Abstract: This disclosure describes techniques to sample electrical data streams in coherent receivers. For instance, an analog-to-digital converter (ADC) samples the received electrical data stream at a sampling rate that is nominally twice or greater than twice the symbol rate of the electrical data stream that the ADC receives. A digital filter receives the digital data stream from the ADC, and digitally filters the digital data streams to output a filtered digital electrical data stream at an effective sampling rate that is less than the sampling rate and less than twice the symbol rate, and greater than or equal to the symbol rate.

Abstract: In some embodiments, a system includes a set of servers, a set of switches within a switch fabric, and an optical device. The optical device is operatively coupled to the set of servers via a first set of optical fibers. Each server from the set of servers is associated with at least one wavelength from a set of wavelengths upon connection to the optical device. The optical device is operatively coupled to each switch from a set of switches via an optical fiber from a second set of optical fibers. The optical device, when operative, wavelength demultiplexes optical signals received from each switch from the set of switches, and sends, for each wavelength from the set of wavelengths, optical signals for that wavelength to the server from the set of servers.

Abstract: In some embodiments, an apparatus includes an optical detector that can sample asynchronously an optical signal from an optical component that can be either an optical transmitter or an optical receiver. In such embodiments, the apparatus also includes a processor operatively coupled to the optical detector, where the processor can calculate a metric value of the optical signal without an extinction ratio of the optical signal being measured. The metric value is proportional to the extinction ratio of the optical signal. In such embodiments, the processor can define an error signal based on the metric value of the optical signal and the processor can send the error signal to the optical transmitter such that the optical transmitter modifies an output optical signal.

Abstract: In some embodiments, an apparatus includes an optical transceiver that includes a first set of electrical transmitters operatively coupled to a switch. Each electrical transmitter from the first set of electrical transmitters is configured to transmit an electrical signal from a set of electrical signals. In such embodiments, the switch is configured to switch an electrical signal from the set of electrical signals such that the set of electrical signals are transmitted via a second set of electrical transmitters. Each electrical transmitter from the second set of electrical transmitters is operatively coupled to an optical transmitter from a set of optical transmitters. The set of optical transmitters is operatively coupled to an optical multiplexer. In such embodiments, at least one electrical transmitter from the second set of electrical transmitters is associated with a failure within the optical transceiver.

Abstract: In some embodiments, an apparatus includes an optical transmitter module that can be electrically coupled to an electrical serializer/deserializer and a controller. The optical transmitter module can include an electrical detector that can receive an in-band signal. The electrical detector can send to the controller a first power error signal and a second power error signal based on the in-band signal. The controller can send a correction control signal to the electrical serializer/deserializer based on the first power error signal and the second power error signal such that the electrical serializer/deserializer sends a pre-emphasized signal to the optical transmitter module based on the correction control signal. In such embodiments, the first power error signal, the second power signal and the correction control signal are out-of-band signals.

Abstract: In some embodiments, a system includes a set of servers, a set of switches within a switch fabric, and an optical device. The optical device is operatively coupled to the set of servers via a first set of optical fibers. Each server from the set of servers is associated with at least one wavelength from a set of wavelengths upon connection to the optical device. The optical device is operatively coupled to each switch from a set of switches via an optical fiber from a second set of optical fibers. The optical device, when operative, wavelength demultiplexes optical signals received from each switch from the set of switches, and sends, for each wavelength from the set of wavelengths, optical signals for that wavelength to the server from the set of servers.

Abstract: In some embodiments, an apparatus includes an optical transceiver that includes a first set of electrical transmitters operatively coupled to a switch. Each electrical transmitter from the first set of electrical transmitters is configured to transmit an electrical signal from a set of electrical signals. In such embodiments, the switch is configured to switch an electrical signal from the set of electrical signals such that the set of electrical signals are transmitted via a second set of electrical transmitters. Each electrical transmitter from the second set of electrical transmitters is operatively coupled to an optical transmitter from a set of optical transmitters. The set of optical transmitters is operatively coupled to an optical multiplexer. In such embodiments, at least one electrical transmitter from the second set of electrical transmitters is associated with a failure within the optical transceiver.

Abstract: In some embodiments, an apparatus includes a first optical transceiver. The first optical transceiver includes a set of optical transmitters, an optical multiplexer operatively coupled to the set of optical transmitters, and a variable optical attenuator operatively coupled to the optical multiplexer. The variable optical attenuator is configured to receive a control signal from a controller of the first optical transceiver and modulate a signal representing control information with an output from the optical multiplexer. The control information is associated with the control signal and for a second optical transceiver operatively coupled to the first optical transceiver.

Abstract: In some embodiments, an apparatus includes an automatic integrated circuit (IC) handler having a change kit. The change kit has a plunger moveably disposable onto an automatic test equipment (ATE). In such embodiments, the ATE is configured to receive an integrated circuit having an optical interface. The plunger has a first position and a second position. In such embodiments, the plunger is out of contact with the integrated circuit when the plunger is in the first position. The plunger includes an optical connector operatively coupled to the optical interface of the integrated circuit when the plunger is in the second position.

Abstract: A system is configured to determine a first power level of a first signal output from a first modulator, and determine a second power level of a second signal output from a second modulator. The first signal may include a first optical signal associated with a particular polarization orientation, and the second signal may include a second optical signal associated with the particular polarization orientation. The system is configured to determine a relationship between the first power level and the second power level, and to set, based on the relationship between the first power level and the second power level, a reverse bias voltage associated with the first modulator, where the reverse bias voltage may be used to control the first power level of the first signal.

