A digital-to-analog converter has a first interface coupled to a second interface through one or more modulation circuits. The circuits include a first coupler connected to the first interface; a first waveguide with a first lead connected to the first coupler, a first end, and a first length running therebetween. The first lead and the first end are coupled by a first switch. The circuits also include: a second coupler connected to the first interface; a second waveguide having a second lead connected to the second coupler, a second end, and a second length running therebetween, the second lead and the second end coupled by a second switch along the second length; and an optical combiner connected to the ends of the waveguides. The second interface is connected to the optical combiner of the modulation circuits. Output from the second interface is an optical signal capable of carrying binary information.

The nonlinearities of cascaded and series configurations of Mach-Zehnder electrooptic modulators are utilized to increase signal bandwidth and boost signal fidelity in electronic digital to analog converters.

The nonlinearities of cascaded and series configurations of Mach-Zehnder electrooptic modulators are utilized to increase signal bandwidth and boost signal fidelity in electronic digital to analog converters.

A digital-to-analog converter has a first interface coupled to a second interface through one or more modulation circuits. The circuits include a first coupler connected to the first interface; a first waveguide with a first lead connected to the first coupler, a first end, and a first length running therebetween. The first lead and the first end are coupled by a first switch. The circuits also include: a second coupler connected to the first interface; a second waveguide having a second lead connected to the second coupler, a second end, and a second length running therebetween, the second lead and the second end coupled by a second switch along the second length; and an optical combiner connected to the ends of the waveguides. The second interface is connected to the optical combiner of the modulation circuits. Output from the second interface is an optical signal capable of carrying binary information.

A digital-to-analog converter has a first interface coupled to a second interface through one or more modulation circuits. The circuits include a first coupler connected to the first interface; a first waveguide with a first lead connected to the first coupler, a first end, and a first length running therebetween. The first lead and the first end are coupled by a first switch. The circuits also include: a second coupler connected to the first interface; a second waveguide having a second lead connected to the second coupler, a second end, and a second length running therebetween, the second lead and the second end coupled by a second switch along the second length; and an optical combiner connected to the ends of the waveguides. The second interface is connected to the optical combiner of the modulation circuits. Output from the second interface is an optical signal capable of carrying binary information.

This application discloses a temperature feedback control apparatus, method. The method includes two electric switches, a feedback control unit and an optical component. A first electric switch is configured to control that only a first channel of at least two channels that correspond to the first electric switch is conducted at a moment, to feed back an optical signal of a target optical component connected to the first channel to the feedback control unit. The feedback control unit is configured to calculate temperature of the corresponding optical component based on an electrical signal converted from the optical signal, to obtain a control signal. The second electric switch is configured to control, when the first channel is conducted, that only the second channel is conducted, to transmit the control signal to the target optical component to adjust its temperature. The optical component connects to both the first and second channels.

This application discloses a temperature feedback control apparatus, method. The method includes two electric switches, a feedback control unit and an optical component. A first electric switch is configured to control that only a first channel of at least two channels that correspond to the first electric switch is conducted at a moment, to feed back an optical signal of a target optical component connected to the first channel to the feedback control unit. The feedback control unit is configured to calculate temperature of the corresponding optical component based on an electrical signal converted from the optical signal, to obtain a control signal. The second electric switch is configured to control, when the first channel is conducted, that only the second channel is conducted, to transmit the control signal to the target optical component to adjust its temperature. The optical component connects to both the first and second channels.

An optical transmission device includes: a frontend circuit, a converter, an equalizer, a recovery, spectrum detector a correction information generator, and a transmitter. The frontend circuit converts an optical signal received via an optical network into an electric signal. The converter converts an output signal of the frontend circuit into a digital signal. The equalizer equalizes the digital signal or a second digital signal that is generated based on the digital signal. The recovery recovers a symbol from an output signal of the equalizer. The spectrum detector detects a reception spectrum of the optical signal based on the digital signal or the second digital signal. The correction information generator generates, according to the reception spectrum, correction information for correcting a shape of a transmission spectrum of the optical signal. The transmitter transmits the correction information to the source device.

An optical transmission device includes: a frontend circuit, a converter, an equalizer, a recovery, spectrum detector a correction information generator, and a transmitter. The frontend circuit converts an optical signal received via an optical network into an electric signal. The converter converts an output signal of the frontend circuit into a digital signal. The equalizer equalizes the digital signal or a second digital signal that is generated based on the digital signal. The recovery recovers a symbol from an output signal of the equalizer. The spectrum detector detects a reception spectrum of the optical signal based on the digital signal or the second digital signal. The correction information generator generates, according to the reception spectrum, correction information for correcting a shape of a transmission spectrum of the optical signal. The transmitter transmits the correction information to the source device.

A method and a system for adding a floating analog voltage signal over a reference analog voltage signal. The system and the method may accurately control the value of the floating analog voltage signal—using an optical feedback path, and may directly add the floating analog voltage signal over the reference analog voltage signal.