16 results about "Directly modulated laser" patented technology

The invention relates to the technical field of photoelectronics, and discloses a chirp parameter measuring device and method based on a directly modulated laser optical module, and the device comprises an arbitrary waveform generator, an optical module, a tunable dispersion compensation module, and an oscilloscope. The optical module comprises a directly modulated laser; the output of the arbitrary waveform generator is electrically connected with the radio frequency input port of the directly modulated laser; the output optical signal end of the directly modulated laser is connected with the input optical end of the adjustable dispersion compensation module; the adjustable dispersion compensation module is used for controlling dynamic switching between a zero dispersion state and a preset non-zero dispersion state by introducing dispersion into a link, and an output optical signal port of the adjustable dispersion compensation module is optically connected with a receiving port of the optical module; and the radio frequency output end of the optical module is electrically connected with the oscilloscope. According to the invention, the problems of long chirp parameter test time and high measurement cost in the prior art are solved, and the chirp parameter measurement method has the characteristic of being capable of realizing rapid and accurate chirp parameter measurement.

This invention relates to a machine learning-based modeling method for cloud wireless access networks, comprising: acquiring a remote cloud wireless access network transmitter; improving the remote cloud wireless access network transmitter by replacing the traditional microwave source with a dual-ring opto-oscillator to suppress side modes through single-mode oscillation; and introducing a directly modulated laser after an arbitrary waveform generator to utilize the chirp effect and fiber dispersion to generate power gain; and modeling the millimeter-wave signal spectrum of the improved remote cloud wireless access network transmitter based on a lightweight gradient booster model to match the dimensions of input and output features. This invention uses a dual-ring opto-oscillator to replace the traditional microwave source, reducing phase noise; utilizes the synergistic gain behavior of the directly modulated laser chirp and fiber dispersion to improve the transmission gain of the millimeter-wave signal; and models the spectral characteristics of the millimeter-wave signal using a lightweight gradient booster model to achieve spectrum prediction.

A controller stabilizes a distributed feedback plus reflection (DFB+R) laser, which has a back facet, a DFB section, a passive section, and a front facet with a low reflective element. An etalon filter is formed by a portion of the DFB section, the passive section, and the low reflective element. Control circuitry directly modulates the DFB section with a modulation signal and biases the passive section with a bias signal. In operation, a lasing mode of the DFB section is aligned to a long wavelength edge of one of the periodic peaks of a reflection profile of the etalon filter. Meanwhile, photodiodes are arranged to monitor the output power emitted from the laser's front and back facets. The control circuitry monitors a ratio of the detected output power and adjusts the bias based on the monitored ratio.

A laser includes a substrate, a first cladding and a second cladding, a gain medium, and a plurality of supports. The first cladding is spaced apart from the substrate by an air gap. The first cladding has a thickness in a vertical direction in a range from 0.05 microns to 0.15 microns. The gain medium is disposed on the first cladding opposite the air gap. The second cladding is disposed on the gain medium opposite the first cladding. The second cladding has a thickness in the vertical direction in a range from 0.05 microns to 0.15 microns. The supports are coupled to each of the substrate, the first cladding, the gain medium, and the second cladding to hold the first cladding, the gain medium, and the second cladding spaced apart from the substrate.

An H-bridge integrated laser driver optimizes power consumption, impedance matching, low-swing and high-swing reliability for electro-absorption modulated laser (EML) and direct modulated laser diode (DML) applications, VCSEL / silicon photonics, and other applications requiring high-swing drivers or control of impedance. The laser driver includes a retimer for converting low-speed parallel data into a high-speed serial bit stream and an inverted representation of the high-speed parallel bit stream, an M-bit PMOS DAC configured to receive a first buffered bit stream, an N-bit NMOS DAC configured to receive a second buffered bit stream substantially synchronized with the first buffered bit stream. A protection device is coupled between the M-bit DAC and the N-bit DAC. A first DC level shift pre-driver array is coupled between the retimer and the M-bit DAC to receive the high-speed parallel bit stream and the inverted high-speed parallel bit stream, and a second DC level shift pre-driver array is coupled between the retimer and the N-bit DAC to receive the high-speed parallel bit stream and the inverted high-speed parallel bit stream. An impedance matching module is coupled to an output of the protection device. The laser driver can be integrated on a CMOS communication chip.

