Methods and systems for a distributed Mach-Zehnder Interferometer (MZI) with an integrated feed forward equalizer (FFE) may include a photonic chip comprising an optical modulator having diode drivers, local voltage domain splitters, and delay elements, where each is distributed along a length of the optical modulator. Outputs of the delay elements may be coupled to inputs of the local domain splitters, and outputs of the local voltage domain splitters may be coupled to inputs of the diode drivers. A feed forward equalization (FFE) module comprising a configurable delay element with inverted outputs coupled to one of the delay elements along the length of the modulator, may be coupled to a local voltage domain splitter. An input electrical signal may be received and delayed using the delay elements and coupled to the local domain splitters, and input electrical signals for the diode drivers may be generated using the local domain splitters.

An object is to output an optical signal accurately corresponding to a data signal. A pluggable optical module (100) includes a pluggable electric connector (11), a control unit (12), an optical signal output unit (13), and a pluggable optical receptor (14). The pluggable electric connector (11) can communicate a modulation signal (MOD) and a control signal (CON1) with an optical communication apparatus (92). The optical signal output unit (13) outputs an optical signal (LS) modulated by the modulation scheme by the control signal (CON1) in response to the modulation signal (MOD). The pluggable optical receptor (14) is configured in such a manner that an optical fiber (91) is insertable into and removable from the pluggable optical receptor (14). The pluggable optical receptor (14) can output the optical signal (LS) output from the optical signal output unit (13). The control unit (12) controls the optical signal output unit (13) to output the optical signal (LS) of a modulation amplitude set corresponding to the modulation signal (MOD) in the modulation scheme specified by the control signal (CON1).

An electro-absorption bias circuit may include a temperature sensor. The electro-absorption bias circuit may include a controller to provide a temperature-dependent control signal based on data received from the temperature sensor. The electro-absorption bias circuit may include a power supply to provide an output voltage based on the temperature-dependent control signal from the controller. The electro-absorption bias circuit may include an electro-absorption driving circuit to output a bias voltage applied to the output voltage provided by the power supply.

An optical transmission apparatus includes an optical transmitter including an optical modulator and an observation optical modulator that attenuate optical power of input continuous wave light by an electro-absorption effect and output the light. The optical modulator performs pulse amplitude modulation on the continuous wave light and outputs the optical signal. The apparatus also includes: a bias voltage generation unit that generates a direct-current bias voltage and outputs the direct-current bias voltage to the optical modulator and the observation optical modulator; a modulation signal generation unit that generates an electrical signal for pulse amplitude modulation and outputs the electrical signal to the optical modulator; and a bias voltage control unit that instructs the bias voltage generation unit to adjust the direct-current bias voltage on the basis of an absorption amount of optical power in the optical modulator and an absorption amount of optical power in the observation optical modulator.

An optoelectronic device for quadrature-amplitude modulation (QAM) and a method of modulating light according to the same. The device comprising: an input waveguide; two intermediate waveguides, each coupled to the input waveguide via an input coupler; and an output waveguide, coupled to each of the intermediate waveguides via an output coupler; wherein each intermediate waveguide includes a modulating component connected in series with a phase shifting component, and each modulating component is connected to a respective electronic driver, the electronic drivers together being operable to produce a QAM-N modulated output from light entering the device from the input waveguide.

A processor comprises instructions to adjust a bias of an input signal in order to decrease a duty cycle of a pulse modulated optical signal. The bias can be increased, decreased, or maintained in response to one or more measured values of the signal. In many embodiments, a gain of the signal is adjusted with the bias in order to inhibit distortion. The bias can be adjusted slowly in order to inhibit audible noise, and the gain can be adjusted faster than the bias in order to inhibit clipping of the signal. In many embodiments, one or more of the bias or the gain is adjusted in response to a value of the signal traversing a threshold amount. The value may comprise a trough of the signal traversing the threshold.

A pluggable optical module includes a pluggable electric connector, a control unit, an optical signal output unit, and a pluggable optical receptor. The pluggable electric connector can communicate a modulation signal and a control signal with an optical communication apparatus. The optical signal output unit outputs an optical signal modulated by the modulation scheme by the control signal in response to the modulation signal. The pluggable optical receptor is configured in such a manner that an optical fiber is insertable into and removable from the pluggable optical receptor. The pluggable optical receptor can output the optical signal output from the optical signal output unit. The control unit controls the optical signal output unit to output the optical signal of a modulation amplitude set corresponding to the modulation signal in the modulation scheme specified by the control signal.

A processor comprises instructions to adjust a bias of an input signal in order to decrease a duty cycle of a pulse modulated optical signal. The bias can be increased, decreased, or maintained in response to one or more measured values of the signal. In many embodiments, a gain of the signal is adjusted with the bias in order to inhibit distortion. The bias can be adjusted slowly in order to inhibit audible noise, and the gain can be adjusted faster than the bias in order to inhibit clipping of the signal. In many embodiments, one or more of the bias or the gain is adjusted in response to a value of the signal traversing a threshold amount. The value may comprise a trough of the signal traversing the threshold.

Described herein is a solution to address the intrinsic nonlinearity of analog signals and the restrictions this places on the signals dynamic range. The subject matter described herein produces linear electro-optic modulation over a dramatically wider range of the input signal amplitude. This is accomplished by a distributed multiwavelength design that folds the large dynamic range across multiple linear subranges, with each subrange being addressed using an optical wavelength. As a result, the subrange within the wide dynamic range of the input signal is captured by the linear portion of the transfer function of a single transfer function. Several physical implementations of this subject are presented herein. This innovation enables the efficient use of optical links for the transmission and processing of analog and multilevel signals, overcoming the limitations that were once hindering progress in this field.

A radio frequency (RF) photonic equalizer may include a first electro-optic (E/O) modulator configured to modulate an optical carrier based upon an RF input signal, a stimulated Brillouin scattering (SBS) medium coupled to the first E/O modulator, and a second E/O modulator configured to modulate the optical carrier based upon an equalizing function waveform. An optical circulator may be coupled to the SBS medium and the second E/O modulator, and a photodetector may be coupled to the optical circulator.