37results about "Optical NRZ to RZ conversion" patented technology

The method includes: receiving a first Non Return to Zero (NRZ) data signal and a synchronous clock signal, and performing Return to Zero (RZ) processing to generate a first complementary RZ data signal pair; receiving a second NRZ data signal and a synchronous clock signal, and performing RZ processing to generate a second complementary RZ data signal pair; and modulating the first complementary RZ data signal pair and the second complementary RZ data signal pair on light to generate an RZ-Differential Quadrature Phase Shift Keying (RZ-DQPSK) optical signal. Through the method and device, RZ processing are performed on the NRZ data signals to generate the complementary RZ data signal pairs, and the complementary RZ data signal pairs are modulated on the light, thereby reducing the cost and the insertion loss of the entire device, lowering the requirements for input optical power and reducing the complexity of loop circuit control.

The present invention suppresses to a minimum the degradation of the transmission quality caused by chromatic dispersion characteristic of an optical transmission medium, and the interplay between the chromatic dispersion and non-linear optical effects in dense WDM transport systems. A baseband input data signal is pre-coded in advance by a pre-coding unit, phase modulation is carried out using a pre-coded signal by the optical phase modulating unit, and the phase modulated optical signal is converted to an RZ intensity modulated signal by the optical filter unit that performs phase-shift-keying to amplitude-shift-keying conversion. For example, an optical phase modulating unit generates an encoded DPSK phase modulated signal using a differential phase shirt keying (DPSK) format, and a phase modulated signal is converted to an RZ intensity modulated signal by the optical filter unit disposed downstream of the optical phase modulating unit.

A system for generating a return-to-zero differentially-phase-shift-keyed (RZ-DPSK) optical signal comprising:a driver comprising an N-level digital multilevel transformer (DMT) configured to receive a two level digital electrical signal representing 1s and 0s and output a N-level electrical signal, wherein N>2;an FM source configured to receive the N-level electrical signal output by the driver and generate an optical frequency modulated signal; andan optical spectrum reshaper (OSR) configured to receive the optical frequency modulated signal output by the FM source and generate the desired RZ-DPSK optical signal. A method for generating a return-to-zero differentially-phase-shift-keyed (RZ-DPSK) optical signal, the method comprising:(1) receiving a two level digital electrical signal representing 1s and 0s and outputting a N-level electrical signal, wherein N>2;(2) receiving the N-level electrical signal output and generating an optical frequency modulated signal; and(3) receiving the optical frequency modulated signal and generating the desired RZ-DPSK optical signal.

A fiber optic communication system comprising:an optical signal source adapted to receive a binary base signal having a bit period T, and generate a first signal, wherein the first signal is frequency modulated; andan optical spectrum reshaper (OSR) adapted to reshape the first signal into a second signal, wherein the second signal is amplitude modulated and frequency modulated;characterized in that:the optical signal source is a laser in which frequency modulation is generated by modulating the loss of the laser cavity.A method for transmitting a signal, comprising:receiving a binary base signal having a bit period T, and generating a first signal, wherein the first signal is frequency modulated; andreshaping the first signal into a second signal, wherein the second signal is amplitude modulated and frequency modulated;characterized in that:the first signal is frequency modulated by using a laser in which frequency modulation is generated by modulating the loss of the laser cavity.A fiber optic communication system comprising:an optical signal source adapted to receive a binary base signal having a bit period T, and generate a first signal, wherein the first signal is frequency modulated; andan optical spectrum reshaper (OSR) adapted to reshape the first signal into a second signal, wherein the second signal is amplitude modulated and frequency modulated;characterized in that:the optical signal source is a laser in which frequency modulation is generated by modulating the phase of the laser cavity.

A fiber optic communication system comprising:an optical signal source adapted to receive a binary base signal having a bit period T, and generate a first signal, wherein the first signal is frequency modulated; andan optical spectrum reshaper (OSR) adapted to reshape the first signal into a second signal, wherein the second signal is amplitude modulated and frequency modulated;characterized in that:the frequency excursion of the first signal is adjusted such that the frequency excursion is substantially equal to the ratio of the bit period of the digital base signal to total dispersion of the transmission fiber, whereby to increase the tolerance of the second signal to dispersion in a transmission fiber.

