METHOD AND EQUIPMENT FOR OPTICAL COMMUNICATION

• Main Author: YOKOGAWA SEIICHI
• Format: Patent
• Language: English
• Published: 10.07.2001
• Edition: 7
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

PROBLEM TO BE SOLVED: To reduce the influence of a certain type of optical communication to the other types of optical communications. SOLUTION: When the optical communication is carried out by using a subcarrier to the infrared rays, the direct current light is additionally emitted in a time T1 when no subcarrier exists. The electric power that drives a light emitting element to emit the direct current light is set equal to the electric power that drives the light emitting element in a time T0 when a subcarrier exists. Since the light emitting element is driven, even if the subcarrier does not exist, by the same electric power as that available when the subcarrier exists and can emit the direct current light, a base band spectrum of low frequency that is not needed for the data communication can be reduced. Furthermore, the unnecessary spectra spreading over and under a subcarrier and the unnecessary spectrum of a higher harmonic can be reduced by dulling the changing point of the direct current light that is additionally emitted or changing the subcarrier into a dull waveform or a sine wave.