| Patent application number | Description | Published |
|---|
| 20080232817 | Waveform shaping apparatus, optical transmission system, and waveform shaping method - A waveform shaping apparatus includes a quantum dot optical amplifier in which an amplification factor of input signal beams saturates if the optical power of the signal beams is equal to or greater than a predetermined value; and a quantum dot saturable absorber in which an absorption factor of the input signal beams saturates if the optical power of the signal beams is under a predetermined value. The quantum dot optical amplifier and the quantum dot saturable absorber are connected in series with a transmission path of the signal beams, and shape the waveform of the signal beams. Voltages applied to the quantum dot optical amplifier and the quantum dot saturable absorber, respectively, are adjusted based on the optical power of the signal beams. | 09-25-2008 |
| 20090010656 | Optical waveform measurement system and optical waveform measurement method - In an optical waveform measurement system, a phase comparator compares phases between an electric signal output from a PD and an electric signal output from a mixer, and outputs a signal having an amplitude proportional to the phase difference of the two electric signals to a VCO via an LPF, as an error signal. A BPF removes a jitter from the electric signal output from the VCO, and a sampling pulse light source outputs sampling light based on the electric signal with the jitter removed. An optical sampling gate samples signal light to be measured with sampling light output from a sampling pulse light source, and the sampled signal light to be measured is measured by an oscilloscope. | 01-08-2009 |
| 20090097854 | OPTICAL SIGNAL PROCESSING APPARATUS - An O/E conversion element converts an input NRZ optical signal into an electric signal. A clock recovery circuit recovers a clock signal from the electric signal obtained by the O/E conversion element. A phase modulator applies phase modulation to the NRZ optical signal, using the recovered clock signal. An intensity modulator applies intensity modulation to the NRZ optical signal, using the recovered clock signal. A dispersion medium compensates for a frequency chirp of an optical signal output from the intensity modulator. | 04-16-2009 |
| 20090207489 | OPTICAL PROCESSING DEVICE AND OPTICAL PROCESSING METHOD - An optical processing device includes: a light source that outputs second light having a first polarization state or a second polarization state in synchronization with the pulse timing of the pulse of first light; a first nonlinear medium that controls the polarization state of the first light pulse in accordance with the polarization state of the second light pulse, using a nonlinear effect; and a separator that outputs the first light pulse from the first nonlinear medium selectively to a first output path or a second output path in accordance with the polarization state controlled by the first nonlinear medium. In this device, the first nonlinear medium uses the nonlinear effect to compensate the level of each first light pulse output selectively to the first output path or the second output path by the separator, with each first light pulse receiving the energy of the second light pulse. | 08-20-2009 |
| 20100054753 | APPARATUS AND METHOD FOR STABILIZING POLARIZATION STATE - An apparatus includes: a polarizing beam splitter for splitting the input light into a first light and a second light and for outputting the first light and the second light into optical paths, respectively; a polarization rotator rotating polarized light of the light path by approximately 90 degree; a first path length adjuster adjusting a difference path length between the optical paths in order to be approximately equal to zero; a second path length adjuster adjusting a difference path length between the optical paths in order to be an integer multiple of a wavelength of the input light; an optical attenuator arranged adjusting a propagation loss of the optical path in order to approximately match the propagation losses of the optical paths; and an output element for combining the first light and the second light from the paths and for outputting the output light. | 03-04-2010 |
| 20100142959 | Optical waveform shaping method and optical waveform shaping apparatus - In an optical waveform shaping apparatus, a WDM signal light is amplified by a first optical amplifier, and thereafter, is input to a first nonlinear medium; a spectrum of the signal light of each wavelength is expanded due to SPM in the first nonlinear medium to thereby separate a signal component and a noise component; and for each spectrum, only a signal component on a short wavelength side is collectively extracted by an optical filter. Then, an output light of the optical filter is amplified by a second optical amplifier, and thereafter, is input to a second nonlinear medium, and the wavelength of each signal light is collectively shifted to a longer wavelength side due to self-frequency shifting in the second nonlinear medium, to thereby return the wavelength of each signal light to that for when each signal light contained in the WDM signal light has been input. As a result, the signal light of each wavelength contained in the WDM signal light can be collectively waveform shaped, and also, the wavelength of each signal light after waveform shaped can be precisely the same as that before waveform shaped. | 06-10-2010 |
| 20100220997 | OPTICAL SIGNAL PROCESSING DEVICE AND METHOD OF PROCESSING OPTICAL SIGNAL - An optical signal processing device for shaping a waveform of an optical signal, including: an intensity inversion wavelength converter configured to generate an intensity-modulated optical signal of a second wavelength obtained by inverting a signal intensity of an input intensity-modulated optical signal of a first wavelength; an optical coupler configured to multiplex the intensity-modulated optical signal of the first wavelength and the intensity-modulated optical signal of the second wavelength at a timing at which signal intensities of those signals become opposite; and an optical limiter configured to input coupled light output from the optical coupler, and suppress gain as power of the coupled light becomes higher. | 09-02-2010 |
| 20100221014 | OPTICAL FIBER TRANSMISSION SYSTEM AND METHOD - An optical fiber transmission system including: a first transmission-line optical fiber to input first wavelength signal light output from a transmitter, and to change a waveform of the signal light; an optical coupler to combine the first wavelength signal light that has been propagated through the first transmission-line optical fiber with second wavelength pumping light; an optical limiter to input coupled light output from the optical coupler, saturating a gain as power of the coupled light increases using a nonlinear optical medium, thereby suppressing an optical noise component included in the coupled light, and to output signal light including the first wavelength optical component obtained from the nonlinear optical medium; and a second transmission-line optical fiber to input to a receiver after signal light output from the optical limiter is input and a waveform change by the first transmission-line optical fiber in the signal light is compensated for. | 09-02-2010 |
