278 results about "Stimulate raman scattering" patented technology

A method and apparatus that reduces laser speckle by using stimulated Raman scattering in an optical fiber. The pulse repetition frequency of the laser is adjusted to control aspects of the laser light such as color or despeckling. In DLP projection systems, an optical monitor may be used to send information to a bit sequence, and the bit sequence may control the pulse repetition frequency of the laser based on the optical monitor signal.

The invention discloses super-far distributed fiber Raman and Brillouin photon sensors; by using the stimulated Raman scattering effect of fiber, the self Raman scattering effect of fiber, the Brillouin scattering effect of fiber and the light time-field reflection principle, distributed fiber Raman photon temperature sensors, distributed fiber Brillouin photon strain sensors and distributed fiber Raman amplifier are integrated together. Fiber consumption is overcome by using the gain of amplifier, and strengths of self Raman scattering light and Brillouin scattering light in fiber is enhanced, the signal to noise ratio of the system of distributed fiber Raman photon sensor and distributed fiber Brillouin photon strain sensor is enhanced, meanwhile, the transmission distances of distributed fiber Raman photon sensor and distributed fiber Brillouin photon strain sensor are increased, finally, the temperature and stress measuring accuracy is enhanced.

A pulsed cascaded Raman laser (10) includes a pulsed light source (102) for generating a pulsed light (104) having an optical spectrum centered at a source wavelength. A non-linear Raman conversion fiber (106) is coupled to the pulsed light source (102). The pulsed light (104) traverses the nonlinear Raman conversion fiber (106) and the source power at the source wavelength is converted to a power output of an output signal (108) having an output wavelength longer than the source wavelength by a cascaded Stimulated Raman Scattering process, such that most of the source power is converted to the power of the last Stokes order in a single pass through the non-linear Raman conversion fiber (106).

Systems and methods employing Coherent Raman Scattering (CRS), e.g., Coherent anti-Stokes Raman Spectroscopy (CARS) and / or Stimulated Raman Scattering (SRS) are provided. Systems and methods for performing flow cytometry, imaging and sensing using low-resolution CRS are also provided.

A hybrid fiber cable network includes multiple nodes, each of which receives a first multi-carrier return signal from multiple customers with carrier signals in a first frequency band. In a fiber-hub, one or more first multi-carrier signals are converted into a second multi-carrier signal with carrier signals in a second band. Each information signal modulates a different higher frequency carrier signal in the second signal. A multitude of second multi-carrier signals are converted into optical signals with different optical wavelengths, multiplexed onto an optical fiber, and transmitted to the head-end. The first frequency band is below 200 MHz, preferably from 5 to 50 MHz. The second frequency band is above 200 MHz, preferably between 300 and 1200 MHz to reduce crosstalk due to stimulated Raman scattering (SRS). Preferably, each second frequency band is no more than one octave wide, and more preferably, no more than one half an octave wide.

A solid state Raman laser includes a laser pump for producing a first radiation at a high power and at a first wavelength along an optical path, a solid Raman active medium in the optical path of the first radiation, the medium including single crystal diamond having a first surface and a second surface, where the first radiation at a high power produces stimulated Raman scattering in the medium and the medium generates a second radiation at a second wavelength, a first optical element in the optical path of the first radiation, wherein the first optical element allows the first wavelength to be transmitted and allows the second wavelength to be reflected, and a second optical element in the optical path of the first radiation, wherein the second optical element allows the first wavelength to be transmitted and allows the second wavelength to be reflected.

A small, low power consumption light amplifier using stimulated Raman scattering is provided. A Raman active section 18 and a rough surface metal part 21 are provided on one end face of an optical fiber 11, excitation light is irradiated onto the rough surface metal part 21, surface plasmon is generated and signal light 15 is amplified into amplified signal light 16 using stimulated Raman scattering in the interface between the rough surface metal part 21 irradiated with the signal light 15 which has propagated through the core 12 and the Raman active section 18.

Decreasing the average transmitted power in an optical fiber communication channel using multilevel amplitude modulation in conjunction with Pulse Position Modulation (PPM). This multilevel PPM method does not entail any tradeoff between decreased power per channel and channel bandwidth, enabling a lower average transmitted power compared to On / Off Keying (OOK) with no reduction in aggregate data rate. Therefore, multilevel PPM can be used in high-speed Dense Wavelength Division Multiplexed (DWDM) systems where the maximum number of channels is traditionally limited by nonlinear effects such as self-phase modulation (SPM), cross-phase modulation (XPM), four-wave mixing (FWM), stimulated Brillouin scattering (SBS), and stimulated Raman scattering (SRS). This modulation technique can enable an increased number of channels in DWDM systems, thereby increasing aggregate data rates within those systems.

