摘要:
An optical communications system includes a plurality of optical fiber spans. An optical loss of one of the plurality of optical fiber spans is different from an optical loss of another one of the plurality of optical fiber spans. At least one of the plurality of optical fiber spans includes an optical loss that is greater than or equal to 35 dB and at least one of the plurality of optical fiber spans includes an optical loss that is less than 30 dB. An optical amplification system includes at least one discrete optical amplifier, at least one distributed optical amplifier, and an optical loss element. The optical amplification system has spectral gain that compensates for substantially all losses experienced by the optical signals propagating in the plurality of optical fiber spans.
摘要:
A multichannel light source wavelength and strength stabilizing apparatus and a method thereof are disclosed. The apparatus includes a first proportional/integrator for receiving an output signal from the error detector, detecting a value proportional thereto, integrating the detected proportional value, generating a signal corresponding to the optimum feedback circuit, and outputting to the temperature controller; a current controller for providing the current capable of controlling the light strength in accordance with the signal inputted to the light source and stabilizing the light strength; a second optical coupling unit for dividing the output signal from the first optical coupling unit; a photodetector for converting the strength of a light among the output signals from the second optical coupling unit into an electrical signal; and a second proportional/integration unit for detecting a proportional value of the output signal from the optical detector, integrating the detected proportional value, generating a signal corresponding to the optimum feedback circuit, and outputting to the current controller.
摘要:
A wavelength aligning apparatus using an arrayed waveguide grating (AWG), and particularly, to a wavelength aligning apparatus using an arrayed waveguide grating which is capable of aligning optical sources using a transmission characteristic of an arrayed waveguide grating in a wavelength alignment method. The apparatus includes a signal generator for applying a signal spaced-apart at a predetermined interval near a predetermined frequency to a bias current of the light source and dithering a central wavelength of each light source, an arrayed waveguide grating for providing a reference wavelength causing a variation difference from the central portion due to a dithering of the central wavelength, a temperature controller for determining a reference wave length by constantly maintaining a temperature of the arrayed waveguide grating, an optical fiber coupler disposed in an output terminal of the arrayed waveguide grating for dividing the signal into a transmission signal and an incoming signal, a plurality of locking amplifiers and a proportional/integration/differentiating unit for computing a bias current corresponding to the detected error signal, and a superposing unit for superposing the computed bias current and a signal from the signal generator for output to the laser diode driver.
摘要:
The present application describes methods and systems that improve the optical signal to noise ratio performance of an optical network without the need to vary the free spectral range associated with a differential interferometer. This is achieved by varying an electrical bandwidth of an electronic device associated with the receiver. For example, the electrical bandwidth may vary in inverse proportion to the combined effective optical bandwidth of the transmission line carrying the optical signal. The techniques described herein a applicable to a wide variety of modulation formats, including mPSK, DPSK, DmPSK, PDmPSK, mQAM, ODB, and other direct-detection formats. Using the techniques described herein, the optical signal to noise ratio and bit error ratio performance of the optical network is improved without the need to provide costly and complex differential interferometers whose free spectral range is variable.