16 results about "Threshold current" patented technology

The embodiment of the application provides a test method, network equipment and an optical module, relates to the technical field of optical communication, and improves the influence caused by the failure problem of the optical module. The specific scheme is as follows: the network equipment obtains threshold currents of the optical module at different time points in sequence, whenever a threshold current is obtained, the network equipment obtains the aging rate at the current time point based on the obtained threshold current and the aging rate at the previous time point, and the network equipment obtains the life margin of the optical module at the current time point based on the initial threshold current, the obtained threshold current and the aging rate at the current time point, wherein the initial threshold current is obtained according to the temperature at the initial time point of the current test of the optical module and a mapping relationship. The embodiment of the application is used for the process of predicting the life margin of the optical module by the network equipment.

A laser display system 100 is configured to increase the dynamic range of a laser diode by modulating an operating current applied to the laser diode based on a desired sequence of brightness levels and a temperature of the laser diode. In some embodiments, a measuring circuit measures a voltage of the laser diode at a given current, which indirectly indicates the temperature of the laser diode, thus obviating the need for a direct measurement of temperature. In addition, in some embodiments, the measuring circuit identifies a threshold current of the laser diode based on a range of current values at which values of the current multiplied by the derivative of the voltage against the current vary relatively rapidly. By compensating for temperature effects and identifying the threshold current, a driver of the laser diode more precisely controls light output of the laser diode across an increased dynamic range.

The application discloses an anti-interface rough scattering quantum cascade laser active region and a preparation method thereof. The application forms a topological interface state protected by chiral symmetry as a lasing upper energy level at the butt joint interface between a first superlattice region and a second superlattice region, the wave function of the topological interface state is strictly zero in the thick barrier center and the interface, thereby the non-radiation loss caused by the interface roughness scattering is inhibited from the root, and the upper energy level carrier lifetime is significantly prolonged. Based on this, the threshold current density of the quantum cascade laser is greatly reduced, and high-efficiency lasing of 10 μm wavelength can be realized at room temperature. Meanwhile, a mixed epitaxy process combining molecular beam epitaxy and metal organic chemical vapor deposition is adopted, the nanometer precision energy band design of the core active region is ensured, and the efficient growth of the thick film waveguide layer is realized, which is beneficial to the practicalization and large-scale preparation of the device.

The application discloses a single-photon avalanche diode modeling method based on Verilog-A, which comprises the following steps: model parameter definition and initialization; judging the state of the single-photon avalanche diode, if the avalanche is closed, performing statistical model calculation, judging whether the avalanche state is opened according to the statistical model calculation result, if the avalanche is opened, performing electrical model calculation, updating the avalanche state according to the electrical model calculation result and the quenching threshold current based on Gaussian distribution, and outputting each current; the statistical model calculation comprises calculating the photon detection event time, the dark count event occurrence time and the post-pulse trigger time; the electrical model calculation comprises calculating the leakage current and the segmented avalanche current, and calculating the junction charge of the SPAD cathode-anode, the parasitic capacitance charge of the SPAD cathode-substrate and the parasitic capacitance charge of the SPAD anode-substrate, so as to calculate the corresponding current according to the charge-current relationship. The application can comprehensively reflect the working characteristics of the device.

Embodiments of the present disclosure provide techniques for optimizing quiescent current in an amplifier. The amplifier may include an output stage associated with a quiescent current; a set of NMOS transistors comprising a first NMOS transistor and a second NMOS transistor connected together. The first NMOS transistor may have a first bias current. The amplifier may further include a first set of PMOS transistors comprising a first PMOS transistor and a second PMOS transistor. The first PMOS transistor may have a second bias current. The amplifier may further include an optimization circuit. The optimization circuit may include a current steering circuit that is driven by a threshold current. The optimization circuit may further include a level shifting device connected to the current steering circuit. The current steering circuit may be configured to adjust the first bias current based on the threshold current.

