359 research outputs found
Compact silicon multimode waveguide spectrometer with enhanced bandwidth
Compact, broadband, and high-resolution spectrometers are appealing for sensing applications, but difficult to fabricate. Here we show using calibration data a spectrometer based on a multimode waveguide with 2 GHz resolution, 250 GHz bandwidth, and a 1.6 mm × 2.1 mm footprint. Typically, such spectrometers have a bandwidth limited by the number of modes supported by the waveguide. In this case, an on-chip mode-exciting element is used to repeatably excite distinct collections of waveguide modes. This increases the number of independent spectral channels from the number of modes to this number squared, resulting in an extension of the usable range
Optical Frequency Comb Noise Characterization Using Machine Learning
A novel tool, based on Bayesian filtering framework and expectation
maximization algorithm, is numerically and experimentally demonstrated for
accurate frequency comb noise characterization. The tool is statistically
optimum in a mean-square-error-sense, works at wide range of SNRs and offers
more accurate noise estimation compared to conventional methods
An ultra-fast method for gain and noise prediction of Raman amplifiers
A machine learning method for prediction of Raman gain and noise spectra is
presented: it guarantees high-accuracy (RMSE < 0.4 dB) and low computational
complexity making it suitable for real-time implementation in future optical
networks controllers
Deep Learning of Geometric Constellation Shaping including Fiber Nonlinearities
A new geometric shaping method is proposed, leveraging unsupervised machine
learning to optimize the constellation design. The learned constellation
mitigates nonlinear effects with gains up to 0.13 bit/4D when trained with a
simplified fiber channel model.Comment: 3 pages, 6 figures, submitted to ECOC 201
Phase Noise Compensation for Nonlinearity-Tolerant Digital Subcarrier Systems With High-Order QAM
The fundamental penalty of subcarrier modulation (SCM) with independent subcarrier phase noise processing is estimated. It is shown that the fundamental signal-to-noise ratio (SNR) penalty related to poorer phase noise tolerance of decreased baudrate subcarriers increases significantly with modulation format size and can potentially exceed the gains of the nonlinear tolerance of SCM. A low-complexity algorithm is proposed for joint subcarrier phase noise processing, which is scalable in the number of subcarriers and recovers almost entirely the fundamental SNR penalty with respect to single-carrier systems operating at the same net data-rate. The proposed algorithm enables high-order modulation formats with high count of subcarriers to be safely employed for nonlinearity mitigation in optical communication systems
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