Yutaka Fukuchi

Novel design method for all-optical ultrafast gate switches using cascaded second-order nonlinear effect in quasi-phase matched LiNbO 3 devices

The authors propose a novel method of designing all-optical ultrafast gate switches that employ the cascade of the second harmonic generation and difference frequency mixing in quasi-phase matched LiNbO/sub 3/ devices. In this design method, the device length is maximized under the condition that crosstalk of the switch is maintained below a certain allowable value at a given bit rate. Following the design method, the authors find that the switching efficiency can significantly be enhanced by compensation for the walkoff between the fundamental and second harmonic pulses.

Speed limit of all-optical gate switches using cascaded second-order nonlinear effect in quasi-phase-matched LiNbO 3 devices

In all-optical gate switches that employ the cascaded second-order nonlinear effect in quasi-phase-matched (QPM) LiNbO/sub 3/ devices, walkoff between the fundamental and second harmonic pulses is very large. The authors experimentally show that crosstalk of the switch induced by such walkoff limits the switching speed, but that the switching speed can significantly be enhanced by walkoff compensation. Using a 20-mm-long QPM LiNbO/sub 3/ waveguide device, the authors switch one of twin pulses separated by 6.25 ps without crosstalk, showing the possibility of switching a 160-Gb/s signal.

Characteristics of ultra-fast four-wave mixing switch using cascaded second-order nonlinearity in quasi-phase matched devices

Summary form only given. Quasi-phase matched (QPM) LiNbO/sub 3/ devices have recently realized efficient wavelength conversion and optical phase conjugation in the optical communication band at 1550 nm. In such devices, four-wave mixing (FWM) occurs through the cascaded /spl chi//sup (2)/ effect, and the phase matching wavelength for FWM can be controlled. We have performed numerical analysis of the ultra-fast FWM switch.

Characteristics of All-Optical Ultra-Fast Retiming Switches Using Cascade of Second Harmonic Generation and Difference Frequency Mixing in Periodically Poled Lithium Niobate Waveguides

We numerically calculate the performance of all-optical retiming switches employing the cascaded second-order nonlinear effect in quasi-phase-matched lithium niobate waveguides. A time offset between the signal and clock pulses can improve the timing-jitter transfer characteristics.

Analysis of amplitude squeezing of harmonic generation in a quasi-phase-matched device: effect of stochastic variation of domain length

Amplitude squeezing of the second-harmonic generation in periodically poled quasi-phase-matched devices is analyzed with consideration for errors of the domain length. We show that the amount of squeezing is a complex function of the phase mismatch and of the input power and that it is practically impossible to maintain the perfect quasi-phase matching for an arbitrary input power. For evaluation of the availability of squeezing, we propose a contour map of squeezing that can visualize the tolerance of squeezing for the phase mismatch. It is shown that the effect of domain length error depends on the type of the error; the random duty-cycle error, where the mean domain period is precisely fixed, does not alter the squeezing performance, whereas the random period error, which fluctuates during the domain period, severely alters tuning characteristics. The available amount of squeezing is predicted to be determined by the tuning stability of the device.

Characteristics of all-optical ultra-fast gate switches using the cascaded second-order nonlinear effect in quasi-phase matched lithium niobate devices

We numerically analyze switching characteristics of all-optical gate switches using the cascade of second harmonic generation and difference frequency mixing in quasi-phase matched Lithium Niobate devices, and show possibility of efficient ultra-fast operation beyond 1Tbps.

Broadband Wavelength-Tunable Actively Mode-Locked Fiber Ring Laser Using a Bismuth-Oxide-Based Erbium-Doped Fiber

We demonstrate an actively mode-locked fiber ring laser employing a 151-cm-long bismuth-oxide-based erbium-doped fiber. Stable short pulses at 10GHz are obtained with a broadband wavelength tuning range of 66nm covering both the C- and L-bands.