Bit error rate measurements were performed on a 50 Gbit/s optical time domain multiplexed system which utilized the newly developed Terahertz Optical Asymmetric Demultiplexer (TOAD) device as the front end of a receiver. Bit error rates of less than 10-9 were measured when 800 fj control pulses were used to gate the demultiplexer. These measurements, which were made on a 50 Gbit/s peak line-rate train, also quantified the tolerance of the TOAD to signal-control pulse jitter

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Far-field radiation pattern measurements have been used to evaluate the modal structure and dispersion associated with 0.85-pm wavelength light launched from high-brightness light emitting diodes (LED's) into TIA Class IVa fiber. The measured far-field radiation pattern of the light intensity emitted from the end of the optical fiber is compared to the far-field radiation pattern calculated from the Fraunhofer approximation to the diffraction integral with the result that two linearly polarized (LP) modes propagate in the optical fiber and that the optical power is nearly equally distributed between the two modes. The modal dispersion associated with the use of a 0.85-pm wavelength emitter and a TIA Class IVa fiber is evaluated to be 2.3 ns/km, which is adequate for a variety of local-area networks and point-to-point optical communications links.

A high contrast, low intensity GaAlInAs/AlInAs multiple quantum well asymmetric Fabry–Perot reflection modulator for operation at 1.3 μm has been demonstrated. The reflection modulator takes advantage of the large absorptive and refractive nonlinearities associated with saturating the heavy-hole exciton resonance. We achieve an on/off contrast ratio in excess of 1000:1 (30 dB) and an insertion loss of 2.2 dB at a pump intensity of 30 kW/cm2, corresponding to a carrier density of 4.5×1017 cm−3. The modulator was demonstrated to have a large operating bandwidth, achieving an on/off contrast ratio of greater than 100:1 over a 5 nm optical band. The operating speed of the modulator was measured and found to approach 1 GHz.

A new type of ultrafast all optical switch based on a Mach–Zehnder interferometer is demonstrated with a 10 ps switching window which requires only 0.65 pJ of control pulse energy. The optical nonlinearity which is utilized is associated with the gain compression of semiconductor optical amplifiers, and the switching turnoff transition does not depend on the slow amplifier recovery time. Both data and control pulses are at the same wavelength of 1.313 μm, and are not polarized orthogonal to each other. The device configuration and the semiconductor amplifiers allow for small scale integration and data output cascadability.