Abstract: Disclosed herein are a system and method for three-dimensional imaging using a single transducer. A laser in a transmitter emits a sequence of short pulses, each of which is at a different center wavelength (frequency). A dispersive element in the transmitter spatially separates the pulses according to wavelength, with different pulses mapped to different spatial locations in a target volume via a lens. The pulses travel to the target, which scatters or back-reflects the pulses towards the dispersive element via the lens. The lens collects the returned pulses and transmits them to a single transducer via the dispersive element. The transducer measures the time of arrival for each returned pulse. Because the arrival time depends on the range to the object in the portion of the target illuminated by the corresponding emitted pulse, the measured arrival time can be used to reconstruct a 3D (angle-angle-range) image of the object.

Abstract: Described are an FSK modulator and a method for large-alphabet FSK modulation. The FSK modulator and the method are based on filtering of a multi-tone optical source such as a mode-locked laser which provides a comb distribution of tones. A frequency-selective component selects for transmission a subset of the tones. In various embodiments the frequency-selective component is a Mach-Zehnder interferometer filter or a microring resonator filter. A second frequency-selective component selects a subset of the tones from the comb distribution provided by the first frequency-selective component. Still more frequency-selective components can be used according to the number of tones supplied by the multi-tone optical source to the FSK modulator. The optical signal exiting the last frequency-selective component includes only a single tone which corresponds to the symbol to be transmitted.

Abstract: A variable-bit-rate communication system is described. The communication system includes a variable-bit-rate transmitter that generates digital data at a first or a second bit rate and a variable-bit-rate receiver that receives the digital data. The digital data comprises a sequence of signaling waveforms having a first or a second duty cycle, respectively, wherein each signaling waveform has the same shape.

Abstract: An optical modulator includes an optical pulse train generator that forms an optical pulse train of a predetermined frequency at a generator output. The optical modulator also includes an optical pulse train modifier having a first input optically coupled to the output of the pulse train generator, a second input, and an optical output. The modifier produces a modulated optical pulse train related to a signal appearing at the second input and having an optical sub-carrier frequency related to the predetermined frequency of the optical pulse train at the first input.