The invention provides a directly modulated laser, which comprises a substrate, an epitaxial layer, a buffer layer, a grating layer, a lower limiting layer, an active layer, an upper limiting layer, a corrosion cut-off layer, a cladding and a contact layer, the structure of the grating layer is a convex grating structure with a lambda / 8 phase shift, the grating layer is located on the N-type doped side, and the convex grating structure with the lambda / 8 phase shift is used for reducing the photon density at the phase shift position through the negative reflector loss feedback effect and limiting hole gathering on the P-type doped side through the characteristic that the electron mobility is larger than the hole mobility.

A transmitting apparatus includes a direct modulation laser, a branching unit, a first signal generation unit, a second signal generation unit, and a polarized wave multiplexing unit. The branching unit branches continuous phase frequency shift keying signal light having been generated by the direct modulation laser by applying a first modulation signal into first branch light and second branch light. The first signal generation unit generates first polarized wave signal light obtained by removing an intensity modulation component having been generated by the direct modulation laser by applying the first modulation signal from the first branch light. The second signal generation unit generates second polarized wave signal light obtained by removing the intensity modulation component from the second branch light and adding an intensity modulation component to the second branch light by applying a second modulation signal, the second polarized wave being orthogonal to the first polarized wave. The polarized wave multiplexing unit multiplexes the signal light for the first polarized wave and the signal light for the second polarized wave.

The invention relates to a cloud wireless access network modeling method based on machine learning, and the method comprises the steps: obtaining a remote cloud wireless access network transmitter, improving the remote cloud wireless access network transmitter, replacing a conventional microwave source of the remote cloud wireless access network transmitter with a double-ring photoelectric oscillator, and suppressing a side mode through single-mode oscillation, a direct modulation laser is introduced behind the arbitrary waveform generator and is used for generating power gain by utilizing a chirp effect and optical fiber dispersion cooperative gain; and based on a lightweight gradient elevator model, modeling a millimeter wave signal spectrum of the improved remote cloud wireless access network transmitter, and matching input feature dimensions and output feature dimensions. According to the invention, the dual-ring photoelectric oscillator is adopted to replace a traditional microwave source, so that phase noise is reduced; a cooperative gain behavior of directly modulating laser chirp and optical fiber dispersion is utilized to improve millimeter wave signal transmission gain; the spectral characteristics of millimeter wave signals are modeled through a lightweight gradient elevator model, and spectrum prediction is realized.

A communication system is provided with: a direct modulation laser that outputs an optical signal carrying information to be delivered; an injection circuit that injects a current into the direct modulation laser; a control unit that controls an operation of the direct modulation laser by controlling an operation of the injection circuit; and a reception device that receives the optical signal. The direct modulation laser is provided with: a laser active region of a distributed feedback type; and an optical feedback region that is optically connected to one end, in a waveguide direction, of the laser active region and that has an optical waveguide structure in which a reflection point is formed in the waveguide direction. The control unit causes the direct modulation laser to operate under a plurality of predetermined mutually-different conditions, and causes the direct modulation laser to output the optical signal for conveying the information under each of the conditions.

A dual output directly modulated laser device is provided that generates two distinct optical output signals. The dual output directly modulated laser device includes two outer gain sections, each directly modulated by injection of a respective modulation current. The dual output directly modulated laser device further includes a central section including a distributed reflector providing optical feedback to both outer gain sections while preventing the generation of stimulated photons. The two outer gain sections form two laser cavities each configured to emit a directly modulated signal as an optical output signal in a direction away from the central section. The dual output directly modulated laser device can simultaneously be used for main-PON upstream and sub-PON downstream transmission, thus, with this enhanced functionality, the laser device makes a passive optical network architecture more energy efficient by reducing power consumption and implementation cost as well.