The embodiment of the invention provides an active alignment assembly method and system for a laser module and related equipment, and aims to improve the repeated assembly precision of an optical lens of the laser module and reduce the hardware cost and the system debugging difficulty. The method provided by the embodiment of the invention comprises the following steps: controlling the driving current of the semiconductor laser chip to be lower than the threshold current of the semiconductor laser chip, so that the semiconductor laser chip is in an incoherent light-emitting mode; light emitted by the semiconductor laser chip in the incoherent light emitting mode is spontaneous radiation incoherent fluorescence and is used for illuminating micro-textures of a light emitting surface of the semiconductor laser chip; a micro texture image of the light-emitting surface of the semiconductor laser chip after conjugate imaging through the optical lens to be assembled is collected through an imaging unit; and adjusting the relative position of the optical lens to be assembled and the semiconductor laser chip according to the detection signal intensity of the micro texture image, and recording the optimal position of the optical lens to be assembled relative to the semiconductor laser chip.

The application provides a buried heterojunction antimonide laser and a preparation method thereof, and belongs to the technical field of lasers. The problems of a relatively high threshold current, a limited transverse restriction of current and light field, and a single heat dissipation path of a conventional ridge waveguide structure are solved. The laser comprises, from bottom to top, N-face metal, a GaSb substrate, a buffer layer, a lower restriction layer, a lower waveguide layer, a quantum well region, an upper waveguide layer, an upper restriction layer, a cover layer and P-face metal. A ridge is arranged between the P-face metal and the restriction layer, and buried layers are arranged on both sides of the ridge. In the application, the active region is completely wrapped from the side by using a wide-bandgap, low-refractive-index, lattice-matched semiconductor material through secondary epitaxy, the physical properties of the material itself are used to achieve better three-dimensional restriction of current and light field, and thus lower threshold current, higher output power, better mode stability and longer device life are obtained.

The present invention relates to the technical field of semiconductors and discloses a side-emitting single-mode laser with a waveguide having an oxidized aperture hole and its manufacturing process, which prepares an oxidized aperture hole as an optically limited waveguide structure of a single-mode laser, wherein the partially insulated oxidized aperture hole limits the current injection window, which leads to a high current injection efficiency and a low leakage current of the device, while at the same time the side walls of the waveguide have lower scattering losses, which leads to a more pronounced suppression of higher modes and promotes the realization of a high-power single-mode laser with extremely low threshold current density.In the present invention, a structure with a surface grating is also introduced, thereby enabling the design of a single-mode laser with a high grating coupling coefficient, wherein the preparation process is simple, reliable and highly reproducible, which avoids complex secondary epitaxy processes, thereby reducing the risk of chamber contamination and promoting the reproducible preparation of high-quality gratings, thus enabling the realization of multi-wavelength arrays.

The application discloses a laser epitaxial structure of a hollow graphene tube grid embedded waveguide structure, wherein a layer of grid structure hollow graphene tube layers are embedded in upper waveguide layers and lower waveguide layers of the laser epitaxial structure, and the grid structure hollow graphene tube layers form composite upper waveguide layers and composite lower waveguide layers, respectively; the grid structure hollow graphene tube comprises a grid slot and a hollow graphene tube filled in the grid slot. The laser epitaxial structure of the application embeds the hollow graphene tube layers with the grid structure characteristics in the upper waveguide layers and the lower waveguide layers of the laser at the same time, forms the hollow graphene tube grid embedded waveguide structure, breaks the mutual restriction relationship between the stress buffering and the light limitation ability of the light field distribution in the physical layer, improves the light beam quality on the basis of ensuring the high output power, reduces the threshold current and the series resistance, and improves the reliability of the laser and prolongs the service life of the laser.

The application belongs to the technical field of electronic devices, and provides an electronic device epitaxial structure optimization design method based on multi-physical field coupling simulation, comprising: constructing a multi-physical field coupling model of a target electronic device, including a carrier transport model and an optical mode solving model, bidirectional coupling between the carrier transport model and the optical mode solving model, obtaining distribution data of carrier concentration in space and distribution data of optical field intensity in space; based on the carrier concentration spatial distribution data and the optical field intensity spatial distribution data, calculating the spatial offset between the peak position of the carrier and the peak position of the optical field, and determining whether the mismatch state of the current epitaxial structure is a trigger state according to the spatial offset; if it is determined to be a trigger state, a mismatch compensation strategy is executed. The problem of low gain efficiency and high threshold current caused by ignoring spatial matching is solved, and the electro-optical conversion efficiency and output power stability of the epitaxial structure are improved.