Abstract: In some embodiments, an apparatus includes an optical transmitter module that can be electrically coupled to an electrical serializer/deserializer and a controller. The optical transmitter module can include an electrical detector that can receive an in-band signal. The electrical detector can send to the controller a first power error signal and a second power error signal based on the in-band signal. The controller can send a correction control signal to the electrical serializer/deserializer based on the first power error signal and the second power error signal such that the electrical serializer/deserializer sends a pre-emphasized signal to the optical transmitter module based on the correction control signal. In such embodiments, the first power error signal, the second power signal and the correction control signal are out-of-band signals.

Abstract: In some embodiments, an apparatus includes an optical detector that can sample asynchronously an optical signal from an optical component that can be either an optical transmitter or an optical receiver. In such embodiments, the apparatus also includes a processor operatively coupled to the optical detector, where the processor can calculate a metric value of the optical signal without an extinction ratio of the optical signal being measured. The metric value is proportional to the extinction ratio of the optical signal. In such embodiments, the processor can define an error signal based on the metric value of the optical signal and the processor can send the error signal to the optical transmitter such that the optical transmitter modifies an output optical signal.

Abstract: A system is configured to determine a first power level of a first signal output from a first modulator, and determine a second power level of a second signal output from a second modulator. The first signal may include a first optical signal associated with a particular polarization orientation, and the second signal may include a second optical signal associated with the particular polarization orientation. The system is configured to determine a relationship between the first power level and the second power level, and to set, based on the relationship between the first power level and the second power level, a reverse bias voltage associated with the first modulator, where the reverse bias voltage may be used to control the first power level of the first signal.

Abstract: An access network includes an access device having an optical interface module that outputs a plurality of pairs of optical communication signals, each of the pairs of optical communication signals comprising a modulated optical transmit signal and an unmodulated optical receive signal, each of the pairs of optical communication signals having a different wavelength. A customer premise equipment (CPE) comprises an optical interface module to receive the modulated optical transmit signal and the unmodulated optical receive signal for any of the plurality of pairs of optical communication signals. The optical interface module includes a receive module to demodulate the modulated optical transmit signal into inbound symbols and a transmit module having an optical modulator and reflective optics to modulate the unmodulated optical receive signal in accordance with a data signal and reflect a modulated optical receive signal to communicate outbound data symbols to the access device.

Abstract: In some embodiments, an apparatus includes an optical transceiver system that includes a set of optical transmitters and a backup optical transmitter. In such embodiments, each optical transmitter from the set of optical transmitter can transmit at a unique wavelength from a set of wavelengths. The backup optical transmitter can transmit at a wavelength from the set of wavelengths when an optical transmitter from the set of optical transmitters associated with that wavelength fails. In other embodiments, an apparatus includes an optical transceiver system that includes a set of optical receivers and a backup optical receiver. The backup optical receiver can receive at a wavelength from the set of wavelengths when an optical receiver from the set of optical receivers associated with that wavelength fails.

Abstract: In some embodiments, an apparatus includes an optical detector that can sample asynchronously an optical signal from an optical component that can be either an optical transmitter or an optical receiver. In such embodiments, the apparatus also includes a processor operatively coupled to the optical detector, where the processor can calculate a metric value of the optical signal without an extinction ratio of the optical signal being measured. The metric value is proportional to the extinction ratio of the optical signal. In such embodiments, the processor can define an error signal based on the metric value of the optical signal and the processor can send the error signal to the optical transmitter such that the optical transmitter modifies an output optical signal.

Abstract: In some embodiments, an apparatus includes a coherent optical receiver that can receive during a first time period a set of in-phase signals and a set of quadrature signals having a skew from the set of in-phase signals. The coherent receiver can blindly determine a delay between the set of in-phase signals and the set of quadrature signals based on the set of in-phase signals and the set of quadrature signals. The delay includes an intersymbol portion and an intrasymbol portion. The coherent optical receiver can apply the delay at a second time after the first time period such that a skew after the second time is less than the skew at the first time period.

Abstract: This disclosure describes the Fast Chromatic Dispersion Estimation (FCDE) techniques which corrects for chromatic dispersion in high data rate optical communications systems such as some coherent optical communications systems. FCDE may utilize transform such as fast-Fourier transforms to estimate the chromatic dispersion. From an estimate of the chromatic dispersion, the techniques may determine filter tap coefficients for compensating the chromatic dispersion.

Abstract: In some embodiments, an apparatus includes an optical transmitter system that defines an interferometric structure and has an in-phase portion and a quadrature portion. The optical transmitter system has a transmission configuration and a calibration configuration. The interferometric structure can produce an output associated with a skew between the in-phase portion and the quadrature portion of the optical transmitter system when in the calibration configuration. The skew is associated with a digital domain, an analog domain and an optical domain of the optical transmitter system.

Abstract: In some embodiments, an apparatus includes an optical transceiver system that includes a set of optical transmitters and a backup optical transmitter. In such embodiments, each optical transmitter from the set of optical transmitter can transmit at a unique wavelength from a set of wavelengths. The backup optical transmitter can transmit at a wavelength from the set of wavelengths when an optical transmitter from the set of optical transmitters associated with that wavelength fails. In other embodiments, an apparatus includes an optical transceiver system that includes a set of optical receivers and a backup optical receiver. The backup optical receiver can receive at a wavelength from the set of wavelengths when an optical receiver from the set of optical receivers associated with that wavelength fails.