Patent application number | Description | Published |
20090185263 | OPTICAL FIBER FOR AMPLIFICATION - Provided is an erbium doped optical fiber (EDF) for amplification which allows an easy estimation of the amplification performance and high production stability. The fiber includes a core and a cladding. The core is mainly made of silica glass and doped with erbium at a concentration of 500 wtppm or more and 2500 wtppm or less. In the fiber, the cutoff wavelength is 850 nm or more and 1450 nm or less, the mode field diameter is 4.5 μm or more and 6.5 μm or less, the polarization mode dispersion is not more than 0.1 ps per 10 m, the coordination number of oxygen elements around an erbium element in the core is one or more and eight or less, and the bond length between erbium and oxygen is 0.225 nm or more and 0.235 or less. | 07-23-2009 |
20100284658 | Optical fiber, optical transmission line, optical module, and optical transmission system - The present invention relates to an optical fiber which has a structure for further increasing an FOM (=|dispersion|/loss) and which can be applied to a dispersion compensation module. The optical fiber is mainly composed of silica glass and has a core region including a center of an optical axis, a depressed region surrounding the core region, a ring region surrounding the depressed region, and a cladding region surrounding the ring region and doped with F. As compared with the refractive index of pure silica glass, a relative refractive index difference of the core region is greater than 2% but less than 3%, a relative refractive index difference of the depressed region is −1% or more but −0.5% or less, a relative refractive index difference of the ring region is 0.01% or more but 0.24% or less, and a relative refractive index difference of the cladding region is −0.3% or more but −0.1% or less. The FOM at the wavelength of 1550 nm is 250 ps/nm/dB or more. | 11-11-2010 |
20110085768 | OPTICAL FIBER AND METHOD OF MANUFACTURING OPTICAL FIBER - An optical fiber having excellent strength that can be manufactured at low cost, as well as a method for making such optical fiber, is provided. An optical fiber | 04-14-2011 |
20120014654 | OPTICAL FIBER AND METHOD FOR MANUFACTURING SAME - Provided is an optical fiber having a large relative refractive index difference and a reduced transmission loss, as well as a manufacturing method therefor. An optical fiber preform | 01-19-2012 |
20120189262 | OPTICAL FIBER PREFORM, OPTICAL FIBER, AND METHOD OF MANUFACTURING OPTICAL FIBER PREFORM - An optical fiber preform includes a core portion, in which the core portion includes an alkali-metal-doped core glass portion doped with an alkali metal, the maximum concentration of oxygen molecules in the core portion is 30 mol ppb or more, and the average concentration of the alkali metal in the core portion is 5 atomic ppm or more. A method of manufacturing an optical fiber preform includes an alkali-metal-doping step of doping a pipe composed of silica-based glass with an alkali metal, an oxygen-molecule-doping step of doping the glass pipe with oxygen molecules, and a collapsing step of collapsing the glass pipe by heating the glass pipe, in which the optical fiber preform is manufactured. | 07-26-2012 |
20120192593 | METHOD FOR PRODUCING OPTICAL FIBER PREFORM - There is provided a method for producing an optical fiber preform used in producing an optical fiber having low attenuation. The production method includes (1) a rod formation step of forming a glass rod of a silica glass containing an alkali metal element, the average concentration of the alkali metal element being 5 at·ppm or more, (2) a heat treatment step of heat-treating the glass rod, (3) a core part formation step of forming an alkali metal element-free silica glass layer having a chlorine concentration of 6000 at·ppm or more around the perimeter of the glass rod heat-treated in the heat treatment step to form a core part including the glass rod and the silica glass layer, and (4) a cladding part formation step of forming a cladding part of a silica-based glass having a lower refractive index than the core part around the perimeter of the core part. | 08-02-2012 |
20120198891 | METHOD FOR PRODUCING OPTICAL FIBER PREFORM - A method for producing an optical fiber preform according to the present invention includes a collapse step of collapsing a silica-based glass tube by heating with a heat source continuously traversed in the longitudinal direction of the glass tube to form a first glass rod to be formed into a core part or part of a core part of an optical fiber, the glass tube having an inner surface doped with an alkali metal, in which the glass tube has a maximum alkali metal concentration of 500 to 20,000 atomic ppm, a maximum chlorine concentration of 0 to 1000 atomic ppm, and a maximum fluorine concentration of 0 to 10,000 atomic ppm, and in which in the collapse step, the maximum temperature of the outer surface of the glass tube is 2000° C. to 2250° C., and the traverse speed of the heat source is 30 mm/min to 100 mm/min. | 08-09-2012 |
