274 results about "Distributed feedback laser" patented technology

A method and system for providing an energy assisted magnetic recording (EAMR) disk drive are described. The EAMR disk drive includes a media, a slider having a trailing face and an air-bearing surface (ABS), at least one distributed feedback (DFB) layer and at least one EAMR transducer on the slider. The DFB laser(s) each includes a plurality of quantum wells, a laser coupling grating, at least one reflector, and a cavity in the at least one DFB laser. The DFB laser(s) for providing energy to the media. The EAMR transducer(s) includes at least one waveguide, a write pole, at least one coil for energizing the write pole, at least one grating, and may include a near-field transducer. The grating(s) include a coupling grating for coupling the energy from the at least one DFB laser to the waveguide(s). The waveguide(s) direct the energy from the at least one grating toward the ABS.

Structures including dielectric diffraction gratings. In some embodiments, laser devices include diffraction gratings defined by openings formed in a dielectric material.

The present invention is a tunable semiconductor laser for swept source optical coherence tomography, comprising a semiconductor substrate; a waveguide on top of said substrate with multiple sections of different band gap engineered multiple quantum wells (MQWs); a multiple of distributed feedback (DFB) gratings corresponding to each said band gap engineered MWQs, each DFB having a different Bragg grating period; and anti-reflection (AR) coating deposited on at least the laser emission facet of the laser to suppress the resonance of Fabry-Perot cavity modes. Each DFB MQWs section can be activated and tuned to lase across a fraction of the overall bandwidth as is achievable for a single DFB laser and all sections can be sequentially activated and tuned so as to collectively cover a broad bandwidth, or simultaneously activated and tuned to enable a tunable multi-wavelength laser. The laser hence can emit either a single lasing wavelength or a multiple of lasing wavelengths and is very suitable for swept-source OCT applications.

A structure using integrated optical elements is comprised of a substrate, a buffer layer grown on the substrate, one or more first patterned layers deposited on top of the buffer layer, wherein each of the first patterned layers is comprised of a bottom lateral epitaxial overgrowth (LEO) mask layer and a LEO nitride layer filling holes in the bottom LEO mask layer, one or more active layers formed on the first patterned layers, and one or more second patterned layers deposited on top of the active layer, wherein each of the second patterned layers is comprised of a top LEO mask layer and a LEO nitride layer filling holes in the top LEO mask layer, wherein the top and/or bottom LEO mask layers act as a mirror, optical confinement layer, grating, wavelength selective element, beam shaping element or beam directing element for the active layers.

Provided are a dual mode semiconductor laser and a terahertz wave apparatus using the same. The dual mode semiconductor laser includes a distributed feedback laser structure section including a first diffraction grating on a substrate and a distributed Bragg reflector laser structure section including a second diffraction grating on the substrate. A first wavelength oscillated by the distributed feedback laser structure section and a second wavelength oscillated by the distributed Bragg reflector laser structure section are different from each other, and the distributed feedback laser structure section and the distributed Bragg reflector laser structure section share the same gain medium with each other.

A two-dimensional photonic crystal coupler is disclosed, together with a cross-coupled laser structure that is based on a two-dimensional photonic crystal coupler stage. Unlike traditional grating couplers, this two-dimensional photonic crystal coupler can couple light into a single or a plurality of discrete directions in the far-field, i.e., the output light may be unidirectional or discrete. The coupler can be integrated with one-dimensional lasers, a distributed feedback laser, a distributed Bragg reflector laser, and integrated on the same waveguide as the lasers. A resonant cavity coupler design improves the coupling efficiency of two-dimensional photonic crystal-based couplers.

Provided are a frequency tunable terahertz transceiver and a method of manufacturing a dual wavelength laser. The frequency tunable terahertz transceiver includes: a dual wavelength laser including two distributed feedback lasers that are manufactured in one substrate and output optical signals of respectively different wavelengths; and an optical device receiving the outputted optical signals to generate a terahertz wave.

A dynamic optical tag system and method that allows for operation over a wide temperature range. A variable wavelength optical source, such as a dual wavelength fiber laser, is generated by combining the outputs from two distributed feedback lasers having separate operating wavelengths using a wavelength division multiplexer (WDM). A quantum well optical modulator mounted on the front surface of a retro-reflector in the remote receiver end of the communication link is biased to modulate one of the two laser wavelengths. At higher temperatures, the optical modulator can be biased to operate at the wavelength of one of the two lasers. At a lower temperature, the optical modulator can be biased to operate at the second of the two wavelengths. The DC bias required to tune the optical modulator is reduced by operating at two separate wavelengths depending on temperature.