A drive circuit for a direct modulated laser and a direct modulated optical transmitter. The drive circuit includes a service data drive unit, a voltage configuration unit, a monitoring data modulation unit, and a monitoring current generation unit. Output terminals of the voltage configuration unit and the monitoring data modulation unit are connected to a same input terminal of the monitoring current generation unit. An output terminal of the service data drive unit is connected to a current sink interface of the monitoring current generation unit, and is suitable for connecting a direct modulated laser. In the technical solution, a low-speed monitoring data signal is mixed into an average optical power signal of a high-speed service data light wave from the direct modulated laser, then is extracted from the received optical signal by a remote optical receiver, enabling the drive circuit to be remotely monitored.

Systems may include one or more directly modulated laser (“DML”) optical transmitters to transmit optical signals carrying data to one or more optical receivers and include one or more filters designed to reduce the power in lower modulation levels. In various embodiments, the optical receiver includes an optical combiner to combine local oscillator light at a frequency, fLO with the optical data signal, an optical-electrical converter to downconvert the combined LO-optical signal to an electrical signal including four PAM4 frequencies, an electrical filter to attenuate the electrical power in the PAM4 frequencies by differing amounts, rectify and output the electrical signal. Systems may include extinction ratio management and thermal chirp compensation, and may include optical filters designed for chirp management with different laser parameters (α and k) and OMAs with PAM-M format in both optical and electrical domains and for use with quasi-coherent receivers (QCR) and DML transmitters.

The present application discloses a directly modulated laser array chip and a method for manufacturing the same, relating to the technical field of semiconductor laser manufacturing. The directly modulated laser array chip is provided with at least two input paths and one output path. All input paths are coupled together into one output path to form a laser array. Each input path is provided with a laser unit and a grating structure capable of forming an equivalent FP feedback cavity therewith. The grating structures are formed by etching a grating material according to a predetermined pattern, and the etching passes through the grating structure and extends into the underlying spacer layer. The technical solution of the present application can introduce an optical-optical resonance effect into the laser array while obtaining multiple grating structures with different reflectivities in a single etching process by combining electron beam exposure and dry etching, thereby reducing the process complexity of chip manufacturing.

The invention discloses a nonlinear distortion suppression method and device for an optical single-side-band transmitter based on an electro-absorption modulated laser. A digital pre-distortion model containing second-order nonlinearity and intermodulation distortion of a direct modulated laser and an electro-absorption modulator is established in a digital domain; and a cost function is constructed in combination with an actual output spectrum, and a model coefficient is adaptively iteratively updated, so that the optical single-side band signal output by the transmitting end realizes forward compensation on a main nonlinear component before transmission, and the transmission efficiency is improved on the premise that an additional optical device and a complex receiving end balance structure are not required to be increased. According to the optical single-side-band transmitter, nonlinear distortion and intermodulation distortion caused by cascade modulation are effectively suppressed, the linearity and the adjacent channel power ratio of the optical single-side-band signal are remarkably improved, the signal-to-noise ratio and the bit error rate performance of the system are improved, and the transmission capacity and the engineering practicability of the optical single-side-band transmitter in a medium-long-distance high-speed optical interconnection scene are enhanced.

The invention discloses a laser radar signal generation method, a laser radar signal detection method and a laser radar signal detection system. The system comprises a transmitting end and a receiving end, the transmitting end comprises a transmitting end modulation module used for generating a first electric driving signal and a target modulation reference signal; the direct modulation module directly modulates the first electric driving signal to generate a calibration electric signal; the pre-distortion equalization module compares the calibration electric signal with the modulation reference signal to generate a second electric driving signal; the beam transmitting module adopts a second electric driving signal to drive a direct modulation laser to generate radar detection signal light to be transmitted; the receiving end comprises a beam receiving module used for receiving reflected signal light after the radar detection signal light is reflected by a target; the coherent detection module performs coherent mixing on the reflected signal light and the transmitted signal light to obtain an electric signal; the phase recovery module obtains a signal after phase recovery according to the electric signal; the distance analysis module estimates the distance of the target; the Doppler processing module estimates a relative velocity of the target.