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

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.

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.

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.

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.

In each of a plurality of submarine observation apparatus (1 to n), a branching unit (63) branches fixed-wavelength light (λ1) from an incoming wavelength-multiplexed light signal. An observation signal modulating unit (64) modulates the intensity of the branched fixed-wavelength light (λ1) with observation information multiplexed by an observation signal multiplex unit (61). A combining unit (65) combines light signals (λ2) to (λn) passing through the branching unit (63) and the fixed-wavelength light (λ1a) modulated by the observation signal modulating unit (64) into a composite light signal, and outputs it to an optical fiber (12a). Therefore, in each of the plurality of submarine observation apparatus (1 to n), there is no necessity for providing a wavelength-division-multiplexing-transmission optical transmitter which requires high wavelength stability.

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.

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>

An injection-locked laser is disclosed. The injection-locked laser comprises a seed laser, an oscillator into which a certain component of light output from the seed laser is injected as seed laser light, a frequency converter which shifts a frequency of the remaining component of the light output from the seed laser, a photodetector which detects light obtained by synthesizing the light output from the oscillator and the light output from the frequency converter, and a controller which controls an optical path length of the oscillator based on a beat signal component contained in the signal output from the photodetector.

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.

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 packaged transmitter device includes a base member comprising a planar part mounted with a thermoelectric cooler, a transmitter, and a coupling lens assembly, and an assembling part connected to one side of the planar part. The device further includes a circuit board bended to have a first end region and a second end region being raised to a higher level. The first end region disposed on a top surface of the planar part includes multiple electrical connection patches respectively connected to the thermoelectric and the transmitter. The second end region includes an electrical port for external connection. Additionally, the device includes a cover member disposed over the planar part. Furthermore, the device includes a cylindrical member installed to the assembling part for enclosing an isolator aligned to the coupling lens assembly along its axis and connected to a fiber to couple optical signal from the transmitter to the fiber.

An external resonator-type light emitting device includes a light source oscillating a semiconductor laser light and a grating device providing an external resonator with the light source. The light source includes an active layer oscillating the semiconductor laser light. The grating device includes an optical waveguide having an incident face to which the semiconductor laser is incident and an emitting face of emitting an emitting light of a desired wavelength, a Bragg grating formed in the optical waveguide, and a propagating portion provided between the incident face and the Bragg grating. Formulas (1) to (4) for the external resonator-type light emitting device are satisfied.

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.