An optical analyzer and method for measuring optical properties of optical signals utilizes a heterodyne architecture to measure spectral amplitude and phase of a periodically modulated input optical signal, such as an optical signal from a periodically modulated distributed feedback (DFB) laser. The spectral amplitude and phase measurements are derived from a heterodyne signal, which is produced by combining and mixing the input optical signal and a local oscillator (LO) signal. The optical spectrum that is reconstructed from the heterodyne signal includes “inner” spectral peaks that contain phase information of the input optical signal. The inner spectral peaks may be produced by an optical or electrical mixing technique. The spectral phase of the input optical signal is recovered from the inner spectral peaks of the reconstructed optical spectrum.

The invention discloses a narrow-band distributed feedback laser wavelength scanning fiber bragg grating sensing device, which senses and detects external physical quantities in the following way that: the device comprises a current-driven distributed feedback laser controlled by a temperature control circuit; light emitted from the laser enters a sensing fiber bragg grating through an optical isolation unit; the light passing through the fiber bragg grating enters an opto-electric receiving unit and then enters a control analysis unit in a form of electrical signal; the output wavelength of the distributed feedback laser can be regulated by changing a control temperature; and a grating reflection centre wavelength and a corresponding external physical quantity are reckoned according to an extremum output by the opto-electric receiving unit when the output wavelength of the laser is matched with the fiber bragg grating reflection centre wavelength by temperature scanning. Compared with a conventional structure where sensing is realized by performing wavelength demodulation at the output end of the fiber bragg grating with a broadband light source, the narrow-band distributed feedback laser wavelength scanning fiber bragg grating sensing device has the characteristics of great production cost reduction, and miniature and low-cost engineering.

The invention discloses a wavelength drift compensation method for a laser gas analyzer. The wavelength drift compensation method for the laser gas analyzer is mainly used for compensating the central wavelength drift of a distributed feedback laser (DFB). In the method, the absorption peak position of a signal to be tested is detected and the absorption peak offset is fed back to a laser temperature control module, so that the central wavelength drift of the laser can be compensated. A multi-characteristic-point measurement method is adopted, so that the deviation of noises such as optical interference fringes and the like from the monitoring of the laser central wavelength offset can be reduced, the offset of the laser central wavelength can be measured precisely, and the whole system is credible.

The invention discloses a distributed feedback laser array composed of distributed feedback lasers which are arranged in parallel and made on an epitaxial wafer of a same semiconductor. The epitaxial wafer of the semiconductor at least comprises an upper coating layer, an active layer, a spacing layer, a refractive index control layer, a lower coating layer and a substrate. The active layer or the refractive index control layer is internally provided with bragg gratings forming distributed feedback. All layers above the refractive index control layer form upper table-boards of the distributed feedback lasers. The refractive index control layer forms guided wave structures of the distributed feedback lasers, and the widths of the guided wave structures of all the distributed feedback lasers in the array are different. Any distributed feedback laser in the distributed feedback laser array is composed of an upper electrode, an upper table-board, a guided wave structure, a substrate and a lower electrode. Due to the adoption of the guided wave structures with different widths, each distributed feedback laser is provided with the bragg gratings with the same period, and meanwhile, the lasing wavelength has a certain excursion. The array can be used as a multi-wavelength laser and a tunable laser.

The invention provides a distributed feedback laser and a preparation method thereof. The distributed feedback laser comprises the following layers deposited on a substrate from bottom to top: a lower limit layer, a lower waveguide layer, an active region, an upper waveguide layer, an upper limit layer and an ohmic contact layer; the two sides of the middle part of the distributed feedback laser are etched with grooves, and the bottoms of the grooves are formed in any positions between the ohmic contact layer and the active region; and a ridge type waveguide structure is formed between the two grooves in the middle of the distributed feedback laser, and two side faces of the ridge type waveguide structure are provided with distributed feedback gratings. When the distributed feedback laser is used, the times of extension can be reduced, and errors caused by multiple extensions can be avoided.