A fiber optic communication system comprising: an optical signal source adapted to receive a binary base signal having a bit period T, and generate a first signal, wherein the first signal is frequency modulated; and an optical spectrum reshaper (OSR) adapted to reshape the first signal into a second signal, wherein the second signal is amplitude modulated and frequency modulated; characterized in that: the optical signal source is a laser in which frequency modulation is generated by modulating the loss of the laser cavity. A method for transmitting a signal, comprising: receiving a binary base signal having a bit period T, and generating a first signal, wherein the first signal is frequency modulated; and reshaping the first signal into a second signal, wherein the second signal is amplitude modulated and frequency modulated; characterized in that: the first signal is frequency modulated by using a laser in which frequency modulation is generated by modulating the loss of the laser cavity. A fiber optic communication system comprising: an optical signal source adapted to receive a binary base signal having a bit period T, and generate a first signal, wherein the first signal is frequency modulated; and an optical spectrum reshaper (OSR) adapted to reshape the first signal into a second signal, wherein the second signal is amplitude modulated and frequency modulated; characterized in that: the optical signal source is a laser in which frequency modulation is generated by modulating the phase of the laser cavity.

There is therefore provided, in accordance with an embodiment of the present invention, a method for processing an amplitude modulated (AM) optical beam amplitude modulated with a modulation pattern having an extinction ratio (ER), said AM beam having a carrier frequency and a carrier frequency amplitude, the method comprising: estimating an absolute amplitude extremum for the AM beam that is either an absolute amplitude maximum or an absolute amplitude minimum, to which recurrent amplitude extrema of the AM beam are approximately equal; estimating a corresponding phase to which the phase of the AM beam is substantially equal whenever the amplitude of the AM beam is substantially equal to the amplitude extremum; and adjusting at least one of the magnitude and phase of the carrier amplitude of the AM beam responsive to the amplitude extremum and its corresponding phase to increase the extinction ratio of the modulation pattern.

The present invention suppresses to a minimum the degradation of the transmission quality caused by chromatic dispersion characteristic of an optical transmission medium, and the interplay between the chromatic dispersion and non-linear optical effects in dense WDM transport systems. A baseband input data signal is pre-coded in advance by a pre-coding unit, phase modulation is carried out using a pre-coded signal by the optical phase modulating unit, and the phase modulated optical signal is converted to an RZ intensity modulated signal by the optical filter unit that performs phase-shift-keying to amplitude-shift-keying conversion. For example, an optical phase modulating unit generates an encoded DPSK phase modulated signal using a differential phase shirt keying (DPSK) format, and a phase modulated signal is converted to an RZ intensity modulated signal by the optical filter unit disposed downstream of the optical phase modulating unit.

A phase modulation apparatus has a light source outputting continuous light, two phase modulators, and an intensity modulator. The phase modulation apparatus is provided with an RZ phase modulation circuit, in which the phase modulators phase-modulate the continuous light from the light source with data signals input to the phase modulators and generate two phase modulation optical signals, a phase shifter shifts the phase of one phase modulation optical signal by π / 2, and an intensity modulator intensity-modulates a multiplexed signal, combined with the other phase modulation optical signal, with an input clock signal CLK to convert the signal into an RZ signal, and, thus, to output the RZ signal, and a phase control circuit which adjusts the phases of the phase modulation optical signals generated by the phase modulator of the RZ phase modulation circuit so that the output of the RZ phase modulation circuit is maximum.

The invention provides an all-optical serial-parallel conversion system based on a wavelength division multiplexing technology. Multi-wavelength light is combined and shunted through the wavelength division multiplexing technology, conversion from a high-speed serial-parallel signal to a low-speed parallel signal is achieved by controlling on-off of a high-speed optical switch, a low-speed parallel non-return-to-zero code electric signal is obtained based on the code pattern conversion technology, and picosecond-magnitude all-optical serial-parallel conversion is achieved. The control signal characteristics and the switching speed of the optical switch are controlled; the all-optical serial-to-parallel conversion with a transparent code pattern is realized, the all-optical serial-to-parallel conversion without cache is realized, the time domain delay of a wavelength division multiplexing optical signal is realized by utilizing the dispersion time domain dispersion delay characteristic,the serial-to-parallel conversion is carried out through the high-speed optical switch switching unit, and a non-return-to-zero code electric signal is obtained through the code pattern conversion unit.

