185 results about "Raman pump" patented technology

Optoelectrical conversion of the received optical service signal (OSS), bandpass filtering and subsequent squaring produce a spectral line at the clock frequency (fT). This clock line (TL) is selected by means of narrowband filtering and rectified. The service signal voltage (VTLM) obtained in this manner is used to switch on a Raman pump laser (11).

An optical transmission system that employs a Raman amplifier including a Raman pump for introducing depolarized pump light into the fiber. The pump includes an optical source generating a polarized optical pump signal, an optical splitter that splits the pump signal into a first pump portion and a second pump portion, and a beam combiner that combines the first pump portion and the second pump portion into the depolarized pump light. Further, the pump includes a delay device, such as a length of fiber, that causes the first pump portion to propagate farther from the beam splitter to the beam combiner than the second pump portion. The length of fiber is longer than the coherence length of the pump signal.

The invention discloses a distributed optical fiber Brillouin sensor fused with an optical fiber Brillouin frequency shifter, which is a distributed optical fiber sensor manufactured through the frequency shift effect of Brillouin scattering of an optical fiber, an optical fiber broadband nonlinear optical amplification effect, the strain and temperature effects of Brillouin scattered light of coherent amplification, and an optical time domain analysis principle, and comprises a narrow linewidth single frequency optical fiber laser, three optical fiber branching devices, a pulse modulator, the optical fiber Brillouin frequency shifter, two optical fiber circulators, an erbium-doped optical fiber amplifier, a polarization mode scrambler, an optical fiber narrowband reflection filter, an optical fiber Raman pump laser, a single-mode sensing optical fiber, an optical fiber filter, a photoelectric reception amplifier module, two digital signal processors, a photoelectric heterodyne reception amplifier module and a computer, wherein the optical fiber Brillouin frequency shifter is formed by connecting the circulators, the single-mode optical fiber and the optical fiber Fabry-Perot (F-P) filter in turn. The sensor has a simple structure, low price and high measuring accuracy and stability.

The invention is in the field of distributed Raman amplification for digital and analog transmission applications and other applications, e.g., instrumentation and imaging applications, including HFC-CATV applications. In particular, the invention uses a high power broadband source of amplified spontaneous emission (ASE) as the Raman pump source for improved system performance. The invention also includes methods for constructing such a high-power broadband Raman pump.

The invention is in the field of distributed Raman amplification for digital and analog transmission applications and other applications, e.g., instrumentation and imaging applications, including HFC-CATV applications. In particular, the invention uses a high power broadband source of amplified spontaneous emission (ASE) as the Raman pump source for improved system performance. The invention also includes methods for constructing such a high-power broadband Raman pump.

An apparatus and method for measuring Raman-type spectra using optical dispersion to convert an optical spectrum into a waveform which can be detected directly in the time domain without the use of a conventional spectrometer. In the example of stimulated Raman spectroscopy, the apparatus and method exposes a sample to a chirped, pulsed probe beam and a Raman pump beam and the resulting Raman spectra is detected by an optical detector in the time domain, and analyzed. Alternatively, the Raman spectra from the probe and pump beams is chirped with a dispersive element prior to detection and analysis. Each probe pulse provides a snapshot of the Raman spectrum that is sampled in time so that neither repetitive waveforms nor static samples are required. Therefore, high speed acquisitions and high throughput assays can be conducted. To facilitate detection, these spectral signals can also be amplified using distributed Raman amplification directly in the dispersive element.

The invention discloses a long-distance optical fiber vibration sensing system with distributed amplification. The system comprises a Raman pump laser, a seed laser, a modulator connected with the seed laser, a circulator connected with the modulator, an optical fiber amplification filter connected with the circulator, a photoelectric transducer connected with the optical amplification filter, a collector connected with the photoelectric transducer, and a signal processor connected with the collector. The system has the advantages of capacity of monitoring long-distance border lines, high sensitivity and exact positioning accuracy.

An optical probe assembly for conveying Raman pump light to a specimen and for conveying a Raman signature from the specimen to an optical spectrum analyzer, the optical probe assembly comprising a light guide, wherein the light guide comprises a core region and a surrounding cladding region, wherein the core region is constructed so as to minimize the creation of a relatively broadband spurious background noise signal when conveying the Raman pump light to the specimen, and the cladding region is constructed so as to satisfy the wave guiding reflection requirements of the Raman pump light and the Raman signature. A Raman spectroscopy system comprising: a laser for producing Raman pump light; an optical probe assembly for conveying the Raman pump light to a specimen and for conveying a Raman signature from the specimen to an optical spectrum analyzer, the optical probe assembly comprising a light guide, wherein the light guide comprises a core region and a surrounding cladding region, wherein the core region is constructed so as to minimize the creation of a relatively broadband spurious background noise signal when conveying the Raman pump light to the specimen, and the cladding region is constructed so as to satisfy wave guiding reflection requirements of the Raman pump light and the Raman signature; and an optical spectrum analyzer for receiving the Raman signature of a specimen and identifying and characterizing the specimen based upon the spectrum of the Raman signature. A method for conducting Raman spectroscopy comprising: producing Raman pump light; conveying the Raman pump light through an optical probe assembly to a specimen and conveying a Raman signature from the specimen through the optical probe assembly to an optical spectrum analyzer, the optical probe assembly comprising a light guide, wherein the light guide comprises a core region and a surrounding cladding region, wherein the core region is constructed so as to minimize the creation of a relatively broadband spurious background noise signal when conveying the Raman pump light to the specimen, and the cladding region is constructed so as to satisfy wave guiding reflection requirements of the Raman pump light and the Raman signature; and identifying and characterizing the specimen based upon the spectrum of the Raman signature.

A system and method for providing eye-safety protection during operation of distributed Raman amplifiers based on the application of continuous out-of-band amplified spontaneous scattering (ASS) monitoring in an optical communication network span coupled to the Raman amplifier, and real-time detection and analysis of changes in the monitored ASS power level, The system includes at least one Raman pump for introducing Raman energy into the span, a monitoring unit for performing the continuous ASS monitoring, and a control unit operative to detect and analyze in real-time changes in the ASS power, and upon determination that such changes indicate an open span, to reduce the level of the Raman pump energy entering the span to a safe level.