54 results about "Erbium doped fiber lasers" patented technology

The invention relates to an erbium doped fiber laser with multi-wavelength and mode locking functions and convertible working state and a realization method thereof, in particular to a laser which can realize switching conversion between multi-wavelength and mode locking, has adjustable output wavelength position of multi-wavelength, and can stably work at room temperature and a realization method thereof. The laser comprises: a gain amplification unit, a polarization control unit, an output coupling unit, a comb filtering unit, an optical isolation unit and a nonlinear fiber loop mirror. The realization method of the laser includes the following steps: incident polarization state and double refraction are adjusted to lead the nonlinear fiber loop mirror inserted in the cavity of the laser to be in different working states, and the multi-wavelength and mode locking functions of the laser are respectively realized according to the different working conditions of the nonlinear fiber loop mirror. The invention has the advantages of convenient toning, low cost, being capable of realizing the two functions of stable multi-wavelength continuous output and mode locking pulse output, and the like, and can satisfy the demand for multifunctional laser light sources of optical time division multiplex/wavelength division multiplex communication technology.

The present invention is directed to the creation of zones of permanently altered refractive index characteristics in glass waveguiding devices, including optical fibers and optical waveguides pre-existed in a glass substrate. Such zones in which the refractive index has been permanently altered are created in glass using a very high intensity laser beam which is produced by focusing the light output from an ultrafast pulsed laser at a predetermined target region in the glass. The preferred laser is a Ti:Sapphire amplified, frequency-doubled Erbium-doped fiber laser system, providing light pulses of approximately 100 femtosecond duration, each with an energy of between about 1 nanojoule and 1 millijoule, and preferably at a pulse repetition rate of between 500 Hz and 1 GHz. The repetition rate is chosen to deliver pulses faster than the thermal diffusion time over the dimensions of the volume element being modified. This latter process is to accumulate heat to the point of liquefying the material in order to increase material compliance to the femtosecond writing process and increase the subsequent thermal barrier to relaxation of the written structural element and thereby increase the lifetime of the device or structural function. One or more zones of permanently altered refractive index characteristics can be formed in a waveguiding device, such as an optical fiber by utilizing a focused, pulsed, laser light source which generates a focal region having an intensity greater than the threshold for inducing permanent refractive index changes in the device. The focal region is aligned with the device and relative movement between the focal region and the device has the effect of sweeping the focal region across the device in a predetermined path. The result is a zone within the device in which the refractive index characteristics of the device have been permanently altered so as to control amplitude, phase, spatial propagation or polarization states of light within the material.

The invention belongs to the control field of multimode fiber sensing chaotic lasers, and particularly relates to a control system for multimode fiber modulation chaotic laser. The chaotic laser controller comprises an Erbium-doped fiber laser, a circulator, a single-mode-multimode-single-mode fiber structure, an optical detector and an environmental control device, wherein laser generated in the Erbium-doped fiber laser enters the single-mode-multimode-single-mode fiber structure from one end of the circulator, is led out from the other end of the circulator and then enters a resonant cavity of the Erbium-doped fiber laser to become feedback light and generate chaotic laser; the chaotic laser enters the optical detector through a wavelength division multiplexer in the Erbium-doped fiber laser; and the environmental control device is mounted at a multimode fiber in the single-mode-multimode-single-mode fiber structure so as to control the environment outside the multimode fiber. The chaotic laser controller has the characteristics of capabilities of adjusting the wavelength, the intensity and the like of feedback light, convenience in operation, simple structure, low probability of electromagnetic interference, wide wavelength adjustment range and the like.