The invention discloses an integrated optical module error code tester based on PAM4. The integrated optical module error code tester comprises a main control unit, an interface unit and an upper computer. By integrating peripheral circuits such as a communication interface, a power supply circuit, an I / O interface and the like into a main control unit, the SoC performs power supply configurationand I / O signal definition according to different optical module types. The interface unit is connected with the main control unit through the pluggable connector, only the interface unit needs to be replaced when different optical module tests are carried out, and corresponding peripheral circuits do not need to be customized. The optical module interface circuit and the error code test module areboth integrated in the interface unit, and no cable is needed for connection, so that the loss in the test process is reduced, and NRZ / PAM4 signals with higher rate and PRBS code patterns with longerlength can be tested.

There is provided an optical modulation signal generating device in which an operation speed is not limited by a relaxation oscillation frequency of a laser, and high-speed modulation and long-distance transmission can be performed. The optical modulation signal generating device converts a signal from a signal source into an optical signal and outputs the optical signal to a transmission medium having frequency dispersion. The optical modulation signal generating device includes an optical source (102) for performing frequency modulation by the signal from the signal source to generate an optical signal having only a frequency modulation component, and a frequency filter (103) for converting the frequency modulation component of the optical signal into an intensity modulation component and a frequency modulation component.

An optical connecting apparatus has a light source outputting an optical signal indicating a plurality of wavelengths which correspond to a plurality of transmission channels, an optical transmit section and an optical receive section being mounted with integrated circuits and being connected to each other through an optical line of a single system, and a signal conversion section being inlet in the optical line and converting a phase modulated signal into an intensity modulated signal. The optical transmit section includes: a demultiplexer which separates the optical signal from the light source according to the transmission channels; an optical modulator unit which generates phase modulated signals by implementing phase modulation with optical signals from the demultiplexer by using a plurality of optical modulators whose operations are synchronized by a signal from the integrated circuit; and a multiplexer which multiplexes the phase modulated signals from the optical modulator unit and outputs the multiplexed phase modulated signals to the signal conversion section through the optical line. The optical receive section includes: a demultiplexer which separates the intensity modulated signal from the signal conversion section according to the transmission channels; and an optical receiver unit which converts the intensity modulated signals from the demultiplexer into electric signals.

The present invention pertains to method and apparatus for optically stretching an optical pulse to convert associated optical data from a first format to a second format. Moreover, the present invention pertains to method and apparatus for optically reducing the jitter of an optical data stream having optical pulses, enabling the transmission of low jitter optical data.

There is provided an optical modulation signal generating device in which an operation speed is not limited by a relaxation oscillation frequency of a laser, and high-speed modulation and long-distance transmission can be performed. The optical modulation signal generating device converts a signal from a signal source into an optical signal and outputs the optical signal to a transmission medium having frequency dispersion. The optical modulation signal generating device includes an optical source (102) for performing frequency modulation by the signal from the signal source to generate an optical signal having only a frequency modulation component, and a frequency filter (103) for converting the frequency modulation component of the optical signal into an intensity modulation component and a frequency modulation component.

A system for generating a return-to-zero differentially-phase-shift-keyed (RZ-DPSK) optical signal comprising: a driver comprising an N-level digital multilevel transformer (DMT) configured to receive a two level digital electrical signal representing 1s and 0s and output a N-level electrical signal, wherein N>2; an FM source configured to receive the N-level electrical signal output by the driver and generate an optical frequency modulated signal; and an optical spectrum reshaper (OSR) configured to receive the optical frequency modulated signal output by the FM source and generate the desired RZ-DPSK optical signal. A method for generating a return-to-zero differentially-phase-shift-keyed (RZ-DPSK) optical signal, the method comprising: (1) receiving a two level digital electrical signal representing 1s and 0s and outputting a N-level electrical signal, wherein N>2; (2) receiving the N-level electrical signal output and generating an optical frequency modulated signal; and (3) receiving the optical frequency modulated signal and generating the desired RZ-DPSK optical signal.

The invention pertains to method and system for generating low jitter optical data encoded in a first format, enabling the transmission of low jitter optical data encoded in the first format. Moreover, the invention pertains to utilizing an optical pulse stretcher to convert optical data encoded in a second format to optical data encoded in the first format.