A method and apparatus for despeckling that includes a green laser diode, a DPSS laser, and stimulated Raman scattering light formed in an optical fiber. The laser diode light and stimulated Raman scattering light are combined to form a projected digital image. The output of the optical fiber may be split into two spectrums. The projected digital image may be stereoscopic with one image formed from the laser diode light and one spectrum, and the other image formed from the other spectrum.

A method and apparatus for generating and transmitting high energy optical pulses are described. Distributed temperature sensors usually use Raman scattering in optical fibres as the means to determine the temperature. Here, light from a laser source is sent down a fibre and the small amount of light that is scattered back towards the source is analysed. As the fibre length increases, the resolutions of the temperature and loss measurements become poorer. This is because losses in an optical fibre attenuate the signal. An obvious solution to this problem is to launch more light into the fibre to compensate for the losses but stimulated Raman scattering limits how much light may be launched. The present invention solves this problem by using a pulse conversion method to maximise the resultant pulse energy while the power is kept below SRS threshold.

An optical transmission system and method may control optical signal transmission in an optical network, such as a passive optical network (PON), to reduce degradation of one or more optical signals traveling over the same optical waveguide. In particular, optical signal transmission may be controlled to reduce carrier to noise ratio (CNR) degradation of an optical signal (e.g., a multichannel video signal) resulting from the effects of stimulated Raman scattering (SRS) and / or double Rayleigh backscattering (DRBS). The CNR degradation may be reduced by controlling transmission of one or more of a plurality of optical signals in the optical network based on various parameters affecting the contribution to CNR degradation by SRS and / or DRBS and affecting the performance of the optical transmission system. The optical signal transmission may be controlled by adjusting a preemphasis and / or transmitted power of the optical signal(s).

Briefly, the present invention relates to a system for combining the output light beams of a plurality of semiconductor laser diodes, for example, to form a combined light beam with increased brightness. The output light beams from the semiconductor laser diodes are coupled to a plurality of optical fibers forming a fiber coupled diode array. The optical fibers forming the fiber coupled diode array are coupled to a dual clad optical fiber with a central core. The output light beams from the optical fibers from the fiber coupled diode array are coupled to the inner cladding of a dual clad optical fiber. A Stokes seed source is applied to the central core, and the inner-clad diode light acts as a pump source to amplify the Stokes beam by stimulated Ramans scattering, thereby transferring power from the inner cladding into Stokes beam in the central core. The configuration in accordance with the present invention provides a Stokes output light beam with a relatively higher brightness level than known techniques which merely combine the output light beams from a plurality of semiconductor diodes and eliminates the need for a relatively precise alignment and the cost associated with the lenses required by known systems.

An optical source capable of enhanced scaling of pulse energy and brightness utilizes an ensemble of single-aperture fiber lasers as pump sources, with each such fiber laser operating at acceptable pulse energy levels. Beam combining involves stimulated Raman scattering using a Stokes' shifted seed beam, the latter of which is optimized in terms of its temporal and spectral properties. Beams from fiber lasers can thus be combined to attain pulses with peak energies in excess of the fiber laser self-focusing limit of 4 MW while retaining the advantages of a fiber laser system of high average power with good beam quality.

Briefly, the present invention relates to a system for combining the output light beams of a plurality of semiconductor laser diodes, for example, to form a combined light beam with increased brightness. The output light beams from the semiconductor laser diodes are coupled to a plurality of optical fibers forming a fiber coupled diode array. The optical fibers forming the fiber coupled diode array are coupled to a dual clad optical fiber with a central core. The output light beams from the optical fibers from the fiber coupled diode array are coupled to the inner cladding of a dual clad optical fiber. A Stokes seed source is applied to the central core, and the inner-clad diode light acts as a pump source to amplify the Stokes beam by stimulated Ramans scattering, thereby transferring power from the inner cladding into Stokes beam in the central core. The configuration in accordance with the present invention provides a Stokes output light beam with a relatively higher brightness level than known techniques which merely combine the output light beams from a plurality of semiconductor diodes and eliminates the need for a relatively precise alignment and the cost associated with the lenses required by known systems.