The invention provides an all-fiber structure laser system capable of generating high-energy femtosecond pulse, aiming at solving the technical problems of low pulse energy and poor stability of the existing erbium-doped fiber laser. The all-fiber structure laser system comprises a ring laser used for generating high-energy pulse and single-mode fibers used for pulse compression, wherein the ring laser comprises a wavelength division multiplexer (WDM), an erbium-doped fiber, a first polarization controller, a polarization dependent isolator (PDI), a second polarization controller and an output coupler which are sequentially connected through the single-mode fibers in a cavity; the input end of the WDM is provided with a pump light source, the output end of the output coupler is connected with single-mode fibers arranged outside the cavity so as to compress high-energy pulse generated in the cavity. The laser system has the advantages of simple structure, low price, good stability and the like in application, in particular compared with the solid laser for generating high-energy femtosecond pulse, the laser system has the advantages of high pumping efficiency, convenient adjustment and the like and is easy to couple with fibers.

The invention discloses an all-fiber structural laser system capable of generating high-energy wave-free split rectangular pulse, which aims to solve the technical problems that the current erbium-doped fiber laser has low pulse energy and poor stability and is difficult to realize rectangular pulse output. The all-fiber structural laser system comprises two wavelength division multiplexers, an erbium-doped fiber, a first polarization controller, a polarization dependent isolator, a second polarization controller and an output coupler connected in turn through an intra-cavity single mode fiber, wherein the input ends of the two wavelength division multiplexers are provided with pumping light sources. The length of the erbium-doped fiber is 10 to 20 meters, the total length of the single mode fiber is 5 to 10 meters, and the whole intra-cavity net dispersion is kept in a large positive value. The all-fiber structural laser system has the advantages of simple structure, low price, good stability and the like on application; and compared with a solid laser for generating high-energy rectangular pulse, the all-fiber structural laser system has the advantages of high pumping efficiency, adjustment convenience, good pulse quality and the like, and is easy for fiber coupling.

In the present invention a Multi-Wavelength Ring Laser Source (MWRLS) design based on Erbium Doped Fiber Laser is provided. A LiNbO₃ modulator is used to extend laser channels and as mode-locking device.

The invention provides a tunable multi-wavelength erbium-doped fiber laser and a method of the tunable multi-wavelength erbium-doped fiber laser. The tunable multi-wavelength erbium-doped fiber laser comprises a tunable pump light source, erbium-doped fibers, polarization controllers, an opto-isolator, a tunable comb filter, a nonlinear fiber loop mirror and an output coupler. Switching of different wavelength intervals and tuning of wave peak positions in each wavelength interval are achieved by adjusting the incident laser polarization state of the M-Z interference filter; adjustment on the wavelength number and the spectral range is achieved by adjusting the working state of the nonlinear fiber loop mirror; the wavelength number is accurately controlled by adjusting the pumping power. The tunable multi-wavelength erbium-doped fiber laser is formed by all optical devices, and is good in compatibility, convenient to tune, low in cost, capable of achieving stable multi-wavelength output at the indoor temperature and capable of meeting the demands of a wavelength division multiplexing system or the optical time division multiplexing communication technology for a multi-wavelength laser source.

The invention relates to a multi-wavelength erbium-doped optical fiber laser based on a parallel non-linear polarization rotation structure, which comprises a pump source, a wavelength-division multiplexer, a erbium-doped optical fiber, a polarization dependent isolator, a first optical coupler, a first polarization controller, a second optical coupler, a second polarization controller, an ordinary single-mode optical fiber and a polarization-maintaining optical fiber; and the structure is based on polarization rotation effect, the polarization controller in a parallel structure is adopted to form the non-linear polarization rotation structure, so that a multi-wavelength narrow-line width optical fiber laser is realized. Compared with other erbium-doped optical fiber lasers, the structure with non-linear polarization rotation effect inhibits mode competition caused by the homogeneous broadening effect of the erbium-doped optical fiber, so that the multi-wavelength laser output is stable; and the multi-wavelength erbium-doped optical fiber laser based on the parallel non-linear polarization rotation structure is in the parallel structure, so that twice of polarized rotation occurs every time when an optical signal runs in a resonator, the utilization rate of the pump source is improved, the quantity and the power of output laser are increased, and the multi-wavelength erbium-doped optical fiber laser based on the parallel non-linear polarization rotation structure has the advantages of compact structure, low cost, stability in work at room temperature and the like.

