93results about How to "Improved wavelength stability" patented technology

An optical lasing device, comprising (i) a lasing medium disposed in a lasing cavity, (ii) an etalon disposed within the lasing cavity, and (iii) an electrically tuned filter device, such as a grating waveguide structure device. The lasing device also comprises a detector for determining the lasing power of the lasing device, and a controllable phase shift capability, and the device is preferably locked to a maximum of the lasing power by adjusting the phase, thereby achieving locking to a wavelength predetermined by the etalon, aligned to an ITU grid wavelength. Adjusting the phase shift to achieve the maximum of the lasing power is preferably performed using a closed loop system. Furthermore, adjusting of the phase shift to achieve a maximum of the lasing power is preferably also operative to wave lock the lasing device to a peak wavelength of the etalon.

Optical pump modules comprising VCSEL and VCSEL array devices provide high optical power for configuring fiber optic gain systems such as fiber laser and fiber amplifier particularly suited for high power operation. Pump modules may be constructed using two reflector or three reflector VCSEL devices optionally integrated with microlens arrays and other optical components, to couple high power pump beams to a fiber output port. The pump module having a fiber output port is particularly suited to couple light to an inner cladding of a double-clad fiber, often used to configure high power fiber laser and fiber amplifier. The pump modules may be operated in CW, QCW and pulse modes to configure fiber lasers and amplifiers using single end, dual end, and regenerative optical pumping modes. Multiple-pumps may be combined to increase pump power in a modular fashion without significant distortion to signal, particularly for short pulse operation.

The invention provides a laser frequency stabilization realization method. The laser frequency stabilization realization method comprises steps that: step 1, a single-block dual-wavelength laser device is utilized to output 532nm laser; step 2, an iodine saturation absorption frequency stabilization device is utilized to carry out determination processing on the 532nm laser, if a frequency of the 532nm laser deviates from a reference frequency of the iodine saturation absorption frequency stabilization device, a feedback signal is generated by the iodine saturation absorption frequency stabilization device and is sent to a servo control device, and a step 3 is carried out; if the frequency of the 532nm laser is in the reference frequency of the iodine saturation absorption frequency stabilization device, laser frequency stabilization is realized, and no processing is needed; and step 3, chamber length of the single-block dual-wavelength laser device is adjusted by utilizing the servo control device according to the feedback signal, and the frequency of the 532nm laser is made to be in the reference frequency. The laser frequency stabilization realization method greatly improves stability and reproducibility of the frequency of the laser device.

A surface emitting semiconductor laser (10) is shown having a semiconductor lasing structure having an active layer (22), opposed cladding layers contiguous to said active layer, a substrate (17), and electrodes (12,14) by which current can be injected into the semiconductor lasing structure. Also included is a second or higher order distributed diffraction grating (24) having periodically alternating elements, each of the elements being characterized as being either a high gain element (26) or a low gain element (28). Each of the elements has a length, the length of the high gain element and the length of the low gain element together defining a grating period, where the grating period is in the range required to produce an optical signal in the optical telecommunications signal band. The total length of the high gain elements is no more than the total the lengths of the low gain elements. A single laser structure may be provided or an array of side by side laser structures on a common substrate is also provided. In a further aspect a method of testing laser structures on wafer is provided.

Fiber optic gyroscope architectures that incorporate both (i) a WDM-based wavelength control and (ii) a wavelength reference based on a narrowband fiber Bragg grating (FBG), with the latter component providing significant improvement in the stability of the wavelength reference by calibrating out wavelength errors associated with a WDM-based wavelength control scheme.

A periodically poled second harmonic generating crystal having a long axis, said crystal comprising Magnesium Oxide doped Congruent Lithium Niobate, Magnesium Oxide doped Stoichiometric Lithium Niobate, Stoichiometric Lithium Tantalate or Potassium Titanyl Phosphate wherein the poling planes of said periodically poled crystal are canted relative to said axis and a doubled, external cavity laser utilizing said crystal, comprising an external cavity pump laser section and an extra-cavity frequency doubling section.

