Peter S. Cross

Optically controlled two channel integrated-optical switch

An integrated optical bistable device based on a waveguide directional coupler switch is demonstrated. The device has four optical ports, and the power incident on the two input ports exists from two distinct output ports so that all-optical data processing or remote optical switching can be performed. On/off ratios as high as 12 dB have been observed. A switching time of \sim300 \mu s and switching energy of ∼3 pJ have been achieved.

Microwave integrated optical modulator

A Ti‐diffused lithium niobate, traveling wave modulator has been fabricated and tested at microwave frequencies. A Mach–Zehnder interferometer optical configuration and a coplanar waveguide electrical transmission line are used. For a 4‐mm interaction length, the modulator has a 3‐dB bandwidth of 13 GHz and requires only 2 V to switch at λ=840 nm. The frequency response is measured directly using an ultrahigh speed photodiode, and the test setup therefore constitutes the highest bandwidth efficient electro‐optical transmission system ever reported.

Surface transverse wave resonator

A surface transverse wave resonator comprises a piezoelectric substrate having at least one surface, wherein said substrate includes a crystalline structure that permits the propagation of transverse waves. The resonator also comprises a transducing set of periodic perturbations which are positioned atop the substrate surface, wherein the transducing set converts electromagnetic energy from an external source into the transverse waves. The resonator further comprises a receiving set of periodic perturbations which are positioned atop the substrate surface remote of the transducing set of periodic perturbations, wherein the receiving set converts the transverse waves into resultant electromagnetic energy. Moreover, the resonator includes a central set of surface-trapping periodic perturbations for maintaining the transverse waves adjacent to the substrate surface, wherein the central set is positioned intermediate the transducing set and the receiving set. Further, the resonator includes at least two sets of reflecting periodic perturbations for reflecting the transverse waves, wherein each of the sets of reflecting periodic perturbations is positioned adjacent to a respective one of the transducing set and the receiving set remote of the central set.

A 1 Gbit/s integrated optical modulator

A waveguide directional coupler modulator is demonstrated with a bandwidth of 1 GHz and a rise time of 590 ps. An analysis of the electrical parasitics is presented and the device response is found to be transit-time limited. The scaling of the frequency response is shown to be characterized by a bandwidth-length product of 1.1 GHz - cm.

Picosecond Optical Electronic Measurements

We report the development of an electro-optic sampling system and its application to the characterization of high speed GaAs Schottky photodiodes. This system achieves a temporal resolution of 2 ps and shot noise limited sensitivity of 11 μV√Hz.

A Traveling Wave, Microwave Optical Modulator

A Ti-diffused lithium niobate, traveling wave modulator has been fabricated and tested. A Mach-Zehnder interferometer optical configuration and a coplanar waveguide electrical transmission line are used. For a 4mm interaction length, the modulator has a 3dB bandwidth of 13 GHz and requires only 2 volts to switch at λ = 840 nm. The frequency response is measured directly using an ultra-high speed photodiode, and the test set-up therefore constitutes the highest bandwidth electrooptical transmission system ever reported.