Exfo Inc.

Picosolve Inc.

Peter Andrekson

Mathias Westlund

Henrik Sunnerud

Mats Skold

Bengt-Erik Olsson

Bernard Ruchet

Mats Sköld

A two-gate sampling system has been designed to perform sampled balanced detection of one or more input signal pairs. The present invention performs simultaneous sampling of both signals in each signal pair followed by digitization and combination of the sample pairs using software. By first sampling the signals and then combining the sampled into the corresponding balanced detected signal it is possible to avoid the bandwidth limitations and impedance problems introduced by traditional balanced detectors and electrical oscilloscopes. In particular, for optical sampling gates very high bandwidth sampling gates can be designed without any impedance issues and hence almost perfect balanced detection reconstruction can be performed for very high speed signals. Balanced detection is becoming more and more important as the new phase modulated optical data signals are introduced to the market, such as e.g. PSK, DPSK, QPSK and DQPSK. The present invention is well suited for analysis of these new types of signals.

Sampling-based balanced detection system

An optical sampling arrangement for high-speed measurement of the time-varying electric field of an optical input signal utilizes coherent mixing of the optical input signal with a reference laser source in a phase-diverse optical hybrid solution, followed by optical sampling of the coherently-mixed fields at the output of the optical hybrid. The generated streams of optical samples are then detected and signal processed in order to reconstruct a sampled version of the electric field of the original optical input signal.

All-optical, phase sensitive optical signal sampling

An optical sampling arrangement for high-speed measurement of the time-varying electric field of a data-carrying optical input signal. The present invention includes optical sampling of the optical input signal, followed by coherent mixing with a reference laser source in an optical hybrid solution. The generated streams of mixed optical samples are then detected and signal processed in order to reconstruct a sampled version of the electric field of the data-carrying optical input signal.

Optical sampling with coherent detection

An asynchronous sampling arrangement utilizes sampling of both a high speed data signal and a trigger (clock) signal. The data signal may be either an optical signal or an electrical signal. The data and trigger signals are sampled in parallel by two separate gates, the gates based on the same strobe frequency. The samples corresponding to the trigger signal are then processed through an algorithm that determines the time-base related to the sampled signal. This established time-base is then used to reconstruct the sampled version of the high data rate input signal waveform.

Equivalent time asynchronous sampling arrangement

A system and method for providing polarization-independent optical sampling utilizes a differential group delay (DGD) element to split a sampling pulse source (SPS) into orthogonal components by controlling the state of polarization of the SPS at the DGD element input. The orthogonally-polarized sampling pulse components then each interact with the input optical signal waveform in a polarization-dependent sampling gate, creating two samples for each original sampling pulse. The generated samples are converted into the electrical domain by a photodetector with an impulse response time longer than that associated with the DGD element, resulting in a single impulse response representing the combined energy of the two samples that is independent of the state of polarization of the input optical signal waveform.

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Fogelsville, PA, United States of America

Peter Andrekson