An optical module has a hermetically sealed package, a semiconductor laser element located within the package for outputting a laser beam, an optical fiber for receiving and externally delivering the laser beam outputted from the front end face of the semiconductor laser element, a prism for receiving a monitoring laser beam outputted from the back end face of the semiconductor laser element and for dividing the received laser beam into two laser beam components which are inclined relative to the optical axis with predetermined angles less than 90 degrees, a first photodiode for receiving one of the laser beam components divided by the prism, a second photodiode for receiving the other laser beam component from the prism, an optical filter disposed between the first photodiode and the prism and adapted to permit only a laser beam having a predetermined wavelength range to pass therethrough, and a PD carrier in which the first and second photodiodes are mounted on the same mount surface.

A method of controlling a semiconductor laser that has a plurality of wavelength selection portions having a different wavelength property from each other and is mounted on a temperature control device, including: a first step of correcting a temperature of the temperature control device according to a detected output wavelength of the semiconductor laser; and a second step of controlling at least one of the wavelength selection portions so that changing amount differentials between each wavelength property of the plurality of the wavelength selection portions is reduced, the changing amount differential being caused by correcting the temperature of the temperature control device.

A semiconductive laser module according to the present invention is configured with a semiconductive laser module having a semiconductive laser device, a cavity formed with at least one light feedback means included, and an optical fiber located at a front side of the cavity, wherein an optical filter for transmitting light of wavelength within a predetermined range is disposed in the cavity. The above-noted semiconductive laser module additionally has a combination of a collimator and a focusing lens for coupling emitted light from the semiconductive laser device with the optical fiber, and the optical filter is disposed between the collimator and the focusing lens. The optical filter has a dielectric multi-layered filter for transmitting a desired wavelength. A laser unit according to the present invention is configured with a plurality of semiconductive laser modules as noted above, and a polarization combiner for making a polarization combination of emitted light from the plurality of semiconductive laser modules. A Raman amplifier according to the present invention has a pumping light source configured with the semiconductive laser module or the laser unit.

A laser interferometric measuring instrument includes: a light source that emits a laser beam of 1064 nm and another laser beam of 532 nm; a polarizing beam splitter; a dichroic mirror that splits a long-wavelength laser beam provided in a measurement optical path; a long-wavelength corner cube that reflects the split laser beam; a measurement corner cube that is displaceable along the measurement optical path; a reference corner cube that is displaceable along a reference optical path; a optical path changing unit that changes an optical path length of the long-wavelength laser beam; a phase detector that outputs interference signals; a sum signal computer that calculates a sum signal; a displacement controller that displaces the reference corner cube so as not to change a phase of the sum signal; a reference displacement detector that detects a displacement of the reference corner cube; and a measurement displacement computer that calculates a displacement of the measurement corner cube.

Structure of the disclosed fiber laser in single longitudinal mode including a DFB fiber laser is as following: two ends of DFB fiber laser are fixed on a thin metal plate through ultraviolet silica gel; the metal plate is placed on semiconductive ceramic chip, and a layer of conductive silica gel is between the metal plate and ceramic chip; the semiconductive ceramic chip is placed on a cooling plate; through a thermal resistor, the metal plate is connected to control pole of temperature control power source; through two pieces of conducting wire, two ends of the semiconductive ceramic chip are connected to two poles of temperature control power source. Except temperature control power source, each part said above is packaged in a thermal shield. Through a wavelength division multiplexer (WDM), one end of DFB fiber laser is extended out the shield to connect to a laser pump. Through a fiber optic isolater, third end of WDM constitutes output end of the disclosed laser.

The invention discloses a silicon-based tunable laser, and relates to the field of silicon-based photonics and integrated optoelectronics. The silicon-based tunable laser includes a semiconductor amplifier integrated on a silicon-based platform, a spot-size converter which is connected to a backlight end of the semiconductor amplifier and includes a double inverted cone waveguide, an asymmetric Mach-Zehnder interferometer (AMZI) which includes a first arm and a second arm of unequal length, wherein input ends of the first arm and the second arm are cascaded with the double inverted cone waveguide, output ends of the first arm and the second arm intersect to form a single waveguide and a heater is arranged on the second arm, a first micro-ring filter which is cascaded with the first arm andprovided with heaters, a second micro-ring filter which is cascaded with the second arm and provided with heaters, and a distributed Bragg reflector (DBR) which is used for realizing optical feedbackand formed on the single waveguide. The silicon-based tunable laser has the advantages of low manufacturing cost, simple process and high integration, benefits large-scale production, and can improvetuning bandwidth and wavelength stability.