The invention relates to a random-distribution feedback optical fiber laser which can realize stable, space-irrelevant and continuous laser output, and belongs to the technical field of the optical fiber laser. The random-distribution feedback optical fiber laser comprises a pump laser, a wavelength division multiplexer, a fiber bragg grating, an Er-doped optical fiber, an optical fiber Raman laser and a long monomode optical fiber. The reflection effect of the fiber bragg grating is combined with the distributed Rayleigh scattering effect of the optical fiber to form a distributed random feedback optical resonant cavity; and the light is subjected to gain amplification by an Er-doped optical fiber and the stimulated Raman scattering effect. Compared with the random-distribution feedback optical fiber laser reported before, the threshold value of the pump laser and the length of the monomode optical fiber can be reduced, and the limitation on stimulated emission wavelength and the wavelength number by a Rayleigh gain peak is broken through, thereby realizing the purpose of tuning the laser wavelength. The random-distribution feedback optical fiber laser is suitable for fields, such as remote optical fiber sensing, remote communication and the like.

Two-pump optical parametric devices (OPDs), and methods of operating the same, generate desired output signals and idlers having reduced stimulated Raman scattering (SRS) noise levels. When the two-pump OPD is used as a two-pump optical parametric amplifier (OPA), the pumps are polarized perpendicular to each other, and the lower-frequency sideband (signal or idler) is polarized parallel to the lower-frequency pump (perpendicular to the higher-frequency pump). The desired output may be an amplified signal or a generated idler. When the two-pump OPD is used as a two-pump optical frequency converter (OFC), the pumps can be polarized parallel to one another, in which case the signal and idler are both perpendicular to the pumps, or perpendicular to one another, in which case the lower-frequency sideband (signal or idler) is polarized parallel to the lower-frequency pump (perpendicular to the higher-frequency pump).

The invention relates to a graphite Raman locked mode laser characterized in that laser gain is provided by a stimulated Raman scattering effect with a flexible wavelength and combined with a graphite Raman locked mode device with a wide saturated absorption band to realize locked mode laser output. The whole device of the graphite Raman locked mode laser is formed by a mechanism of combining a stimulated Raman gain medium with the graphite Raman locked mode device, is compact in structure and convenient to integrate and can be applied to a plurality of fields.

The present invention discloses an ultra-long-range distributed fiber Raman photon temperature sensor of an integrated Raman amplifier, and comprises a distributed fiber Raman photon temperature sensor, a distributed fiber Raman amplifier and a fiber grating narrowband reflecting filter. The distributed fiber Raman amplifier is adopted to be embedded into the distributed fiber Raman photon temperature sensor; the gain of the amplifier is used to overcome fiber loss, strengthen the intensity of spontaneous Raman scattering light in the fiber, improve signal-to-noise ratio of the distributed fiber Raman photon temperature sensor system, augment the transmission distance of the distributed fiber Raman photon temperature sensor and improve temperature-measuring precision. With the fiber stimulated Raman scattering effect, the fiber spontaneous Raman scattering effect and the optical time domain reflection principle, the invention skillfully merges the technologies of the distributed fiber Raman amplifier and the distributed fiber Raman photon temperature sensor and achieves the ultra-long-range distributed fiber Raman temperature sensor.

An optically amplified wavelength division multiplexing network has the functionality to add / drop channels at the optical add / drop multiplexing (OADM) nodes. The OADM node includes a receiver amplifier, an OADM module, and a transmitter amplifier. Once the OADM node detects a loss of signal (LOS) due to a fiber cut or network element failure upstream, the receiver amplifier is kept in operation as a noise source. The output of the receiver amplifier is immediately raised by increasing pump power to compensate for the LOS. The noise power received at the transmitter amplifier from the receiver amplifier is substantially equal to the signal power expected before LOS. The transient effect of downstream optical amplifiers is therefore completely suppressed and the inter-channel stimulated Raman scattering (SRS) induced spectrum tilt does not change. After the noise power is raised, the receiver amplifier may be shut down at a speed much slower than the speed of downstream amplifier control circuitry.

An apparatus and method that reduces laser speckle by using stimulated Raman scattering in an optical fiber. The fiber core diameter and length are selected to achieve a desired output color. An adjustable despeckler is formed by combining two optical fibers in parallel and adjusting the amount of light in each path.

