摘要:
Disclosed is a broadband light source for measurement using a seed-beam which can reduce the strength difference between the output lights per wavelength by heightening the strength of the output light corresponding to the L-band of the light source, and thus reduce the measurement error per wavelength. The broadband light source includes a seed-beam light source for outputting a seed-beam of a predetermined band of wavelength, a first optical coupler for combining the seed-beam and a pumping light and making a combined light incident to a front of a rare earth ion-doped optical fiber, a first pumping light source for providing the pumping light to the first optical coupler, a second optical coupler for making the input pumping light incident to a rear of the rare earth ion-doped optical fiber, a second pumping light source for providing the pumping light to the second optical coupler, and an output terminal for radiating the light outputted through the rear of the rare earth ion-doped optical fiber.
摘要:
A wavelength division multiplexing erbium doped fiber amplifier (WDM-EDFA) which outputs constant power per channel, and an amplification method thereof, are provided. The WDM-EDFA for amplifying received signal light of a plurality of channels which are multiplexed, includes a power control unit for generating dummy light whose output power is controlled according to a first control value, and controlling the power of received signal light by coupling the dummy light to the received signal light, an optical fiber amplification unit for amplifying signal light power-controlled by the power control unit, using pumping light generated according to a second control value, and a controller for supplying the first control value to the power control unit to obtain dummy light power corresponding to the difference between the power value of the received signal light and a predetermined target power value, and supplying the second control value to the optical fiber amplification unit to obtain pumping light power required to amplify the received signal light. Thus, a transient effect of the WDM-EDFAs, in which a plurality of channels are multiplexed and amplified, can be eliminated by controlling the power of incident signal light of added/dropped channels.
摘要:
A method for fabricating a thermally expanded core (TEC) fiber including the steps of arc-fusion splicing two optical fibers having different clad outer diameters, and cutting boundary surface between an optical fiber having a small clad outer diameter and an optical fiber having a large clad outer diameter of the two optical fibers to obtain the thermally expanded core (TEC) fiber. Also, the method further includes the step of polishing the cutting face of the optical fiber having a small clad outer diameter of the two cut optical fibers.
摘要:
A gain measuring apparatus of a multi-channel optical fiber amplifier for amplifying an input multi-channel optical signal of a predetermined wavelength range includes a plurality of optical signal sources for generating an optical signal, the number of optical signal sources being less than the number of channels of the multi-channel optical signal, in a wavelength range of the multi-channel optical signal, a probe optical signal source for generating a probe signal of a wavelength of which gain is subject to measurement, an optical multiplexer for multiplexing optical signals output from the optical signal sources and the probe optical signal source, an optical amplification portion for splitting the optical signals multiplexed by the optical multiplexer in an equal ratio and passing one optical signal of the split optical signal with amplification and the other optical signal of the split optical signal without amplification, and a measuring system for respectively measuring intensities of the amplified probe optical signal at the optical amplification portion and the probe optical signal that is not amplified at the optical amplification portion. When the gain of multi-channel erbium doped fiber amplifier is measured, the signal gain of each channel can be accurately measured using less optical signal sources than the number of light sources corresponding to each channel.
摘要:
An optical add-drop multiplexer (OADM) for adding and dropping wavelength groups for each node among multiplexed and input wavelength groups includes: a wavelength group demultiplexer for separating a plurality of input channels into groups of channels and dropping a channel group required for the node and passing the other groups of channels therethrough; a channel selector for selecting channels from the wavelength group output from the wavelength group demultiplexer and transmitting the selected channels to the area; a channel multiplexer for multiplexing the channels having the same wavelengths as those of the selected channels and input from the area into the wavelength group, and a wavelength group multiplexer for adding the wavelength group input from the channel multiplexer to the wavelength groups that have passed through the wavelength group demultiplexer. Wavelengths required for each node are set to a wavelength group, thereby reducing the time necessary in extending channel capacity or wavelengths in each node. Also, since only a channel selector is additionally installed in an OADM for wavelength extension, wavelength extension is facilitated and a WDM system can be constructed at a low cost. Such an OADM may be used in a wavelength division multiplexing (WDM) optical link.
