An optical reception device includes a coefficient update section which optimizes a dispersion coefficient used in compensation of wavelength dispersion of a received signal obtained by receiving an optical signal according to a coherent detection method and a phase rotation amount used in compensation of a nonlinear optical effect of the received signal, and a transmission characteristic estimation section which estimates a transmission characteristic of a transmission line by using the optimized dispersion coefficient and the optimized phase rotation amount.

An optical reception device includes a coefficient update section which optimizes a dispersion coefficient used in compensation of wavelength dispersion of a received signal obtained by receiving an optical signal according to a coherent detection method and a phase rotation amount used in compensation of a nonlinear optical effect of the received signal, and a transmission characteristic estimation section which estimates a transmission characteristic of a transmission line by using the optimized dispersion coefficient and the optimized phase rotation amount.

There is herein provided a method for measuring the GOSNR that can be implemented using commercial-grade transceivers and which accounts for linear optical impairments (e.g. PMD, PDL and CD) and transceiver intrinsic impairments. The method may be implemented using an Optical Spectrum Analyzer (OSA) and either the system transceivers or other commercial-grade transceivers. The proposed measurement method is based on mixed optical and electronic technologies, using an OSA and a transceiver pair. By measuring a signal quality metric Q.sub.m and the OSNR under varied power and ASE noise conditions, a constant value R.sub.BW that relates the GOSNR to the signal quality metric Q.sub.m is derived. The GOSNR is then obtained from these results.

Methods and systems for low complexity interference cancellation in multichannel optical transmission. Local or self-iteration is performed one or more times between an expected propagation decision feedback equalizer and a soft demapper. Following local iteration, a soft decision forward error correction decoder determines bit log-likelihood ratios, which are fed back to the expected propagation decision feedback equalizer and soft demapper for further self-iteration. Global iteration involving the decoder can also be performed one or more times before a bitstream is decoded.

Methods and systems for low complexity interference cancellation in multichannel optical transmission. Local or self-iteration is performed one or more times between an expected propagation decision feedback equalizer and a soft demapper. Following local iteration, a soft decision forward error correction decoder determines bit log-likelihood ratios, which are fed back to the expected propagation decision feedback equalizer and soft demapper for further self-iteration. Global iteration involving the decoder can also be performed one or more times before a bitstream is decoded.

Deep neural network (DNN) has been used for various applications to provide inference, regression, classification, and prediction. Although a high potential of DNN has been successfully demonstrated in literature, most DNN requires high computational complexity and high power operation for real-time processing due to a large number of multiply-accumulate (MAC) operations. The present invention provides a way to realize hardware-friendly MAC-less DNN framework with round-accumulate (RAC) operation operations based on power-of-two (PoT) weights. The method and system are based on the realization that rounding-aware training for powers-of-two expansion can eliminate the need of multiplier components from the system without causing any performance loss. In addition, the method and system provide a way to reduce the number of PoT weights based on a knowledge distillation using a progressive compression of an over-parameterized DNN. It is can realize high compression, leading to power-efficient inference for resource-limited hardware implementation such as micro processors and field-programmable gate arrays. A compacting rank is optimized with additional DNN model in a reinforcement learning framework. A rounding granularity is also successively decremented and mixed-order PoT weights are obtained for low-power processing. Another student model is also designed in parallel for a knowledge distillation to find a Pareto-optimal trade-off between performance and complexity.

The present application is directed to techniques and systems for extension of unrepeatered submarine fiber links to provide an increase in reach of unrepeatered fiber transmission. Both single channel unrepeatered systems and multiple channel unrepeatered systems can be used. The multiple channel unrepeatered systems can further employ nonlinearity compensation. The present application is also directed to methods of signal transmission using the unrepeatered systems.

The present application is directed to techniques and systems for extension of unrepeatered submarine fiber links to provide an increase in reach of unrepeatered fiber transmission. Both single channel unrepeatered systems and multiple channel unrepeatered systems can be used. The multiple channel unrepeatered systems can further employ nonlinearity compensation. The present application is also directed to methods of signal transmission using the unrepeatered systems.

An optical or an optoelectronic device and methods are provided for data transmission across two interconnects. First, an electrical signal is obtained from an interconnect. Next, the electrical signal is modulated. Within the modulated electrical signal, an occurrence of a transition is determined, in which a change in a power of the electrical signal by more than a threshold amount. In response to the determination of the occurrence of the transition, coefficients indicative of respective amounts of compensation to resolve or mitigate nonlinearities associated with the transition are determined. According to the coefficients, a filter is applied in a vicinity of the transition to obtain a modified electrical signal. The modified electrical signal is converted into an optical signal and coupled to a fiber to transmit the optical signal to a destination at a second interconnect.

An optical or an optoelectronic device and methods are provided for data transmission across two interconnects. First, an electrical signal is obtained from an interconnect. Next, the electrical signal is modulated. Within the modulated electrical signal, an occurrence of a transition is determined, in which a change in a power of the electrical signal by more than a threshold amount. In response to the determination of the occurrence of the transition, coefficients indicative of respective amounts of compensation to resolve or mitigate nonlinearities associated with the transition are determined. According to the coefficients, a filter is applied in a vicinity of the transition to obtain a modified electrical signal. The modified electrical signal is converted into an optical signal and coupled to a fiber to transmit the optical signal to a destination at a second interconnect.