. These results indicate that the effects of group velocity dispersion and intraband carrier relaxation are negligible within the present time scale.

Ultrafast All-Optical Switch with an Operational Speed Unlimited by the Slow Relaxation of a High Efficiency Nonlinear Refractive Index Change.

We experimentally demonstrate that the switching speed of a novel symmetric Mach-Zehnder (SMZ) all-optical switch, proposed by the present authors, is unrestricted by normally slow relaxation times of highly efficient, incoherent nonlinear refractions. A cross-correlation trace with a full-width at half-maximum of 2 ps was achieved, which is corresponding to nearly full-switching at 1.5 ps. To our best knowledge, this is the fastest switching experiment with incoherent and thus realistic nonlinearities. We also demonstrate that a repetition rate much faster than that implied by the relaxation time of the utilized optical nonlinearity is also possible with the SMZ all-optical switch. We will explain an experimental result under excitation by packets of four control pulses with a pulse interval of 100ps. We point out that the well-known figure of merit for optical nonlinear materials is no longer applicable to the present device and discuss how it is modified to take full advantage of the present device. We also note that a square-like, contrary to the exponential-like, switching characteristic is quite important in practice and show that such square-like modulation is possible with the SMZ all-optical switch.