摘要:
An arrayed waveguide grating (AWG) module monitors the quality of a wavelength division multiplexed (WDM) multi-channel optical signal without using a special measurer in a wavelength division multiplexing (WDM) system, and a device monitors a WDM optical signal using the AWG module. The AWG module includes an input waveguide, a first star coupler, an AWG unit, a second star coupler, and an optical power measurer. The input waveguide receives the WDM optical signal via an optical signal transmission medium. The first star coupler splits the power of the received WDM optical signal and transmits split optical signals to waveguides of the AWG unit. The AWG unit processes the split optical signals so that they have phase differences which are proportional to the difference between the lengths of the waveguides included in the AWG unit. The second star coupler focuses the optical signals received from the AWG unit at different locations by causing mutual interference between the received optical signals. The optical power measurer is directly connected to the second star coupler, and generates electrical signals depending on power values of the optical signals focused by the second star coupler. As a result, the characteristics of the optical signals of different channels constituting a WDM optical signal can be measured without a special measurer, and the spectrum of an optical signal with respect to the overall wavelength band can also be obtained. Also, the AWG module has a structure which is suitable for mass production.
摘要:
An optical attenuator using an isolator, and an optical communications system including the same, function to control the intensity of an input optical signal. The isolator comprises a Faraday rotator in which a rotation angle of polarization varies depending on the intensity of an applied magnetic field. As a result, the level of isolation of an optical signal changes in accordance with the rotation angle of polarization and an attenuated optical signal is outputted. A magnetic field generator generates a magnetic field having an intensity which is controlled by the intensity of current, and the generated magnetic field is applied to the isolator A power supply supplies current to the magnetic field generator and controls the intensity of the current. A magnetic core and a coil are installed on the optical isolator, and currents applied to the coil are controlled to adjust the intensity of the magnetic field which is formed on the isolator. Accordingly isolation of an optical signal is controlled, and the optical signal is attenuated. The optical attenuator is easily mounted on the system because of its small size, and can change the level of attenuation by controlling only the intensity of current.
摘要:
A method and apparatus for amplifying the optical signals of a C-band (1550 nm wavelength band) and a L-band (1580 nm wavelength band) in a wide-band optical fiber amplifier, wherein the incoming optical signals are separated into the 1550 nm wavelength band and the 1580 nm wavelength band by a WVDM optical coupler and respectively amplified by a C-band EDFA and a L-band EDFA A backward ASE generated by the C-band EDFA is fed back to the L-band EDFA by a circulator as a supplementary pumping light to the amplification of the optical signals of the 1580 nm wavelength band.
摘要:
A L-band(long-band) optical fiber amplifier is provided. The L-band optical fiber amplifier includes an optical fiber doped with a rare-earth element, at least one pumping light source for emitting pumping light to the optical fiber, a seed beam source for emitting a seed beam at a predetermined wavelength band, and a seed beam coupler disposed between an input terminal and the optical fiber, for coupling an input optical signal with the seed beam and feeding the coupled light forward to the optical fiber. By use of the seed beam, the L-band optical fiber amplifier improves gain flatness characteristics at wavelengths of an optical signal and increases amplification efficiency when the length of the optical fiber and the intensities of the optical signal and the pumping light are changed.
摘要:
An optical fiber amplifier including a first optical fiber doped with erbium and phosphorous, for amplifying signal light excited by the erbium, a second optical fiber connected to one end of the first optical fiber, doped with erbium and aluminum, and having a gain spectrum slope opposite to the first optical fiber according to population inversion of the erbium, for amplifying signal light output by the first optical fiber, a pumping laser source connected to another end of the first optical fiber, for exciting the erbium of the first and second optical fibers, and a light coupler for coupling pumping light from the pumping laser source to the signal light and outputting the resultant light to the first optical fiber. Two types of EDFs (erbium doped fibers) having different gain spectrums are used, such that the gain spectrum of each of the EDFs actively varies with the input signal light power or pumping light power. Thus, an entirely flat gain is kept.