Abstract: We disclose an optical transponder, in which one or more all-electronic feedback paths are used to obtain a relatively accurate estimate of the device-specific signal distortions in the transmitter portion thereof. The obtained estimate is used to enable the digital signal processor of the optical transponder to carry out electronic pre-distortion (EPD) that can significantly reduce or cancel these signal distortions without the use of detailed factory-calibration measurements or optics dedicated to feedback purposes. The use of all-electronic feedback paths may enable a beneficial reduction in the cost of the EPD functionality, e.g., by eliminating a significant extra cost associated with the implementation of optically generated feedback.

Abstract: We disclose an optical transponder, in which one or more all-electronic feedback paths are used to obtain a relatively accurate estimate of the device-specific signal distortions in the transmitter portion thereof. The obtained estimate is used to enable the digital signal processor of the optical transponder to carry out electronic pre-distortion (EPD) that can significantly reduce or cancel these signal distortions without the use of detailed factory-calibration measurements or optics dedicated to feedback purposes. The use of all-electronic feedback paths may enable a beneficial reduction in the cost of the EPD functionality, e.g., by eliminating a significant extra cost associated with the implementation of optically generated feedback.

Abstract: A novel 100+ Gbit/s opto-electronic receiver uses hybrid integration of a photodiode and a demultiplexer. The photodiode converts a high speed optical data stream to an electrical data stream that is input to an electronic demultiplexer. The photodiode and the demultiplexer are connected together by a novel planar microwave transmission structure.

Abstract: Duobinary and NRZ modulation of an X-Gb/s optical signal is achieved with a lumped element InP Mach-Zehnder device configured to operate at X/k-Gb/s where k>1 and arranged in a push-pull configuration.

Abstract: A novel 100+ Gbit/s opto-electronic receiver uses hybrid integration of a photodiode and a demultiplexer. The photodiode converts a high speed optical data stream to an electrical data stream that is input to an electronic demultiplexer. The photodiode and the demultiplexer are connected together by a novel planar microwave transmission structure.

Abstract: Duobinary and NRZ modulation of an X-Gb/s optical signal is achieved with a lumped element InP Mach-Zehnder device configured to operate at X/k-Gb/s where k>1 and arranged in a push-pull configuration.

Abstract: A (binary) signal is transmitted through an electrical backplane, and the received signal is interpreted as a duobinary signal. In order to ensure that the received signal can be properly interpreted as a duobinary signal, the data signal is preferably filtered prior to being interpreted. The filter is preferably designed such that the combination of filter and the backplane approximates a binary-to-duobinary converter. In one embodiment, an (FIR-based) equalizing filter is applied to the data signal prior to transmission to emphasize the high-frequency components and flatten the group delay of the backplane. The resulting, received duobinary signal is converted into a binary signal by (1) splitting the duobinary signal, (2) applying each copy to a suitably thresholded comparator, and (3) applying the comparator outputs to a suitable (e.g., XOR) logic gate. The transmission system enables high-speed data (e.g., greater than 10 Gb/s) to be transmitted over relatively inexpensive electrical backplanes.

Abstract: In one embodiment, a duobinary-to-binary signal converter includes a pair of comparators coupled to a logic gate. Each comparator receives a copy of a duobinary-encoded analog signal applied to the converter and is designed to generate a binary output based on the comparison of the magnitude of the received signal with a corresponding threshold voltage. The outputs of the comparators are fed into the logic gate, which generates a binary sequence corresponding to the duobinary-encoded signal. A representative converter of the invention can perform relatively well at bit rates as high as about 40 Gb/s and can be conveniently incorporated into an appropriate integrated device (e.g., an ASIC) for a data transmission system employing duobinary signaling.