Patent application number | Description | Published |
20080226294 | Passive optical network system and method of data transmission in the passive optical network - Regarding the passive optical network (PON) system of the present invention, in an OLT, data of different bit rates is framed, and framed data rows are subjected to FEC encoding processing without changing the line up of the data, and a check bit is added to the end of the frame, and an optical signal that has been modulated in accordance with the data row to which the check bit has been added is transmitted to the optical transmission line. Then in an ONU that corresponds to a high speed bit rate to which an optical signal from the OLT has been applied via a power splitter, forward error correction of the reception data is performed. As a result in a PON system in which data of different bit rates coexist, the minimum reception rate of a high speed ONU can be improved without having an influence on a low speed ONU. | 09-18-2008 |
20080253568 | Optical transmission device, scrambling method, and descrambling method - A first header-attaching unit attaches to data of a low speed bit rate A, a header of the bit rate A. A second header-attaching unit attaches the header of the bit rate A to data of a high speed bit rate B. A combining unit combines outputs of the first and the second header-attaching units. A low speed scrambling unit performs a scrambling process on combined data by using a clock corresponding to the bit rate A. A high speed scrambling unit performs a scrambling process on the data of the bit rate B by using a clock corresponding to the bit rate B. During a timing corresponding to the bit rate A in the frame, a selector selects an output of the low speed scrambling unit. During a timing corresponding to the bit rate B in the frame, the selector selects an output of the high speed scrambling unit. | 10-16-2008 |
20090034964 | Communication apparatus communicating with different bit rates - In order to allow bit-interleaved-parity calculation to be easily performed while maintaining compatibility with an existing system during transmission of data having mixed bit rates, header information of a first bit rate is added to data of the first bit rate and data of a second bit rate, time-division multiplexing is performed on the header-information-added data signals to generate a data string and a frame header is added thereto to generate a frame signal, parities of the frame signal that is sequentially generated are determined, parity bits for parity checking for the data signals of the first bit rate and the data signals of the second bit rate are inserted into the frame signal, based on a result of the parity calculation. | 02-05-2009 |
20090304329 | OPTICAL-SWITCH TESTING APPARATUS, OPTICAL-SIGNAL SWITCHING APPARATUS, OPTICAL-SWITCH TESTING METHOD, AND CONTROL METHOD FOR OPTICAL-SIGNAL SWITCHING - A light source supplies optical signal to an optical switch and a detector detects light receiving level. A control unit changes a deflection control amount for changing an angle of a tilt mirror, and outputs the deflection control amount to a driving unit. When an input and an output ports are same, optical offset of the tilt mirror is calculated based on optimal angle at which the light detector detects an optimal point of the light receiving level. Whenever the input and the output port are different, a structure parameter of the tilt mirror is calculated based on the optical offset and the optimal angle. The optical offset and the structure parameter are stored in a memory as a test result. | 12-10-2009 |
20100195183 | Optical switching apparatus and optical switching method - An optical switching apparatus changes an angle of a movable mirror reflecting light input to the optical switching apparatus and performs switching control for switching an output port that outputs the light reflected by the movable mirror. The optical switching apparatus includes an acquiring unit that acquires intensity information concerning the light output from the output port; a controller that based on the intensity information acquired by the acquiring unit and by adjusting the angle of the movable mirror, performs intensity control of the light output; a detector that based on the intensity information, detects a fluctuation greater than a predetermined fluctuation amount of the light output; and a suspending unit that suspends the intensity control by the controller, if the detector detects the fluctuation. | 08-05-2010 |
20100303407 | OPTICAL SWITCH AND METHOD FOR CONTROLLING OPTICAL SWITCH - An optical switch includes a mirror to reflect an input light; a controller to generate a control signal representing a target rotation angle of the mirror; a generator to generate a low-frequency signal; an adder to superimpose the low-frequency signal on the control signal; a driver to drive the mirror with a drive voltage corresponding to the control signal on which the low-frequency signal is superimposed; a detector to detect a frequency component or a harmonic component of the low-frequency signal included in an output light reflected by the mirror; and a correction unit to correct the control signal based on the detection result by the detector. The generator determines an amplitude of the low-frequency signal according to the target rotation angle. | 12-02-2010 |
20130058656 | OPTICAL TRANSMISSION DEVICE, SCRAMBLING METHOD, AND DESCRAMBLING METHOD - A first header-attaching unit attaches to data of a low speed bit rate A, a header of the bit rate A. A second header-attaching unit attaches the header of the bit rate A to data of a high speed bit rate B. A combining unit combines outputs of the first and the second header-attaching units. A low speed scrambling unit performs a scrambling process on combined data by using a clock corresponding to the bit rate A. A high speed scrambling unit performs a scrambling process on the data of the bit rate B by using a clock corresponding to the bit rate B. During a timing corresponding to the bit rate A in the frame, a selector selects an output of the low speed scrambling unit. During a timing corresponding to the bit rate B in the frame, the selector selects an output of the high speed scrambling unit. | 03-07-2013 |
20140212136 | OPTICAL TRANSMITTER AND MODULATED OPTICAL SIGNAL GENERATING METHOD - An optical transmitter includes: an optical modulator including a first modulation unit and a second modulation unit respectively configured to propagate a first optical signal and a second optical signal that are obtained by splitting input light; a signal generator configured to generate a first drive signal and a second drive signal that are respectively supplied to the first modulation unit and the second modulation unit; a phase controller configured to control a phase difference between the first optical signal and the second optical signal in the optical modulator; and a phase difference detector configured to detect the phase difference between the first optical signal and the second optical signal controlled by the phase controller. The signal generator generates the first drive signal and the second drive signal based on the phase difference detected by the phase difference detector. | 07-31-2014 |
20140328588 | OPTICAL COMMUNICATION SYSTEM, OPTICAL TRANSMITTER, AND OPTICAL RECEIVER - An optical communication system includes an optical transmitter, and an optical receiver connected via a transmission line to the optical transmitter, in which system the optical transmitter transmits a continuous-wave light signal that enables beat detection when combined with a local oscillator signal in the optical receiver, and the optical receiver acquires a beat waveform through digital sampling by detecting the light signal using the local oscillator signal, performs frequency analysis on digitally sampled data having the beat waveform prior to demodulation, and controls the local oscillator frequency based upon the beat frequency. | 11-06-2014 |