The invention discloses a manufacturing method for a monolithic integrated device of an electrical absorption modulator and a self-pulsation laser, which comprises the steps of: selecting an indium phosphide substrate; manufacturing a multiple-quantum-well active region on the extension of the indium phosphide substrate; manufacturing a grating on the multiple-quantum-well active region; growing optical limiting layers on the multiple-quantum-well active region and the grating; growing electrical contact layers on the optical limiting layers; manufacturing P-surface electrodes on the electrical contact layers; transversely manufacturing two electrode isolating channels on the P-surface electrodes; installing a first distributing feedback laser of the self-pulsation laser between the two electrode isolating channels; installing a second distributing feedback laser of the self-pulsation laser on one side; installing the electrical absorption modulator on the other side; thinning the substrate; manufacturing N-surface electrodes on the bottom of a whole pipe core; evaporating and plating a high-reflection film on one end of the pipe core; and evaporating and plating an anti-reflection film on the other end to finish the manufacture of the device. The invention reduces the power loss and the manufacturing cost of a ROF (Rate Of Fire) system emitter, and enhances system stability.

The invention discloses an intensity modulation coherent detection system and method based on ASK and DBPSK relating to the coherent detection field. The system comprises a sending end and a receiving end. The first DFB (Distributed Feedback Laser) laser of the sending end sends optical carriers; united modulation is carried out to electric signals by a united modulation unit basing on ASK and DBPSK; an MZM (Mach-Zehnder Modulator) modulator loads the electric signals after united modulation to the optical carriers to obtain polarization signals; the polarization signals are sent to the receiving end; the second DFB laser of the receiving end sends local oscillation light; a coherent receiver carries out coherent receiving to the polarization signals sent by the MZM modulator basing on the local oscillation light; the real parts and imaginary parts of the polarization signals are respectively generated; the polarization signals are converted into digital signals through an ADC (Analog-Digital Converter); digital signal processing is carried out by a DSP (Digital Signal Processor). According to the invention, the cost of the system is reduced; the receiving sensitivity of the system is effectively improved; the spectrum efficiency is remarkably improved; and the power consumption of the system is reduced.

Provided is a multiple distributed feedback laser device which includes a first distributed feedback region, a modulation region, a second distributed feedback region, and an amplification region. An active layer is disposed on the substrate of the first distributed feedback region, the modulation region, the second distributed feedback region, and the amplification region. A first diffraction grating is disposed in the first distributed feedback region to be coupled to the active layer in the first distributed feedback region. A second diffraction grating is disposed in the second distributed feedback region to be coupled to the active layer in the second distributed feedback region. The multiple distributed feedback laser device further includes a first micro heater configured to supply heat to the first diffraction grating and a second micro heater configured to supply heat to the second diffraction grating.

The invention discloses an information treatment device which is mainly used for the generation, demodulation and reception of optical mark information in an optical mark exchange system, wherein the information treatment device comprises a mark generator, a frequency sweeping local oscillation light source and a mark detection and reception part. The frequency sweeping local oscillation light source mainly realizes the coherent detection recognition of a spectrum amplitude code mark via a distributed feedback laser with frequency demodulated through a sawtooth wave function and receives the mark through a balanced detection method. The spectrum amplitude code mark is recognized through the method, thus a recognition unit structure of the traditional spectrum amplitude code mark can be greatly simplified and the receiving quality of marked signals is improved, and the spectral loss of the system can be reduced effectively and the actual operability of the system is improved.

The invention relates to a photoelectric detection system, in particular to a buried optical cable fault point positioning system combining breakpoint detection and vibration detection, which comprises a distributed feedback laser, a narrow-band laser, an optical switch, an acousto-optic modulator, a driver, a circulator, a detected buried optical cable, a photoelectric detector, an acquisition card and a computer, the beneficial effects of the invention are that an optical time domain reflection test technology and a phase-sensitive optical time domain reflection test technology are multiplexed during an optical cable fault point position test; and according to the sequence of optical cable fault point positioning and optical cable vibration position positioning, the buried optical cablefault point positioning is realized by searching the ground position where the ground knocking position and the fault point position coincide.

Concatenated distributed feedback lasers having novel waveguides are disclosed. The waveguides allow for coupling of the laser beam between active and passive waveguide structures and improved device design and output efficiency. Methods of making along with methods of using such devices are also disclosed.