The present invention discloses a Fiber Bragg Grating demodulation device with a suppressed fluctuation at a variable ambient temperature and a demodulation method. The device comprises a broadband light source (1), an optical attenuator (2), a tunable F-P filter (3), a first optical fiber isolator (41), an erbium-doped optical fiber amplifier (5), an optical fiber first-stage beam splitter (6), a first optical fiber second-stage beam splitter (71), optical fiber circulators (8), FBG sensor arrays (9), a first photoelectric detector array (161), an optical fiber gas cell (10), a second optical fiber second-stage beam splitter (72), an optical fiber F-P etalon (11), a notch filter (12), an optical fiber assisted interferometer (13), a data acquisition card (17) and a processor (18).

A highly stable broadband light source includes a semiconductor light source having a specific emission spectrum, an optical filter having a specific bandpass filtering function and a predetermined bandwidth and a coupling element, to which the light emissions of the semiconductor light source and of the optical filter are fed. The light emission of the broadband light source occurs at the output of the coupling element. The spectrum of the light emission of the broadband light source is composed of the emission spectrum of the semiconductor light source and the bandpass filtering function of the optical filter. The wavelength of the optical filter is temperature-stabilized so that the spectrum of light emission of the broadband light source is essentially determined solely by the filtering function of the optical filter.

Disclosed is a semiconductor laser module which is advantageous as a pumping source for Raman amplification because of its high optical output and excellent wavelength stability. The module comprises a Fabry-Pérot semiconductor laser device to which a fiber Bragg grating having a wavelength selectivity and showing a specific reflectivity with respect to a specific wavelength is optically coupled, wherein given that a cavity length of the semiconductor laser device is L ( mu m), a reflection bandwidth of the fiber Bragg grating is DELTA lambda (nm) and a reflectivity of said front facet is R1 (%) and a peak reflectivity of said optical feedback part is R2 (%), following equations are satisfied among L, R1 and R2 1000 mu m ≤ L ≤ 3500 mu m, 0.01% ≤ R1 + c<2>R2 ≤ 4% and R1 / R2 ≤ 0.8 where c represents a coupling efficiency between the semiconductor laser device and the fiber Bragg grating. It is preferable that 0.2 nm ≤ DELTA lambda ≤ 3 nm should be satisfied. <IMAGE>

The multiple wavelength ultra continuous light source of dense wavelength division multiplexing belongs to optical communication area. Two fiber-coupler forms loop type cavity. Continuous light output from semiconductor laser through connection of 50:50 fiber coupler is input to phase modulator. Connection sequence is as following: from radio frequency microwave source to phase modulator, dispersed fiber, powerful erbium doping amplifier, dispersion displacement optical fiber, 90:10 fiber coupler. 90% output port is connected to another input port of 50:50 fiber couplers. 10% port is connected to one end of erbium doping fiber amplifier, and another end of the erbium doping fiber amplifier is input to demultiplexer. The invention through modulation generates stable shorter light wavelength with lower injected optical power.

The invention discloses a wide-spectrum light source for a fiber-optic gyroscope and a manufacturing method of the wide-spectrum light source. The light source can be an L-wave-band light source or a C+L-wave-band light source. Both the L-wave-band light source structure and the C-wave-band light source structure comprise pump lasers, optical fiber wavelength division multiplexers, er-doped optical fibers, optical fiber isolators and optical fiber reflectors. The C-wave-band light source structure is similar to the L-wave-band light source structure. The L-wave-band light source or the C+L-wave-band light source can be cascaded through a 1*3 optical fiber coupler. According to the wide-spectrum light source for the fiber-optic gyroscope and the manufacturing method of the wide-spectrum light source, a full-optical-fiber device is adopted, the wide-spectrum light source is easy to manufacture, miniaturization is facilitated and the wide-spectrum light source has the advantages of being wide in spectrum of the light source, high in power output, good in stability of wavelength, free of polarized radiation, not sensitive to ultraviolet ray, low in cost, long in service life and the like.