The invention discloses a femtosecond laser direct-writing FBG array-based erbium-doped fiber laser. The femtosecond laser direct-writing FBG array-based erbium-doped fiber laser comprises a sensing fiber, wherein a wavelength division multiplexer, a C-band erbium-doped fiber, an L-band erbium-doped fiber, a polarization controller, a fiber circulator, a coupler, a pumping source, a spectrograph,an FBG array and a broadband reflecting mirror, wherein the FBG array is fabricated by a femtosecond laser direct-writing single-mode fiber, and three parallel FBG gratings are engraved on a fiber core of the single-mode fiber and are equal in length and different in reflection wavelength. Femtosecond laser is transmitted through a fiber protection layer, fiber Bragg gratings of which direct-writing periods are respectively 538 nanometers, 542 nanometers and 547 nanometers in the single-mode fiber without removing a coating layer are used as frequency selection devices, the C-band erbium-dopedfiber, the L-band erbium-doped fiber, the pumping source, the polarization controller and the broadband all reflecting mirror are combined to form a linear cavity fiber laser, single-wavelength and dual-wavelength laser output of which wavelengths can be switched is achieved, a side mode in a laser spectrum is prevented, and the wavelength stability is improved.

The invention discloses an erbium-doped fiber laser, comprising a wavelength division multiplexing coupler, an erbium-doped gain optical fiber, a first polarization controller, an isolator, a polarizer, an output coupler, a second polarization controller and a pumping source. The output end of the pumping source is connected with the input end of the wavelength division multiplexing coupler, the wavelength division multiplexing coupler, the erbium-doped gain fiber, the first polarization controller, the isolator, the polarizer, the output coupler and the second polarization controller, which are sequentially connected into an optical fiber ring cavity through a single-mode optical fiber. At the same time, the adjusting method of the erbium doped fiber laser is also disclosed. The inventioncan realize the pulse output with the center wavelength greater than 1610 nm.

The invention discloses a cascaded stimulated brillouin scattering effect-based wavelength frequency stabilization system, which comprises a tunable single frequency laser (1), a phase modulator (2),a signal generator (3), an optical circulator (4), a multi-wavelength brillouin erbium-doped fiber laser (5), a tunable optical filter (6), a photoelectric detector (7), a microwave mixer (8) and a frequency tracking system (9). A cascaded stimulated brillouin scattering effect is applied to a wavelength frequency stabilization system, and multi-wavelength brillouin laser light generated through the cascaded stimulated brillouin scattering effect is taken as probe light for frequency stabilization, so that high-precision wavelength stabilization is achieved through cooperation with the tunablefilter and the stabilization precision can be improved by 20-50 times. The cascaded stimulated brillouin scattering effect-based wavelength frequency stabilization system is reasonable in design, andhigh-precision optical wavelength stabilization is achieved by adopting the cascaded stimulated brillouin scattering effect.

The invention discloses a THz high-repetition frequency and high-power femtosecond fiber laser based on dispersive waves. The laser comprises an Erbium-doped fiber laser seed source, a frequency enhancement part, an amplification part and a pulse width compression part, wherein the output end of the Erbium-doped fiber laser seed source is connected with the frequency enhancement part via a high non-linear fiber, the output end of the frequency enhancement part is connected with the amplification part, the amplification part comprise a pre-amplification part and a two-stage main amplification part, and the output end of the amplification part is connected with the pulse width compression part; a laser signal generated by the Erbium-doped fiber laser seed source is subjected to non-linear frequency conversion of the high non-linear fiber, and the frequency of the laser signal is enhanced to THz high repetition frequency via the frequency enhancement part, the frequency of the laser signal of the THz high repetition frequency is amplified via the pre-amplification part and the two-stage main amplification part of the amplification part, and the laser signal is further processed by thepulse width compression part to output a high-power femtosecond pulse signal of the THz high repetition frequency. The laser provided by the invention is simple in installation structure, prone to implement, low in cost and convenient to popularize.

