Y. Silberberg

Observation of spatial optical solitons in a nonlinear glass waveguide

We report the observation of spatial optical solitons due to the Kerr nonlinearity in a planar glass waveguide and present measurements of the nonlinear response obtained by placing a pinhole at the output of the waveguide. For input intensities greater than that required for the fundamental soliton, we observe breakup of the output owing to the effect of two-photon absorption.

Femotosecond switching in a dual-core-fiber nonlinear coupler

We report all-optical switching of 100-fsec pulses in a fused-quartz dual-core-fiber directional coupler. The length of the device is 0.5 cm, and the switching power is 32 kW. Pulses are routed to either of two separate fiber guides, depending on the input power. Measurements of pulse reshaping by the nonlinear coupler provide compelling evidence of the devices ability to response on a femotosecond time scale.

Digital optical switch

We propose and demonstrate a novel polarization‐ and wavelength‐independent digital electro‐optic switch in Ti:LiNbO3. This four‐port integrated optics switch is characterized by a steplike response to the applied voltage. Switching is achieved through adiabatic eigenmode transformation in an asymmetric waveguide junction. We demonstrate switching of both polarization components at two wavelengths (1.32 and 1.52 μm) with a crosstalk of −20 dB.

Ultrafast all‐optical switching in a dual‐core fiber nonlinear coupler

We report the first demonstration of a nonlinear coupler switch capable of substantially complete all‐optical switching at subpicosecond rates with no light‐induced thermal effects.

Passive mode locking of a semiconductor diode laser

By using a GaAs/GaAIAs multiple-quantum-well sample as a saturable absorber in an external resonator, we have passively mode locked a GaAs laser to obtain pulses as short as 1.6 psec, the shortest pulses ever observed to our knowledge from a mode-locked diode laser in a regulator pulse train.

Experimental observation of spatial soliton interactions

We report the experimental observation of interaction forces between two fundamental spatial optical solitons in a nonlinear glass waveguide. Both attraction and repulsion were observed, depending on the relative phase between the solitons.

Spatial optical solitons in planar glass waveguides

We report experimental studies of spatial optical solitons in a nonlinear glass waveguide. Spatial solitons are self-trapped beams that propagate without diffraction. We demonstrate the formation of spatial solitons, and we investigate interactions between them. At high intensities two-photon absorption is observed to lead to the breakup of solitons. A beam propagation method is used to simulate the experimental conditions numerically, and the results agree well with experiment.

Nonlinear coupling of waveguide modes

We show that the nonlinear coupling between two waveguide modes can lead to both power exchange and nonlinear phase shifting between the modes. New applications of nonlinear phase shifting to all‐optical devices are described.

Passive mode locking by using nonlinear polarization evolution in a polarization-maintaining erbium-doped fiber

By using a new simple cavity design, in which both linear and nonlinear polarization evolution are reproducibly controlled, we demonstrate passive mode locking in a Fabry–Perot-type erbium fiber laser. The laser generates stable trains of pulses as short as 200 fs with an energy content of 70 pJ at repetition rates as high as 100 MHz.

Mode locking of semiconductor diode lasers using saturable excitonic nonlinearities

Multiple-quantum-well (MQW) structures of GaAs and GaAlAs have been used for passive mode locking of commercial GaAs semiconductor diode lasers. We present an extended discussion of this application of the sensitive room-temperature excitonic absorption saturation in MQW material. We review the criteria for passive mode locking and discuss two methods—carrier diffusion and proton bombardment—for reducing the aborption recovery time without destroying the excitonic nonlinearity. A simple probabilistic theory is derived for the effect of bombardment on the excitonic effects that is in order-of-magnitude agreement with experiment. We have performed experiments using MQW material to mode lock a GaAs laser. A continuous train of pulses as narrow as 1.6 psec has been obtained with a pulse-repetition rate of 2 GHz.