An embodiment includes a host-equalized optical transceiver. The host-equalized optical transceiver includes a driver analog interface, a linear laser diode driver (LLDD), and an optical transmitter. The driver analog interface is configured to interface with a host integrated circuit (IC) of a host system. The LLDD is directly electrically coupled to a host IC of the host system via the driver analog interface. The LLDD is configured to receive an equalized electrical data signal directly from the host IC via the driver analog interface and to generate a driving signal based on the equalized electrical data signal. The equalized electrical data signal is a linear signal. The optical transmitter is electrically coupled to the LLDD. The optical transmitter is configured to receive the driving signal from the LLDD and to generate an optical signal that is representative of the driving signal.

An apparatus includes a finite impulse response (FIR) filter to receive a digital signal and a transmitter, operatively coupled to the FIR filter, to transmit an analog signal, converted from the digital signal, to a communication channel. The FIR filer is configured to change at least one operating parameter based on a bandwidth of the analog signal after transmission in the communication channel. The bandwidth of the analog signal is estimated, using an estimator, based at least in part on raw sampling data generated by an analog-to-digital converter (ADC) operatively coupled to the transmitter.

In some embodiments, an apparatus includes a memory and a processor operatively coupled to the memory. The processor is configured to be operatively coupled to a first optical transponder and a second optical transponder. The processor is configured to receive, from the second optical transponder, a signal representing a skew value of an optical signal and a signal representing a bit-error-rate (BER) value of the optical signal. The skew value is associated with a skew between an in-phase component of the optical signal and a quadrature component of the optical signal. The processor is configured to determine, based on at least one of the skew value or the BER value, if a performance degradation of the first optical transponder satisfies a threshold. The processor is configured to send a control signal to the first optical transponder to adjust a pulse shaping or a data baud rate of the first optical transponder.

A method and apparatus for transporting data through a single optical fiber (SOF) the method comprising the steps of providing (S1) transmission Tx, wavelength division multiplexed, WDM, data channels and reception Rx, wavelength division multiplexed, WDM, data channels having the same frequency grid with frequency gaps between the WDM data channels; frequency shifting (S2) the Tx-WDM data channels and/or the Rx-WDM data channels to avoid spectral overlap between the Tx-WDM data channels and the Rx-WDM data channels; combining (S3) the frequency shifted Tx-WDM data channels and the frequency shifted Rx-WDM data channels; and transporting (S4) data via the combined WDM data channels through said single optical fiber (SOF) in opposite directions.

A network element includes a transmitting amplifier configured to transmit to a first optical fiber, wherein the transmitting amplifier has a pump laser; and an optical monitor connected to a second optical fiber and configured to detect a portion of optical power thereon; wherein the pump laser is modulated to convey a signal to a second optical monitor in a second network element connected to the first optical fiber, when the transmitting amplifier is one of in a safety mode and has no input.

Cost-effective high-data-rate optical data transceivers are presented, comprising an electronic analog transversal filter simultaneously providing one or more of bandwidth compensation and forward impairment compensations for the transmitted optical signal.

A circuit and method for mitigating multi-path interference in direct detection optical systems is provided. Samples of an optical signal having a pulse amplitude modulated (PAM) E-field are processed by generating a PAM level for each sample. For each sample, the sample is subtracted from the respective PAM level to generate a corresponding error sample. The error samples are lowpass filtered to produce estimates of multi-path interference (MPI). For each sample, one of the estimates of MPI is combined with the sample to produce an interference-mitigated sample.

An optical communication system according to the present invention cancels waveform distortion due to wavelength dispersion by extracting the spectrum of a transmitted optical signal and passing the optical signal to a fiber having a dispersion value opposite to a dispersion amount corresponding to a transmission distance received by the spectrum component and compensates for a transmission path loss due to the fiber having the opposite dispersion value using optical splitters having different split ratios. With this configuration, the present invention can compensate for waveform distortion due to wavelength dispersion by a simple method in an access network and achieve an increase in the reachable transmission distance of the farthest user or an increase in the number of connectable users.

A receiver (e.g., for a 10 G fiber communications link) includes an interleaved ADC coupled to a multi-channel equalizer that can provide different equalization for different ADC channels within the interleaved ADC. That is, the multi-channel equalizer can compensate for channel-dependent impairments. In one approach, the multi-channel equalizer is a feedforward equalizer (FFE) coupled to a Viterbi decorder, for example, a sliding block Viterbi decoder (SBVD); and the FFE and/or the channel estimator for the Viterbi decoder are adapted using the LMS algorithm.

Embodiments of the present application relate to a method for implementing Turbo equalization compensation. The equalizer divides a first data block into n data segments, where D bits in two adjacent data segments in the n data segments overlap, performs recursive processing on each data segment in the n data segments, before the recursive processing, merges the n data segments to obtain a second data block; and performs iterative decoding on the second data block, to output a third data block, where data lengths of the first data block, the second data block, and the third data block are all 1/T of a code length of a LDPC convolutional code.