The invention provides a multi-wavelength erbium-doped fiber laser with multiple tuning functions. Through the fiber laser, multiple tuning functions can be performed on wavelength intervals, laser spectral line wavelengths, laser spectral line numbers and laser spectral line spectrum ranges. The laser comprises a comb filter, a circulator, a pumping source, a wavelength division multiplexer, an erbium-doped fiber, a polarization controller and a nonlinear loop mirror. By adjusting the polarization state of input light of the comb filter, three comb spectra with three different wavelength intervals can be output. If the polarization state of the input light is further changed, the laser spectral line wavelengths can be tuned. The laser spectral line numbers and the laser spectral line spectrum ranges can be tuned by adjusting the working state of the nonlinear fiber loop mirror. Besides, the laser spectral line numbers can be fine controlled by adjusting the magnitude of the pumping power. The multi-wavelength erbium-doped fiber laser has the advantages of being low in cost, convenient to tune, good in repeatability, good in stability at room temperature and the like.

The invention discloses a C+L band erbium-doped fiber laser based on femtosecond laser direct writing FBGs. The C+L band erbium-doped fiber comprises a sensing fiber, wherein a wavelength division multiplexer is arranged on the sensing fiber and is successively connected in series with a C-band erbium-doped fiber, an L-band erbium-doped fiber, a polarization controller, an FBG array, and a broadband reflector. The FBG array comprises three cascaded FBGs and is produced by a femtosecond laser direct writing method. The three FBGs have the same length and different reflection wavelengths. In theC+L band erbium-doped fiber laser, a femtosecond laser passes through a fiber protective layer to directly write FBGs having periods of 538 nm, 542 nm and 547 nm respectively and connected end to endin a single-mode fiber with a coating unremoved as a frequency selection device, and constitutes a linear cavity fiber laser in combination with the C-band and L-band erbium-doped fibers, a pumping source, the polarization controller and the broadband total reflector, realizes wavelength-switchable single-wavelength and dual-wavelength laser output, and suppresses side modes in the laser spectrum, and improves wavelength stability.

The invention provides a circumduction bistable erbium-doped fiber laser adjustable in bistable region which belongs to optoelectronic device field. The laser includes: first pumped source, first WDM coupler, 10/90 fiber coupler, gain section erbium-doped fiber, second pumped source, third WDM coupler, absorption section erbium-doped fiber. First pumped source connects with first WDM coupler, first WDM coupler connects with gain section erbium-doped fiber, gain section erbium-doped fiber connects with second WDM coupler, second WDM coupler educes unfinished pumped light from circumduction cavity, second WDM coupler connects with third WDM coupler, second pumped source connects with absorption section erbium-doped fiber via third WDM coupler, absorption section erbium-doped fiber connects with 10/90 fiber coupler, 10/90 fiber coupler connect with first WDM coupler. Absorption section erbium-doped fiber leads to optical bistable phenomenon and can adjust optical bistable region size.

The invention discloses an erbium-doped fiber laser based on a 3*3 micro optical fiber coupler and a manufacturing method of the erbium-doped fiber laser. Two end mouths of the three end mouths of one end of the 3*3 micro optical fiber coupler are connected to form a ring in a melting mode, and two end mouths of the three end mouths of the other end of the 3*3 micro optical fiber coupler are connected with the two end mouths of an erbium-doped fiber respectively to form rings in a melting mode. The other end mouths of the two ends of the micro optical fiber coupler are used as a pumping light input end mouth and a laser output end mouth respectively. When 980nm pumping light is input, the laser can stably output a laser of a 1530nm wave band with a contrast ratio exceeding 40dB, a peak width at half height of 0.3nm. Due to the fact that the diameter of a coupled zone is only at a micron level, the coupled zone is provided with a large evanescent field and has excellent good temperature and mechanical performance. Therefore, the laser has large advantages on in a tunable laser and the active sensing of temperature, pressure and a refractive index.