A phase modulation apparatus has a light source outputting continuous light, two phase modulators, and an intensity modulator. The phase modulation apparatus is provided with an RZ phase modulation circuit, in which the phase modulators phase-modulate the continuous light from the light source with data signals input to the phase modulators and generate two phase modulation optical signals, a phase shifter shifts the phase of one phase modulation optical signal by π / 2, and an intensity modulator intensity-modulates a multiplexed signal, combined with the other phase modulation optical signal, with an input clock signal CLK to convert the signal into an RZ signal, and, thus, to output the RZ signal, and a phase control circuit which adjusts the phases of the phase modulation optical signals generated by the phase modulator of the RZ phase modulation circuit so that the output of the RZ phase modulation circuit is maximum.

Method and apparatus for time aligning first and second signals. The second signal is modulated by the first signal to provide a third signal. Frequency components of the third signal are then determined, the frequency components being indicative of time alignment between the first and second signals. The method and apparatus is particularly suitable for converting a Non-Return-to-Zero data signal to a Return-to-Zero data signal by modulating the Non-Return-to-Zero data signal with a Return-to-Zero pulse signal. The method and apparatus provides for the Non-Return-to-Zero data signal and the Return-to-Zero pulse signal being correctly time aligned in an automated manner without human intervention.

A fiber optic communication system comprising: an optical signal source adapted to receive a binary first signal and generate a binary second signal, wherein the binary first signal has an amplitude modulated component, wherein the binary second signal has an amplitude modulated component and a frequency modulated component, and further wherein the binary second signal is characterized in that the higher intensity 1 bits are red shifted relative to the lower intensity 0 bits; a semiconductor optical amplifier (SOA) adapted to receive the binary second signal and generate a binary third signal, wherein the binary third signal has an amplitude modulated component and a frequency modulated component, and further wherein the semiconductor optical amplifier operates in saturation; and an optical spectrum reshaper (OSR) adapted to reshape the binary third signal into a binary fourth signal, wherein the binary fourth signal has an amplitude modulated component and a frequency modulated component. A method for transmitting a signal, comprising: receiving a binary first signal having an amplitude modulated component and generating a binary second signal having an amplitude modulated component and a frequency modulated component, wherein the binary second signal is characterized in that the higher intensity 1 bits are red shifted relative to the lower intensity 0 bits; passing the binary second signal through a semiconductor optical amplifier (SOA) operating in saturation so as to generate a binary third signal, wherein the binary third signal has an amplitude modulated component and a frequency modulated component; and reshaping the binary third signal into a binary fourth signal, wherein the binary fourth signal has an amplitude modulated component and a frequency modulated component.

Provided is a signal processor for converting a signal that converts a return to zero (RZ) signal into a non-return to zero (NRZ) signal, in which two 2R (re-amplifying, re-shaping) regenerators are connected in parallel between an input waveguide and an output waveguide with different lengths from each other. The 2R regenerator includes: two semiconductor optical amplifiers having different lengths from each other; and phase control means connected to a short semiconductor optical amplifier. The RZ signal input by a length difference of the waveguide is delayed by a time difference of a half of one bit so that the 2R regenerated NRZ signal can be obtained.

The method includes: receiving a first Non Return to Zero (NRZ) data signal and a synchronous clock signal, and performing Return to Zero (RZ) processing to generate a first complementary RZ data signal pair; receiving a second NRZ data signal and a synchronous clock signal, and performing RZ processing to generate a second complementary RZ data signal pair; and modulating the first complementary RZ data signal pair and the second complementary RZ data signal pair on light to generate an RZ-Differential Quadrature Phase Shift Keying (RZ-DQPSK) optical signal. Through the method and device, RZ processing are performed on the NRZ data signals to generate the complementary RZ data signal pairs, and the complementary RZ data signal pairs are modulated on the light, thereby reducing the cost and the insertion loss of the entire device, lowering the requirements for input optical power and reducing the complexity of loop circuit control.

The optical single sideband modulator includes an amplitude modulator and a converter comprising a semiconductor optical amplifier, using the chirp effect to convert an amplitude modulated optical signal into a single sideband signal without a filter for eliminating one of the sidebands.