A position-measuring device, for ascertaining the position of two objects which are disposed in a manner allowing movement relative to each other in at least one measuring direction, includes a light source, as well as a splitting device by which a light beam, provided by the light source, is split into two or more partial beams of rays. The partial beams of rays traverse at least two partial-beam paths. Interfering partial beams of rays from the partial-beam paths strike a plurality of opto-electronic detector elements, so that displacement-dependent position signals are ascertainable via the detector elements. The light source takes the form of a semiconductor laser having a fiber-grating feedback device.

A hybrid external cavity laser (HECL) system comprises a diode laser, collection and collimation optics, and a volume Bragg grating, emits radiation at a single wavelength with a short-term wavelength stability in the order of at least one part in a billion The wavelength stability is achieved by use of a thermal management system, comprising inner and outer housings, each containing a temperature sensor, and electronic circuitry that monitors the temperatures and controls both the laser diode current and a thermoelectric cooler based on temperatures determined from said temperature sensors. The laser system is packaged in a compact enclosure that minimizes waste heat, facilitating use in applications that have heretofore employed stable, single-frequency lasers, including He—Ne lasers.

A hybrid external cavity laser and a method for configuring the laser having a stabilized wavelength is disclosed. The laser comprises a semiconductor gain section and a volume Bragg grating, wherein a laser emission from the semiconductor gain section is based on a combination of a reflectivity of a front facet of the semiconductor gain section and a reflectivity of the volume Bragg grating and the reflectivity of the semiconductor gain section and the volume Bragg grating are insufficient by themselves to support the laser emission. The hybrid cavity laser further comprises an etalon that provides further wavelength stability.

Characters of the method are: monochromatic light needed in measurement is obtained by adopting LEDs possessing different centered wavelengths; measuring device includes measuring light intensity and referencing light intensity generated from wide spectrum photosensors having same characteristics of spectral response; at different moment, driving different LEDs obtains values of spectral response corresponding to relevant central wavelength in order to obtain spectrum response curve further. The invention is applicable to measuring situation: inexact requirement on wavelength resolution; not need of measurement in continuous wavelength; characters of object to be measured are not changed or changed slowly, suitable to production in industrialization scale.

Particular embodiments of the present invention relate generally to a method of fabricating a wavelength conversion device. According to the method, the wavelength conversion device is fabricated by providing a nonlinear optical material and poling the nonlinear optical material to form a plurality of periodically inverted poling domains arranged at an anti-back reflective periodicity Λ. The geometry and the anti-back reflective periodicity Λ of the poled nonlinear material are selected such that the difference between a phase matching wavelength λΦ of the poled nonlinear optical material and a Bragg wavelength λBRAGG of the poled nonlinear optical material is greater than 1 nm.

The invention provides a super-fluorescence optical fiber light source and a method for generating super-fluorescence. The super-fluorescence optical fiber light source comprises a plurality of laser diode (LD) pump sources, a plurality of LD driving power supplies, a pump beam combiner and a gain medium, wherein the LD pump sources are used for outputting laser; the working temperature range of the super-fluorescence optical fiber light source is divided into a plurality of working temperature areas; pump wavelength which is output by each LD pump source is matched with one of the working temperature areas; a plurality of LD driving power supplies respectively supply current to a plurality of LD pump sources; the pump beam combiner is connected with an output end of each LD pump source and used for coupling the output laser and injecting the output laser into the gain medium; the gain medium is used for absorbing the laser which is injected by the pump beam combiner to excite generation and amplification of the super-fluorescence; and part of the amplified super-fluorescence is coupled by the pump beam combiner and then output. In a temperature area switching type pump mode, influence of environment temperature change on the pump wavelength and pump power of each LD pump source is reduced, and severe requirements for temperature control of the LD pump sources are greatly reduced.