According to one embodiment of the present invention, an apparatus and method for transmitting and receiving signals in a wireless communication system comprise receiving an optical signal including an interference signal and a target signal, attenuating the interference signal, and converting the optical signal in which the interference signal is attenuated, into electric signals via a photodiode array, wherein a transceiver comprises a first optical filter upon which the optical signal is incident, and a second optical filter upon which the optical signal having passed through the first optical filter is incident, wherein the interference signal may be attenuated through the first optical filter and the second optical filter.

According to one embodiment of the present invention, an apparatus and method for transmitting and receiving signals in a wireless communication system comprise receiving an optical signal including an interference signal and a target signal, attenuating the interference signal, and converting the optical signal in which the interference signal is attenuated, into electric signals via a photodiode array, wherein a transceiver comprises a first optical filter upon which the optical signal is incident, and a second optical filter upon which the optical signal having passed through the first optical filter is incident, wherein the interference signal may be attenuated through the first optical filter and the second optical filter.

A circuit and method for providing high-voltage radio-frequency (RF) energy to an instrument at multiple frequencies includes a plurality of inputs each configured to receive an RF voltage signal oscillating at a corresponding frequency, and a step-up circuit for generating magnified RF voltage signals based on the received RF voltage signals. The step-up circuit includes an LC network operable to isolate the RF voltage signals at the plurality inputs from one another while preserving a voltage magnification from each input to a common output at each of the corresponding frequencies.

A DC offset cancellation circuit and a DC offset cancellation method are disclosed. The DC offset cancellation circuit comprises a high-speed amplifier, a voltage comparator, a microprocessor, and a digital-to-analog converter. The high-speed amplifier comprises an input stage with a DC offset cancellation function, an amplification stage, and an output buffer stage. The voltage comparator is connected to the output buffer stage. The microprocessor is connected to the voltage comparator. The digital-to-analog converter is connected to the microprocessor. The digital-to-analog converter is connected to the input stage.

There may be provided detection circuit that may include (i) a photodiode that may be configured to convert radiation to a photodiode electrical signal; (ii) a photodiode bias circuit that may be configured to bias the photodiode, wherein the photodiode bias circuit may include a photodiode bias voltage supply and a photodiode bias capacitor; and (iii) a differential transimpedance amplifier that may be configured to amplify the photodiode electrical signal to provide a differential voltage. The differential transimpedance amplifier may include an amplification circuit and an additional circuit, wherein the amplification circuit may include a positive input port, a negative input port, a positive output port, a negative output port and a common mode input port. The photodiode bias voltage supply may be a floating voltage supply.

A communication device effectively transmits high-speed data while being less affected by restrictions of an environment by adjusting a communication channel depending on an optical communication environment.

Systems and methods for constellation shaping using low rate loss bit-level distribution matchers include receiving blocks of input bits and, for each input block of a predetermined size, assigning a respective codeword of a predetermined output block size. The number of bits of a given bit value in the codeword is dependent on a predetermined target probability distribution. A one-to-one mapping exists between each possible combination of input bits and a codeword for input blocks containing the combination. Some codewords include a number of bits having the given bit value that is different than the predetermined target probability distribution, but an average number of bits having the given bit value in the available codewords meets the predetermined target probability distribution. The disclosed methods result in more available codewords and a lower rate loss than in bit-level distribution matchers with a constant modulus, while achieving similar shaping.

Aspects of the present disclosure are directed to the mitigation of multi-path interference from quasi-single-mode fiber using hybrid span configuration and digital signal processing wherein a hybrid span of quasi-single mode fibers and single-mode fibers are used to configure the hybrid span. Additional aspects are directed to introducing a low-baud rate sub-banding signal to reduce the number of DD-LMS taps required when compensating the multi-path interference as the low-baud rate signal requires fewer taps to cover a given range of MPI as compared to a high-baud rate signal. Finally further aspects are directed to an ALMS equalizer which further reduces the number of equalizer taps by shifting its center tap towards the right if higher-order modes transmit slower than a fundamental mode, otherwise the center tap is shifted to the left.

An optical communication module includes a module board housed in a casing, a VCSEL and a driving IC mounted on a mounting surface of the module board, a lens holder mounted on the mounting surface of the module board, a lens block held by the lens holder, a plurality of thermal vias passing through the module board, and a first fixing screw and a second fixing screw passing through the module board to be screwed into the casing so as to press a back surface of the module board against a bottom surface of the casing, and the first fixing screw and the second fixing screw are each arranged in a region between the plug connector and the lens holder and on either outer side of the lens holder.

The present invention relates to a method for optimizing performance of a multi-span optical fiber network. Each span has an associated optical transmission fiber connected to an associated optical amplifier. Gain and output power of the associated optical amplifier are respectively controlled independently. An amplifier noise figure respectively depends on the gain of the associated optical amplifier, with each associated optical amplifier further connected to launch optical signals into a remainder of a corresponding optical transmission line. The method includes the steps of for each span, computing the amplifier noise figure and a non-linear noise generated in the span based on information about the span and using the computed amplifier noise figure and the computed non-linear noise to compute an optimum launch power, and optimizing performance of the multi-span optical fiber network based on the computed optimum launch powers of all spans.