20120198892 | METHOD FOR PRODUCING OPTICAL FIBER PREFORM - A method for producing an optical fiber preform according to the present invention includes an etching step of heating a silica-based glass tube using a heat source continuously traversed in the longitudinal direction of the glass tube to etch the inner surface portion of the glass tube containing impurities while an etching gas is allowed to flow into the glass tube. The glass tube has a maximum alkali metal concentration of 500 to 20,000 atomic ppm, a maximum chlorine concentration of 0 to 1000 atomic ppm, and a maximum fluorine concentration of 0 to 10,000 atomic ppm. In the etching step, the maximum temperature of the outer surface of the glass tube is in the range of 1900° C. to 2250° C., and the heating time is set to a time equal to or less than a time (min) given by | 08-09-2012 |
20120263427 | OPTICAL FIBER AND OPTICAL FIBER PREFORM - An optical fiber preform has a core portion having a first core portion including a central axis, a second core portion disposed around the first core portion, and a third core portion disposed around the second core portion. The first core portion contains 10 atomic ppm or more of an alkali metal and 10 to 600 atomic ppm of chlorine, the second core portion contains 10 atomic ppm or less of the alkali metal and 10 to 600 atomic ppm of chlorine, and the third core portion contains 10 atomic ppm or less of the alkali metal and 2,000 atomic ppm or more of chlorine. An optical fiber has a core region doped with an alkali metal and chlorine, wherein the minimum concentration of chlorine in the core region is 1,000 atomic ppm or more, and the average concentration of the alkali metal therein is 0.2 atomic ppm or more. | 10-18-2012 |
20120321261 | METHOD FOR PRODUCING OPTICAL FIBER - There is provided a method for producing an optical fiber having low attenuation, the optical fiber including a core that contains an alkali metal element. An optical fiber preform that includes a core part and a cladding part is drawn with a drawing apparatus to form an optical fiber, the core part having an average concentration of an alkali metal element of 5 atomic ppm or more. During the drawing, the time the temperature of glass is maintained at 1500° C. or higher is 110 minutes or less. The drawing speed is preferably 1200 m/min or more and more preferably 1500 m/min to 2300 m/min. The optical fiber preform preferably has a diameter of 70 mm to 170 mm and more preferably 90 mm to 150 mm. | 12-20-2012 |
20130034654 | METHOD FOR MAKING AN OPTICAL FIBER PREFORM - A method for the manufacture of an optical fiber preform for producing a low attenuation optical fiber with high yield, comprising preparing a core rod and adding a cladding region. At the step of preparing a core rod, the core rod is produced including a first core region with Cl density of less than 600 atm-ppm, a second core region with Cl density of less than 600 atm-ppm around the first core region, and a third core region with Cl density of 3000 atm-ppm or more around the second core region. An alkali metal is selectively added to the first core region among the first, second, and third core regions. A cladding region is formed around the core rod by heating at a temperature of 1200° C. or higher for 7 hours or less. | 02-07-2013 |
20130077925 | OPTICAL FIBER - An optical fiber includes a core section and a cladding section. A k value expressed by k=4Aeff/(πMFD | 03-28-2013 |
20130188917 | OPTICAL FIBER AND OPTICAL FIBER PREFORM - An optical fiber containing an alkali metal element and exhibiting low attenuation as well as excellent radiation resistance is provided. The optical fiber of the present invention has a core region and a cladding region enclosing the core region. The core region contains alkali metal elements by an average concentration of 0.2 atomic ppm or more. The attenuation at a wavelength of 1550 nm after irradiating with the radiation of 0.10 Gy or more of cumulative absorbed dose increases by 0.02 dB/km or less as compared with the attenuation exhibited prior to radiation exposure. | 07-25-2013 |
20140127507 | METHOD FOR MANUFACTURING OPTICAL FIBER BASE MATERIAL, AND OPTICAL FIBER - A method for making a high quality optical fiber preform includes: thermally defusing the alkali metal element into the inner side of a silica glass pipe by heating the glass pipe from the outside by a heat source while vapors of alkali metal salt generated by heating an alkali metal salt is supplied to the inside of the glass pipe from an end thereof; collapsing the glass pipe for forming a core rod; and adding a cladding part around the circumference of the core rod. At the start of the thermal diffusion, the alkali metal salt is heated at a temperature for making the vapor pressure of the alkali metal salt to be 0.1 kPa or less, and thereafter the alkali metal salt is heated up to a temperature for making the vapor pressure of the alkali metal salt to be larger than 0.1 kPa. | 05-08-2014 |
