Ii-vi Incorporated

Ii-vi Photonics, (us) Inc.

Photop Aegis, Inc.

Aegis Lightwave, Inc.

Michael Cahill

Christopher Stephen Koeppen

Jayesh C Jasapara

Glenn Bartolini

Rong Sun

John Dietz

An integrated optical tap monitor takes the form of a highly-reflective outer coating disposed over the active region of an associated photodetector. The coating is of a material that allows for a majority of the impinging optical signal to be re-directed into an output path, while passing a small portion of the signal into the photodetector's active region for monitoring purposes. The integrated configuration is small enough to be housed within a standard TO can, and additional optical components (filters, attenuators, etc.) may be co-located with the integrated tap monitor. By virtue of incorporating the monitoring function with a reflective surface, the integrated tap monitor may be substituted for a turning mirror at any place along a signal path and provide the benefit of power monitoring while also performing signal re-direction.

Integrated optical tap monitor

A multiport optical switch is used to controllably select a specific incoming optical signal that is to be processed by an associated optical channel monitor (OCM). The OCM includes a tunable optical filter and photodetector arrangement, and is configured to measure the optical spectrum of the incoming optical signal and extract information associated with the various optical channels forming the incoming optical signal (i.e., power, wavelength, OSNR, etc., per channel in the signal). The OCM also includes a processor that generates a pair of output control signals, a first signal to control the wavelength scanning process of the tunable optical filter and a second signal to control the setting of the multiport optical switch. The second signal may also be used to perform 'detuning' of a selected input of the multiport optical switch, providing the ability to adjust the power level of an input signal prior to entering the OCM.

Optical channel monitor with integral optical switch

A multiport optical switch (such as an N&#xd7;1 switch) is used to controllably select a specific incoming optical signal that is to be processed by an associated optical channel monitor (OCM). The OCM includes a tunable optical filter and photodetector arrangement, and is configured to measure the optical spectrum of the incoming optical signal and extract information associated with the various optical channels (wavelengths) forming the incoming optical signal (i.e., power, wavelength, OSNR and the like for each channel). The OCM also includes a signal processing component that generates a pair of output control signals, a first signal to control the wavelength scanning process of the tunable optical filter and a second signal to control the setting of the multiport optical switch.

A method of monitoring optical power in an optical channel includes directing a portion of a broadband optical signal propagating through an optical channel to an optical input of an electrically controllable tunable optical filter. The portion of the broadband optical signal is filtered with the electrically controllable tunable filter to select an optical channel for optical power monitoring. The selected optical channel is detected and an electrical signal that represents the selected optical channel is generated. An optical power of the selected optical channel is estimated from the electrical signal that represents the selected optical channel by performing an iterative deconvolution of the selected optical channel signal with a predetermined response function of the electrically controllable tunable optical filter.

Method and apparatus for estimating optical power

An optical receiver includes an optical detector that generates a photocurrent at an output. A transimpedance amplifier generates an amplified voltage signal corresponding to the photocurrent generated by the optical detector. An offset voltage generator generates an offset voltage that biases the voltage signal generated by the transimpedance amplifier. A switch having a first input electrically connected to the output of the transimpedance amplifier and a second input electrically connected to the output of the offset voltage generator switches between the offset voltage and the voltage signal generated by the transimpedance amplifier.

Optical receiver using single ended voltage offset measurement

A tunable laser includes an optical cavity comprising a first and second mirror. A gain medium is positioned in the optical cavity that generates stimulated emission in the optical cavity when biased. A thermally tunable optical filter is positioned in the optical cavity that is heated to a temperature that selects a desired optical mode of the optical cavity. A thermally tunable optical phase retarder is positioned in the optical cavity that is heated to a temperature which changes an optical path length in the optical cavity by an amount corresponding to a resonant frequency of the tunable optical filter so that a phase-matching condition of the optical cavity is shifted to the desired optical mode of the optical cavity selected by the thermally tunable optical filter.

Tunable Laser

An optical signal-to-noise ratio monitor includes a demodulator comprising an input that receives at least a portion of a phase modulated optical signal. The monitor also includes a delay interferometer with a periodic phase control that sweeps a differential delay of one arm of the interferometer through a plurality of differential optical phase shifts. The demodulator converts phase modulated optical signals to intensity modulated optical signals. A tunable optical filter continuously scans a transmission wavelength over a desired wavelength range in a time that allows more than one wavelength to be transmitted through an output of the tunable filter for each of the plurality of differential optical phase shifts. An optical detector detects the filtered optical signal and generates a corresponding electrical demodulation signal at an output. A processor determines an optical signal-to-noise ratio for the more than one wavelength of the optical signal.

Method and apparatus for in-band OSNR monitoring

A method for estimating optical power in an optical channel includes determining a tunable filter full-width, FW, by measuring a response of the tunable filter to a known signal and mapping the response to frequency. A portion of an optical channel is coupled to an input of the tunable optical filter. A peak power response, P, and a full width tunable filter response, FW, to the optical channel are determined by measuring a response of the tunable filter to the optical channel and mapping the response to frequency. A signal power, P, is then calculated from the peak power response, P, and a ratio of the full width tunable filter response, FW, to the tunable filter full-width, FW.

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Dedham, MA, United States of America

Michael Cahill