The present invention refers to a method for robust multi-level encoding of optical signals. The method uses a transmitter that transforms electric signals into optical signals and a receiver capable to transform optical signals into electric signals. The transmitter is capable to generate optical pulses having at least two different durations. The amplitudes of the pulses are preferably close to each other. The transmitter is fast, and the receiver is slow such that the response time of the receiver exceeds at least the shortest of the durations of the optical pulses. Then the receiver effectively integrates the optical signal and generates the electric signal having a larger amplitude when the optical signal has a larger duration. Thus, the method converts the modulation in pulse duration into the modulation in signal amplitude. In different embodiments of the present invention, the transmitter can be realized by a light-emitting diode, superluminescent light-emitting diode, or a diode laser. The receiver can be realized by a p-i-n diode, by a resonant cavity photodetector, or by an avalanche photodiode.

An optical connecting apparatus has a light source outputting an optical signal indicating a plurality of wavelengths which correspond to a plurality of transmission channels, an optical transmit section and an optical receive section being mounted with integrated circuits and being connected to each other through an optical line of a single system, and a signal conversion section being inlet in the optical line and converting a phase modulated signal into an intensity modulated signal. The optical transmit section includes: a demultiplexer which separates the optical signal from the light source according to the transmission channels; an optical modulator unit which generates phase modulated signals by implementing phase modulation with optical signals from the demultiplexer by using a plurality of optical modulators whose operations are synchronized by a signal from the integrated circuit; and a multiplexer which multiplexes the phase modulated signals from the optical modulator unit and outputs the multiplexed phase modulated signals to the signal conversion section through the optical line. The optical receive section includes: a demultiplexer which separates the intensity modulated signal from the signal conversion section according to the transmission channels; and an optical receiver unit which converts the intensity modulated signals from the demultiplexer into electric signals.

An all-optical converter (10) for converting an intensity-modulated optical signal into an optical signal modulated to the DPSK format, includes a first input (152a) for a first intensity-modulated optical signal (12), a differential encoding module (100) adapted to perform a differential encoding between the first signal (12) and a second optical signal synchronous with the first signal (12), a device adapted to modulate (200) the phase of an optical signal (16) according to the differential encoding performed by the differential encoding module (100), and an output (162c) of the device adapted to modulate (200) delivering an optical signal modulated to the DPSK format (14).

The invention provides an all-optical serial-parallel conversion system based on a wavelength division multiplexing technology. Multi-wavelength light is combined and shunted through the wavelength division multiplexing technology, conversion from a high-speed serial-parallel signal to a low-speed parallel signal is achieved by controlling on-off of a high-speed optical switch, a low-speed parallel non-return-to-zero code electric signal is obtained based on the code pattern conversion technology, and picosecond-magnitude all-optical serial-parallel conversion is achieved. The control signal characteristics and the switching speed of the optical switch are controlled; the all-optical serial-to-parallel conversion with a transparent code pattern is realized, the all-optical serial-to-parallel conversion without cache is realized, the time domain delay of a wavelength division multiplexing optical signal is realized by utilizing the dispersion time domain dispersion delay characteristic,the serial-to-parallel conversion is carried out through the high-speed optical switch switching unit, and a non-return-to-zero code electric signal is obtained through the code pattern conversion unit.

The invention discloses an integrated optical module error code tester based on PAM4. The integrated optical module error code tester comprises a main control unit, an interface unit and an upper computer. By integrating peripheral circuits such as a communication interface, a power supply circuit, an I / O interface and the like into a main control unit, the SoC performs power supply configurationand I / O signal definition according to different optical module types. The interface unit is connected with the main control unit through the pluggable connector, only the interface unit needs to be replaced when different optical module tests are carried out, and corresponding peripheral circuits do not need to be customized. The optical module interface circuit and the error code test module areboth integrated in the interface unit, and no cable is needed for connection, so that the loss in the test process is reduced, and NRZ / PAM4 signals with higher rate and PRBS code patterns with longerlength can be tested.

The invention relates to an all-optical converter for converting an intensity modulated optical signal into an optical DPSK modulated signal comprising a first input for a first intensity modulated optical signal, a differential encoding module for carrying out a differential encoding between the first signal and a second optical signal synchronous therewith, a device for modulating the phase of an optical signal according to the differential encoding which is carried out by the differential encoding module and the output of the modulating device delivering the optical DPSK modulated signal.