20140137604 | OPTICAL FIBER AND METHOD OF MANUFACTURING OPTICAL FIBER - An optical fiber having excellent strength that can be manufactured at low cost, as well as a method for making such optical fiber, is provided. An optical fiber | 05-22-2014 |
20140254997 | OPTICAL FIBER PREFORM, METHOD FOR PRODUCING OPTICAL FIBER, AND OPTICAL FIBER - An easily producible optical fiber preform which is drawn to an optical fiber having a core containing a sufficient concentration of alkali metal is provided. An optical fiber preform | 09-11-2014 |
20140370287 | METHOD FOR PRODUCING OPTICAL FIBER PREFORM, OPTICAL FIBER PREFORM, AND OPTICAL FIBER - An optical fiber preform producing method is a method for producing an optical fiber preform including a core part and a cladding part and being composed of silica-based glass, which has: an alkali metal adding step of adding an alkali metal in a maximum concentration of not less than 500 ppm in the vicinity of an inner surface of a glass pipe composed of silica glass; an etching step of etching the inner surface of the glass pipe by vapor phase etching under flow of SF | 12-18-2014 |
20150027170 | METHOD FOR PRODUCING OPTICAL FIBER - Provided is a method for producing an optical fiber having low attenuation and including a core that contains an alkali metal element. An optical fiber preform that includes a core part and a cladding part is drawn with a drawing apparatus | 01-29-2015 |
Patent application number | Description | Published |
20080212091 | Light source unit and spectrum analyzer - A light source unit and a spectrum analyzer are provided in which the influence of interference can be reduced under conditions where light is separated into spectral components. A spectrum analyzer | 09-04-2008 |
20090078870 | Infrared imaging system - The present invention relates to a long-life, low-power consumption infrared imaging system having a structure for realizing with a high reliability both the taking of an image of its surrounding environments and the detection of objects. The infrared imaging system comprises a light source section, an image pickup section, a processing section, and a monitor. For emitting SC light including a wavelength component in a near-infrared wavelength band as irradiation light, the light source section includes a seed light source emitting laser light, an optical fiber generating the SC light in response to the input of the laser light, and wavelength selecting means. The wavelength selecting means selectively limits the wavelength region of the irradiation light in accordance with imaging modes. In the mode for taking an image of a surrounding environment, the wavelength selecting means limits the irradiation light wavelength to a wavelength band excluding an absorption wavelength band of moisture and the like in the air. In the mode for detecting an object such as a frozen part on the road surface, on the other hand, the wavelength selecting means limits the irradiation light wavelength to an absorption wavelength band of water or ice. | 03-26-2009 |
20090103171 | OPTICAL FIBER FOR AMPLIFICATION AND OPTICAL FIBER AMPLIFIER - Provided is an optical fiber for amplification and an optical fiber amplifier for use in L-band, in which optical fiber the increase of transmission loss and the degradation of hydrogen-resistant characteristic can be restrained. The optical fiber is basically made of silica glass and comprises: a core region doped with erbium and P element of 2 wt % to 5 wt % concentration, Ge not being added thereto; and a cladding region enclosing the core region and doped with F element, wherein the optical fiber has a gain at least in a wavelength range of 1570 to 1620 nm. The optical fiber amplifier comprises: the optical fiber; a pump light source for outputting the pump light capable of exciting a rare-earth element added to the core region of the optical fiber; and an optical coupler for introducing into the optical fiber the pump light having been output from the pump light source. | 04-23-2009 |
20100071420 | Optical Fiber Preform Fabricating Method, Optical Fiber Fabricating Method and Optical Fiber - The present invention relates to an optical fiber preform fabricating method that makes it possible to implement a reduction in iron impurities at a low cost. The optical fiber preform fabricating method comprises a glass synthesis step for forming a glass region constituting at least a part of the core area of the optical fiber. The glass synthesis step includes a deposition step of depositing glass particles containing the Al-element inside the glass pipe by means of chemical vapor deposition, and a consolidation step of obtaining a transparent glass body from the glass soot body thus obtained. In other words, the deposition step synthesizes glass particles on the inside wall of a glass pipe by feeding raw material gas, in which the content ratio (O/Al) of the O-element and Al-element is 20 or less, into the glass pipe. Furthermore, the consolidation step obtains a transparent glass body from the glass soot body by heating the glass soot body. The transparent glass body that is formed in the consolidation step constitutes part of the core region. | 03-25-2010 |