Abstract:
A method for reducing the hydrogen sensitivity of an optical fiber is disclosed. The method includes a deuterium treatment step of exposing an optical fiber to a gas mixture including a deuterium, so that the optical fiber makes a contact with the deuterium, and a degassing step of degassing the optical fiber treated with the deuterium under a negative pressure condition.
Abstract:
PURPOSE: A recording medium recording data for preventing disk duplication using a BCA(Burst Cutting Area), a modulating method, a recording device, and a reproducing device are provided to remove needs of a separate modulation table and increase recording density in the BCA by generating a channel bit, as the channel bit after modulation is inserted into data bit before the modulation as a start pattern. CONSTITUTION: A controller(820) generates control information modulated by using an OOK(on-Off Keying) modulating method. A recorder(810) records the information generated from the controller to the BCA formed on an optical disk(800). A signal generated by using the OOK modulating method is an RZ(Return-to-Zero) signal. The OOK modulating method converts 2 data bits into 3 channel bits.
Abstract:
PURPOSE: A method and a device for generating an ECC(Error Correction Code) block of an optical disk are provided to form an appropriate ECC block if an amount of data of an ECC block is bigger than an amount of data recorded on the innermost track of the first area where data except user data is recorded, thereby improving error detection efficiency and error correction performance. CONSTITUTION: Size information (B+C)xA of an ECC block of the second area used for a recording medium is inputted. An ECC block (B'+C')xA' for the second area is created by using the inputted size information. The ECC block (B'+C')xA' is in relation to (B'+C')xA'={(B+C)xA}/2, and here, B' is B/2 while C' is C/2, then A' is A. B refers to 216 while C refers to 32, or B is 108 and C is 16.
Abstract:
PURPOSE: A device of compensating for a synchronous signal and a method thereof are provided to generate a synchronous signal having a certain section length based on an information detection signal produced at a normal time, if extracted features are abnormal. CONSTITUTION: An information recording section detector(11) detects an information recording section of a signal, and generates an information detection signal having a high information recording section. A synchronous signal compensator/generator(12) extracts features of the high section of the information detection signal, generates a window signal based on the information detection signal produced when the extracted features are normal, and generates a synchronous signal based on the information detection signal produced at a normal time when a phase difference between the information detection signal and the window signal is within an error range and the extracted features are normal. If the phase difference is within the error range and the extracted features are abnormal, the compensator/generator(12) generates a synchronous signal having a certain high section length.
Abstract:
An apparatus and method for manufacturing an optical fiber preform by MCVD is disclosed. In the preform manufacturing apparatus, a cylindrical deposition tube receives a source gas through one end and discharges the source gas through the other end. A first heat source (262) is mounted to a guide and forms a first high temperature area (330) inside the deposition tube by heating the outer circumferential surface of the deposition tube. A second heat source (266) is mounted to the guide, apart from the first heat source by a predetermined distance along the length direction of the deposition tube, and forms a second high temperature area (333) inside the deposition tube by heating the outer circumferential surface of the deposition tube. A heat source mover moves the first and second heat sources (262,266), maintaining the distance between the first and second heat sources.
Abstract:
PURPOSE: An apparatus for modulating data is provided to form a modulation code for improving the DC-free performance by applying a multi-coding method to a weak DC-free modulation code. CONSTITUTION: An apparatus for modulating data includes a multiplexing unit(20), an encoding unit(40), and a selection unit(50). The multiplexing unit(20) multiplexes input data divided according to a constant length and provides multiplexed data streams by using the multiplexing information. The encoding unit(40) performs a weak DC-free RLL(Run Length Limited) modulation process for the multiplexed data streams in order not to use a DC control conversion table including additional bits. The selection unit(50) selects the code stream having the minimum quantity of DC components from the multiplexed and RLL-modulated code streams.
Abstract:
PURPOSE: An optical fiber block for minimizing the stress generation of an optical fiber is provided to minimize the occurrences of sharp bending generated around a boundary between an optical fiber alignment portion and a stress reduction depth portion, thereby minimizing the optical loss. CONSTITUTION: An optical fiber block(40) for minimizing the stress generation of an optical fiber, wherein the optical fiber block(40) aligns a planar wqveguide optical circuit and an optical fiber for use in a wavelength multiplexing communication system to combine therebetween, includes a silicon wafer(W) provided with an optical fiber alignment portion(42) and a stress reduction depth portion with a predetermined depth from the optical fiber alignment portion(42), a plurality of horizontal V-grooves(421) formed by using an etching process so as to align a plurality of bare optical fibers of a ribbon optical fiber on the optical fiber alignment portion(42) and a number of vertical V-grooves(422) for minimizing the generation of stress applied to the optical fibers aligned by forming on end portions of the horizontal V-grooves(421) at a predetermined depth.
Abstract:
PURPOSE: An apparatus for compensating for dispersion of optical fiber is provided to make a zero dispersion using a filter capable of adjusting a dispersion value. CONSTITUTION: An apparatus for compensating for dispersion of optical fiber includes an optical transmitter(100) for generating optical signals to be transmitted. A dispersion compensation optical fiber(110) compensates for the optical signals generated in the optical transmitter(100) in a given dispersion value. A circulator(120) receives the optical signals from the dispersion compensation optical fiber(110) to output it to a dispersion compensation filter(130). The dispersion compensation filter(130) adjusts the dispersion value of the optical signal from the dispersion compensation optical signal(110). An optical amplifier(140) amplifies the signal from the dispersion compensation filter(130). An optical receiver(160) receives the optical signal from the optical amplifier(140).
Abstract:
PURPOSE: An optical fiber subscriber network is provided to maximize the number of subscribers by assigning a plurality of intrinsic wavelength sets to each subscriber and using them as the physical paths of optical communication. CONSTITUTION: An optical fiber subscriber network is composed of a central office side(410), a subscriber side(420) comprising a plurality of subscribers(1-P), and an upstream/downstream optical fiber cable(440) provided as a communication path to transmit data between the central office side(410) and the subscriber side(420). The central office side(410) is provided with an ATM exchange(412), a plurality of optical transmitting parts(414), a wavelength division multiplexer(416) and an optical amplification part(418). The optical transmitting parts(414) converts electrical data, outputted from the ATM exchange(412), into optical signals and outputs the optical signals of each intrinsic wavelength band. The wavelength division multiplexer(416) combines the optical signals outputted from the optical transmitting parts(414) so as to carry them through one downstream optical fiber cable. The optical amplification part(418) amplifies the original signals in order to compensate loss generated during the transmission and distribution of the combined optical signals.