An optically amplified wavelength division multiplexing network has the functionality to add / drop channels at the optical add / drop multiplexing (OADM) nodes. The OADM node includes a receiver amplifier, an OADM module, and a transmitter amplifier. Once the OADM node detects a loss of signal (LOS) due to a fiber cut or network element failure upstream, the receiver amplifier is kept in operation as a noise source. The output of the receiver amplifier is immediately raised by increasing pump power to compensate for the LOS. The noise power received at the transmitter amplifier from the receiver amplifier is substantially equal to the signal power expected before LOS. The transient effect of downstream optical amplifiers is therefore completely suppressed and the inter-channel stimulated Raman scattering (SRS) induced spectrum tilt does not change. After the noise power is raised, the receiver amplifier may be shut down at a speed much slower than the speed of downstream amplifier control circuitry.

Bending of an optical fiber where a heat may be generated by a high output power can be detected without using a dedicated light source. An optical communication module that outputs a continuous wave light generated by at least one light source to an optical fiber transmission line, includes: (1) a loss measurement unit that measures a loss of an amplified spontaneous emission generated by allowing the continuous wave light output from the light source to create stimulated Raman scattering in the optical fiber transmission line; (2) a fiber abnormality analyzer that detects the abnormal state of the optical fiber transmission line on the basis of loss information on the ASE measured by the loss measurement unit; and (3) a light source controller that controls a supply state of the continuous wave light from the light source on the basis of the detection of the fiber abnormality analyzer.

The present invention relates to a super continuum light source comprising a pump source arranged to emit light having a center wavelength λcenter arranged to provide pump pulse to a generator fibre, where the refractive index profile of the core is arranged to allow modal cleaning of the light is it propagates, such as via stimulated Raman scattering. An example of invention is the application of a relatively high power pump laser utilized to provide an optical super continuum with relatively high spectral density and / or good beam quality even though the pump laser may provide a beam with a high M2.

A method of despeckling light that includes mixing high-speckle laser light with low-speckle laser light in amounts selected to achieve a desired color point in a digital image. The high speckle laser light may be red laser diodes and the low-speckle laser light may be green stimulated-Raman-scattering light from an optical fiber. The desired color point may be DCI red or Rec. 709 red.

The invention relates to a full-solid-state single longitudinal mode yellow light laser which is characterized in that pump light emitted from a pump source is collimated and focused through an optical coupling system and is emitted to a self-Raman crystal through an input mirror, and the self-Raman crystal absorbs base frequency light generated by pump light energy in a self-Raman resonant cavity; the base frequency light is spread in the self-Raman resonant cavity in a reciprocating mode, is polarized through a Brewster window to form linear polarized light, lambda / 4 wave plate combination is used for enabling light spread in the self-Raman crystal on the inner side of the lambda / 4 wave plate combination to be circular polarized light and light spread in the self-Raman crystal on the outer side of the lambda / 4 wave plate combination to be linear polarized light, and therefore multimode oscillation caused by space burning holes can be effectively eliminated, and single longitudinal mode base frequency light is output; when the light field strength of the base frequency light gradually increases to reach a Raman threshold, the single longitudinal mode base frequency light is subjected to stimulated Raman scattering of the self-Raman crystal and is converted to single longitudinal mode Stokes light, and the Stokes light passes through a frequency doubling crystal to generate single longitudinal mode yellow light which is output to the outside of the cavity through an output mirror or a beam splitter. The full-solid-state single longitudinal mode yellow light laser can be widely applied to the manufacturing process of full-solid-state single longitudinal mode yellow light lasers.

The invention relates to a different modal molecular vibration spectrum detection and imaging device and a method. The device mainly consists of related apparatuses of functional units such as a laser unit, an optical scanning microscopic unit, a stimulated Raman scattering signal probing and acquiring unit and a spontaneous Raman spectrum detection member and the like. In light of implementation by the method, two different modal molecular vibration scattered signals are quickly acquired in situ on a living cell, an isolated biological tissue and a living small animal: spontaneous Raman spectrum detection under a single laser beam working mode and stimulated Raman scattering microimaging under a double laser beam working mode to achieve quantitative microimaging and qualitative spectral analysis on a target so as to obtain characteristic information of target components, thereby providing important data for optical analysis and deep analysis of a sample.