摘要:
The present invention relates to an optical fiber telecommunication system and more in particular to an optical telecommunication system having a high loss transmission line. It relates also to an optical fiber amplifier doped with a rare earth, such as erbium, for use in said system. The optical fiber telecommunication system comprising:
a transmission station (104) producing at least one transmission optical signal in a predetermined wavelength band carrying the information; a receiving station (108) for receiving said transmission optical signal; an optical fiber line (106) connecting said transmission station and said receiving station, and at least one optical fiber amplifier (105) connected along said line for amplifying said transmission optical signal, said amplifier having a total optical output power greater than 20dBm.
The optical fiber amplifier for amplifying a transmission optical signal comprising:
a first stage and a second stage; an isolator (8) placed between the first stage and the second stage; in which the second stage comprises:
an erbium doped fiber; pump means comprising two pump sources (10,11) at different wavelengths in a second stage pump wavelengths band; a WDM coupling means coupling said different wavelengths as a composite second stage pump signal; a coupler (13) coupling said composite second stage pump signal and said transmission optical signal to said erbium doped fiber.
摘要:
An amplification circuit for amplifying wavelength-division-multiplexed (WDM) optical signals in a fiber-optic network is presented. The amplification circuit amplifies WDM signals propagating simultaneously in both directions through a fiber-optic link with a single unidirectional optical amplifier.
摘要:
An improved four-port dichroic WDM, for use in a multiwavelength, bi-directional optical amplifier, having a dichroic filter for substantially reflecting a first wavelength band input to the WDM to an output of the WDM for the first wavelength band and for substantially transmitting a second wavelength band input to the WDM to an output of the WDM for the second wavelength band, in which some of a first 3dB wavelength in the first wavelength band is transmitted by the filter and some of a second 3 dB wavelength in the second wavelength band is reflected by the filter, includes another dichroic filter having a filter function different than the filter function of the WDM filter providing an insertion loss for the first or the second 3 dB wavelengths sufficient to reflect and transmit, respectively, substantially all of the first and second 3 dB wavelengths. Additional dichroic filters for suppressing 3 dB light are used to prevent Q-switching in an optical gain cavity in a multiwavelength, bi-directional optical amplifier formed by a reflection point in an optical path connected to the amplifier.
摘要:
An optical amplifier achieves multistage amplification with a four port optical circulator (1) with fiber amplifiers (3,5,7) and Faraday rotators and mirrors (15,17) connected to at least two of the ports (B,C). The fiber amplifiers (3,7) permit the signal to pass through the fiber amplifiers twice.
摘要:
An optical telecommunication system comprising means (37, 38, 39, 40) for generating optical signals of different wavelengths, an optical-fibre line with amplifying means (45, 45', 45'', 45'''), a pre-amplifier (47), and receiving means (54, 55, 56, 57), wherein the pre-amplifier (47) comprises an optical waveguide (5,7,9) doped with a rare earth material, differential-attenuation means (8) located at a first position along the doped waveguide and capable of causing an attenuation in the signal band which is greater than the attenuation caused at the pumping wavelength, and filtering means (6) located at a second position and adapted to attenuate by a value higher than a predetermined minimum, the spontaneous emission in a wavelength band contiguous with the signal band. The position and attenuation of the differential-attenuation means and filtering means and the wavelength band are selected in a functional relation with respect to each other in order to limit the output power variations from the pre-amplifier.
摘要:
An optical amplifier amplifying a received optical signal, comprising:
a) a pumping light source emitting a pumping light beam; b) an optical fiber, doped with a rare earth element, having an input and an output; c) a first optical coupler for introducing a received optical signal and the pumping light beam to the input of said optical fiber; d) an optical receiver for receiving the received optical signal amplified resulting from propagation through the optical fiber and output from the output of said optical fiber; and, e) an optical isolator for preventing the received optical signal from propagating in a direction from said receiver to the output of said optical fiber; and An optical transmission system for transmitting an optical signal, comprising:
a) a first terminal station for transmitting an optical signal to an optical fiber line; b) a second terminal station, having an optical receiver, for receiving the optical signal; c) an optical amplifier, optically connected to the optical fiber line, for amplifying the optical signal from the optical fiber, including, an rare earth element doped optical fiber having an input and an output; means for receiving the optical signal from the optical fiber line and for inputting the optical signal to the input of said rare earth element doped optical fiber; a pumping light source, optically coupled to either the input or the output of the rare earth element doped optical fiber, emitting a pumping light beam introduced to either the input or the output of the rare earth element doped optical fiber; means for inputting the optical signal amplified resulting from propagation through the optical fiber to the optical receiver and for preventing the the optical signal from propagating in a direction from said optical receiver to the output of said optical fiber.
摘要:
2.1 Es soll eine optische Übertragungseinrichtung für die genannte Übertragung optischer Signale angegeben werden, mit der die durch nichtlineare Effekte verursachte Leistungsgrenze in Bezug auf den Datendurchsatz nach oben verschiebbar ist. 2.2 Dazu wird eine optisch verstärkend wirkende dotierte Faser verwendet, in die Pumpstrahlung zum Pumpen einkoppelbar ist, wobei eine den Grad der optischen Verstärkung bestimmende Konzentration des Dotierstoffes in der Faser über der Länge der Faser ein derartiges Profil aufweist, daß ein Signalpegel der in die Faser eingekoppelten optischen Signale beim Durchgang durch die gepumpte Faser in wenigstens einer Übertragungsrichtung konstant bleibt oder zumindest einen im Vergleich zur ungepumpten Faser verminderten Abfall des Signalpegels aufweist. 2.3 Anwendung für leistungsfähige Weitverkehrs-Übertragungsstrecken, Unterseekabel.
摘要:
Disclosed is a fiber amplifier system including a gain fiber having a single-mode core doped with active dopant ions capable of producing stimulated emission of light at wavelength λ s when pumped with light of wavelength λ p . Spliced to the gain fiber is a light-attenuating fiber having a core containing a dopant that attenuates light of wavelength λ p but not λ s . The amplifier is conventionally employed in a system including an incoming telecommunication fiber for introducing light of wavelength λ s into an end of the gain fiber, the amplified signal being connected to an outgoing telecommunication fiber. The system further includes a pump source for introducing light of wavelength λ p into an end of the gain fiber. Elements of the system can be arranged for forward pumping, counter pumping and dual ended pumping. Various interconnection schemes are disclosed for forming a series arrangement including the gain fiber, the attenuating fiber and the outgoing fiber.