Method for optical communications
First Claim
1. A method for optical telecommunications comprising a step of transmitting an optical signal through an optical path (1) of an optical fiber (2) in a plurality of optical paths (1) laid in the form of a cable from the transmission side, applying an external signal to the optical path (1) to modulate the optical signal being transmitted therethrough for the plane of polarization and receiving the optical signal at the receiving side to determine the presence or absence of a modulated optical signal, characterized in that the optical signal is modulated by continuous pulses (a) at the transmitting side and a predetermined number (n) of pulses (a) are extracted within a given period of time in synchronism at the receiving side so that the presence of a modulated optical signal is acknowledged only when (m) or more than (m) pulses (a) are received within a set period of time (n≧
- m), and further characterized in that the absence of a modulated optical signal is acknowledged even when the above defined number of pulses (a) are received within a set period of time if k or more than k (k≧
1) noise signals (b) are found between any successive two of the received pulses (a).
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Accused Products
Abstract
There is provided a method for optical telecommunications with which an optical signal modulated for the plane of polarization can be received for certain without lowering the threshold level and being affected by noises so that any optical telecommunications can be identified without fail. With the method, an optical signal is modulated by continuous pulses a at the transmitting side before transmission and a predetermined number (n) of pulses a are extracted within a given period of time in synchronism at the receiving side so that the presence of a modulated optical signal is acknowledged only when the number of pulses a received within the given period of time is smaller than the predetermined number (n) but greater than another predetermined number (m) (n≧m). This method may be so modified that the absence of a modulated optical signal is acknowledged even when the above defined number of pulses are received if k or more than k (k≧1) noise signals b are found between any successive two of the received pulses.
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Citations
1 Claim
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1. A method for optical telecommunications comprising a step of transmitting an optical signal through an optical path (1) of an optical fiber (2) in a plurality of optical paths (1) laid in the form of a cable from the transmission side, applying an external signal to the optical path (1) to modulate the optical signal being transmitted therethrough for the plane of polarization and receiving the optical signal at the receiving side to determine the presence or absence of a modulated optical signal, characterized in that the optical signal is modulated by continuous pulses (a) at the transmitting side and a predetermined number (n) of pulses (a) are extracted within a given period of time in synchronism at the receiving side so that the presence of a modulated optical signal is acknowledged only when (m) or more than (m) pulses (a) are received within a set period of time (n≧
- m), and further characterized in that the absence of a modulated optical signal is acknowledged even when the above defined number of pulses (a) are received within a set period of time if k or more than k (k≧
1) noise signals (b) are found between any successive two of the received pulses (a).
- m), and further characterized in that the absence of a modulated optical signal is acknowledged even when the above defined number of pulses (a) are received within a set period of time if k or more than k (k≧
Specification
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- Resources
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Current AssigneeFurukawa Electric Company Limited
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Original AssigneeFurukawa Electric Company Limited
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InventorsOhgoshi, Haruki, Fujisaki, Akira, Nimura, Hijiri
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Primary Examiner(s)Boudreau, Leo
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Assistant Examiner(s)NEGASH, KINFE MICHAEL
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Application NumberUS08/449,945Time in Patent Office544 DaysField of Search359/110, 359/158, 359/173, 359/183-184, 356/73.1, 375/257, 375/287, 375/288, 375/317, 250/227.17US Class Current398/30CPC Class CodesH04B 10/07 Arrangements for monitoring...