The invention discloses a system for generating medium-wave infrared laser output with a wavelength of not less than 3.8 microns by using a laser differential frequency technology, which utilizes a Yb-doped fiber laser with a wavelength of between 1093 and 1000 nm as pump source, an erbium-doped fiber laser with a wavelength of 1535 to 1540 nm as a signal source, and a nonlinear laser crystal as adevice for optical frequency conversion. After optical fiber beam combining or spatial beam combining, a CW or pulsed Yb-doped fiber laser and the corresponding erbium-doped fiber laser are focused by an optical lens to the nonlinear laser crystal to produce a high efficient medium-wave infrared laser output with a wavelength of not less than 3.8 microns. The invention has the characteristics ofdifference frequency laser output wavelength of not less than 3.8 micron, high laser conversion efficiency, compact system structure, reliable performance, good environmental stability, and suitability for high power output, and has wide application value.

The invention belongs to the optical soliton technology field and particularly relates to an optical soliton pulse generator formed by an erbium-doped-fiber laser. The optical soliton pulse generator formed by erbium-doped-fiber laser comprises a 1*2 optical coupler (1), a 1*N optical switch (2), an optical fiber group (3), a 1*N optical coupler (4), a saturable absorber (5), an optical isolator (6), an erbium-doped fiber (7), an optical wavelength division multiplexer (8), a pump light source (9) and a polarization controller (10). According to the optical soliton pulse generator formed by the erbium-doped-fiber laser, soliton in multiple types such as a ground state optical soliton pulse and a dissipation soliton pulse and bound state multi-soliton of the ground state optical soliton pulse and the dissipation soliton pulse can be obtained in the same passive mode-locking erbium-doped fiber laser system, the performance is stable, and the repeatability is good.

The invention provides an erbium-doped fiber laser of a random Raman fiber laser in-band pumping. The erbium-doped fiber laser sequentially comprises a random laser pumping module, a pumping coupler and an erbium-doped fiber laser. According to the invention, a random fiber laser is used as a pumping source of the erbium-doped fiber laser; pumping light is coupled into the erbium-doped fiber laserthrough the pumping coupler, so that high-power laser output of the laser is realized; the advantages of high efficiency, stability and the like of a traditional erbium-doped fiber laser are maintained; the structure of the in-band pumping erbium-doped fiber laser of the traditional Raman fiber laser is simplified; the problem of erbium-doped fiber thermal management is effectively solved; and the in-band pumping erbium-doped fiber laser has a great development prospect and a high practical value.

The invention discloses a chaotic encryption method for the safety of an FSO (Free Space Optics), and solves the problems that an existing FSO system is easily intercepted in a communication process. The chaotic encryption method comprises the following steps: firstly, performing encryption conversion on a transmitted signal Si and a chaotic signal generated by a monocycle erbium-doped fiber laser system, transmitting the signals to an atmosphere transmission channel, and then receiving the signal in the atmosphere transmission channel by a receiving system, wherein the signal and a synchronous chaotic signal generated by the monocycle erbium-doped fiber laser system can be used for decryption conversion, and the signal obtained by the decryption conversion can be marked as So. According to the chaotic encryption method provided by the invention, the chaotic signal generated by the monocycle erbium-doped fiber laser system can be encrypted to realize the safety transmission of the FSO.

The invention discloses a multi-wavelength Brillouin-erbium-doped fiber laser based on random distribution feedback, and belongs to the technical field of fiber lasers. The multi-wavelength Brillouin-erbium-doped fiber laser based on the random distribution feedback is composed of a Brillouin pumping laser source, an erbium-doped fiber amplifier, an isolator, a first circulator, an erbium-doped fiber pumping laser source, a wavelength division multiplexer, erbium-doped fibers, a second circulator, single mode fibers and random distribution feedback fibers. According to the multi-wavelength Brillouin-erbium-doped fiber laser based on the random distribution feedback, the first circulator, the wavelength division multiplexer, the erbium-doped fibers, the second circulator and the single mode fibers form an annular structure which form a semi-open resonant cavity together with the random distribution feedback fibers, Brillouin pumping laser and feedback optical signals are amplified through the erbium-doped fiber amplifier, therefore amplification of the feedback optical signals can be achieved to the maximum extent, laser oscillation is formed, and multi-wavelength random laser output is finally achieved.