This invention provides a method for testing the junction temperature of a semiconductor laser, comprising: acquiring the threshold current of the semiconductor laser at a preset temperature; acquiring the first characteristic peak wavelength of the semiconductor laser at multiple different first test temperatures under a first test current condition; acquiring a linear relationship between the first characteristic peak wavelength of the semiconductor laser under the first test current condition and the junction temperature based on all acquired first characteristic peak wavelengths; acquiring the second characteristic peak wavelength of the semiconductor laser at a second test temperature under a second test current condition; and determining the junction temperature corresponding to the second characteristic peak wavelength based on the linear relationship, thereby obtaining the junction temperature of the active region of the semiconductor laser at the second test temperature under the second test current condition. This simplifies the junction temperature testing process for semiconductor lasers, is simple and practical to operate, and provides intuitive, accurate, and highly repeatable test results, thus improving testing accuracy.

A differential amplification system for receiving first and second input signals, and for generating first and second differential output signals, the differential amplification system comprising a differential amplifier configured to receive the first input signal and the second input signal, provide a first output current at a first current channel, and provide a second output current at a second current channel, a cascode stage configured to receive the first and second output currents, and generate the first and second differential output signals, a detector configured to detect when the first output current flowing through the first current channel meets a first condition, and / or detect when the second output current flowing through the second current channel meets a second condition, wherein a current sink stage configured to redirect at least a portion of the first output current and at least a portion of the second output current away from the cascode stage when the first condition is met by the first output current, and / or redirect at least a portion of the first output current and at least a portion of the second output current away from the cascode stage when the second condition is met by the second output current, wherein the first condition is met by the first output current when the first output current falls below a first threshold current value and / or the first output current rises above the first threshold current value, and the second condition is met by the second output current when the second output current falls below a second threshold current value and / or the second output current rises above the second threshold current value.

The application belongs to the field of new energy vehicle electronic control, and particularly relates to a solid-state circuit breaker bidirectional multistage desaturation protection circuit based on multiple diode modulation, which comprises multiple parallelly connected and identically structured grading detection branches, at least a first grading detection branch and a second grading detection branch; the bidirectional multistage desaturation protection circuit realizes grading of protection delay time under different fault currents. For an overcurrent fault with a fast rising speed of fault current, a higher fault detection threshold current and a very short protection delay time are set, so that the fault can be quickly identified and the solid-state circuit breaker can quickly cut off the fault current. For an overload fault with a longer duration but a smaller fault current, multiple lower fault detection threshold currents and longer protection delay times can be set according to the overload bearing capacity of the specific solid-state circuit breaker and the protected load, so as to improve the ability of the solid-state circuit breaker to pass through the overload current under the premise of ensuring safe operation of the solid-state circuit breaker.

The application discloses a kind of based on multi-source state fusion and model prediction feedforward optical module performance control method, comprising: synchronous acquisition driving chip bias voltage signal, thermoelectric cooler operating current signal, thermoelectric cooler temperature signal and backlight monitoring current signal, generate multi-source electric heat signal sequence;With multiple optical modules in the same batch as node, the batch association graph structure is constructed;Multi-source electric heat signal sequence and batch association graph structure are input into graph enhanced long short-term memory network to aggregate cross-module information, obtain laser equivalent junction temperature estimate and threshold current aging rate estimate;Predict optical power deviation by optical performance prediction model;Solve the cooperative compensation trajectory of bias current and thermoelectric cooler temperature, generate bias current compensation sequence and thermoelectric cooler temperature set value correction sequence;Step down to driving circuit and temperature control unit, execute timing cooperative feedforward compensation, effectively improve the optical power consistency in optical module production batch.

This invention discloses a distributed feedback laser chip and its fabrication method, relating to the field of lasers. The fabrication method of the distributed feedback laser includes: forming an initial epitaxial layer on a substrate; etching to form ridges and steps; forming a buried layer on the steps, the buried layer enclosing the active layer and blocking carrier diffusion; forming a cladding layer and a contact layer; forming at least one trench; the trench is located on one side of the ridge and extends into the buried layer; forming a first electrode layer, the first electrode layer covering the contact layer and the trench above the ridge; and forming a second electrode layer. Implementing this invention can reduce the threshold current of the distributed feedback laser chip and improve its electro-optical conversion efficiency. Simultaneously, it reduces the leakage risk of the distributed feedback laser chip and improves its reliability.