Optical: systems and elements – Optical modulator
Patent
1999-07-08
2000-08-08
Ben, Loha
Optical: systems and elements
Optical modulator
359245, 385 2, 385 3, 385 8, G02F 100
Patent
active
061010219
ABSTRACT:
According to the present invention, damage to a photo-detector disposed in clock signal extractor by means of an optical pulse having an optical power exceeding a rated value is prevented. A ring resonator generates a repetitive, high-frequency optical pulse. Optical branching circuit branches a portion of the optical pulse circulating through ring resonator, while optical branching circuit further branches a portion thereof to protective device. Pumping source generates an excitation light for exciting a rare-earth doped optical fiber. Optical multiplexer couples the optical pulse branched by optical branching circuit, and the excitation light. Upon excitation by means of the excitation light, rare-earth doped optical fiber amplifies and emits the incoming optical pulse. The optical power of the excitation light is adjusted such that the output of rare-earth doped optical fiber reaches a saturation power. Optical switch blocks the incoming optical pulse during the time period when pumping source is not emitting an excitation light, and during a fixed time period following the emission of the excitation light. In this manner, the entry of an excessively large optical pulse exceeding the saturation power into photo-detector at the time of starting up the power source is prevented. Optical attenuator attenuates the optical power of the optical pulse emitted from optical switch to an optical power which the photo-detector is capable of photo-detecting. Photo-detector converts the optical pulse emitted from protective device into an electronic signal; narrow band filter extracts a clock signal from the output of photo-detector; and electric amplifier amplifies the output of narrow band filter, and outputs a clock signal. Phase shifter adjusts the phase of this clock signal; electric amplifier amplifies the output of phase shifter, and outputs a clock signal to optical modulator. Optical modulator modulates the intensity of the light circulating through the ring resonator based on the clock signal, and generates an optical pulse.
REFERENCES:
patent: 4968110 (1990-11-01), Bulmer et al.
patent: 5917179 (1999-06-01), Yao
Ichikawa Akio
Iida Rikihiro
Kumagai Yoshihiro
Nakazawa Masataka
Yoshida Eiji
Ando Electric Co. Ltd.
Ben Loha
Nippon Telegraph & Telephone Corporation
LandOfFree
Optical pulse generator does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Optical pulse generator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical pulse generator will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1155929