Patent application number | Description | Published |
20080240180 | OPTICAL FM SOURCE BASED ON INTRA-CAVITY PHASE AND AMPLITUDE MODULATION IN LASERS - A laser is disclosed including a gain section having a distributed feedback grating imposed thereon. An absorption section is embedded in the gain section such that the first and second portions of the distributed feedback grating extend on either side of the electro-absorption section. A controller imposes a substantially DC bias signal on the first and second gain electrodes and imposes a modulation signal encoding digital data on the modulation electrode to generate a frequency modulated signal. In some embodiments, the first and second portions are biased above the lasing threshold and the absorption section is modulated below the lasing threshold to modulate loss in the absorption section. | 10-02-2008 |
20080247763 | CHIRPED LASER WITH PASSIVE FILTER ELEMENT FOR DIFFERENTIAL PHASE SHIFT KEYING GENERATION - A method for generating D-N-PSK optical signals is disclosed wherein a laser is modulated to generate optical signal pairs including phase modulated and fixed phase portions, the phase modulated portions having a frequency encoding one or more data symbols and the fixed phase portion having a carrier frequency and a phase corresponding to the immediately preceding phase modulated portion. The output of the laser is passed through an optical spectrum reshaper having a transmission function chosen to attenuate a plurality of the phase modulated portions relative to the fixed phase portions. The phase modulated portions may have N frequency levels located on either side of the carrier frequency. One of the N frequency levels may be equal to the carrier frequency. | 10-09-2008 |
20080247765 | POWER SOURCE FOR A DISPERSION COMPENSATION FIBER OPTIC SYSTEM - This invention generally relates to an optical filter for a fiber optic communication system. An optical filter may be used, following a directly modulated laser source, and converts a partially frequency modulated signal into a substantially amplitude modulated signal. The optical filter may compensate for the dispersion in the fiber optic transmission medium and may also lock the wavelength of the laser source. | 10-09-2008 |
20090016740 | METHOD AND APPARATUS FOR COMPENSATING FOR FIBER NONLINEARITY IN A TRANSMISSION SYSTEM - A transmitter includes a frequency modulated laser. An optical spectrum reshaper (OSR) is positioned to receive the frequency modulated signal and has a transmission function effective to convert the frequency modulation to amplitude modulation. An optical fiber channel has a first end positioned to receive the filtered signal and a second end proximate a receiver. A filter is positioned between the second end and the receiver and has a peak transmission frequency thereof located on a transmission edge of the OSR, such as at a peak logarithmic derivative value of the transmission function of the optical spectrum reshaper. In some embodiments a first OSR is positioned to receive the frequency modulated signal and configure to output a filtered signal wherein high frequency portions are more attenuated than low frequency portions. A second OSR at the receiver attenuates the low frequency portions substantially more than the high frequency portions. | 01-15-2009 |
20090041073 | DBR LASER WITH IMPROVED THERMAL TUNING EFFICIENCY - A distributed Bragg reflector (DBR) includes a base substrate and a gain medium formed on the base substrate. A waveguide positioned above the base substrate in optical communication with the gain medium and defines a gap extending between the base substrate and the waveguide along a substantial portion of the length thereof The waveguide having a grating formed therein. A heating element is in thermal contact with the waveguide and electrically coupled to a controller electrically configured to adjust optical properties of the waveguide by controlling power supplied to the heating element. | 02-12-2009 |
20090060526 | OPTICAL FM SOURCE BASED ON INTRA-CAVITY PHASE AND AMPLITUDE MODULATION IN LASERS - An optical transmitter is discloses having a gain section and a phase section. The phase section is modulated to generate a frequency modulated signal encoding data. The frequency modulated signal is transmitted through an optical spectrum reshaper operable to convert it into a frequency and amplitude modulated signal. In some embodiments, a driving circuit is coupled to the phase and gain sections is configured to simultaneously modulate both the phase and gain sections such that the first signal is both frequency and amplitude modulated. | 03-05-2009 |
20090074020 | DBR laser with improved thermal tuning effciency - A distributed Bragg reflector (DBR) includes a base substrate and a gain medium formed on the base substrate. A waveguide positioned above the base substrate in optical communication with the gain medium and defines a gap extending between the base substrate and the waveguide along a substantial portion of the length thereof. The waveguide may have a grating formed therein. A heating element is in thermal contact with the waveguide and electrically coupled to a controller configured to adjust optical properties of the waveguide by controlling power supplied to the heating element. | 03-19-2009 |
20100279447 | DBR LASER WITH IMPROVED THERMAL TUNING EFFICIENCY - A distributed Bragg reflector (DBR) includes a base substrate and a gain medium formed on the base substrate. A waveguide positioned above the base substrate in optical communication with the gain medium and defines a gap extending between the base substrate and the waveguide along a substantial portion of the length thereof. The waveguide having a grating formed therein. A heating element is in thermal contact with the waveguide and electrically coupled to a controller electrically configured to adjust optical properties of the waveguide by controlling power supplied to the heating element. | 11-04-2010 |
20100311195 | DBR Laser with Improved Thermal Tuning Efficiency - A distributed Bragg reflector (DBR) includes a base substrate and a gain medium formed on the base substrate. A waveguide positioned above the base substrate in optical communication with the gain medium and defines a gap extending between the base substrate and the waveguide along a substantial portion of the length thereof. The waveguide may have a grating formed therein. A heating element is in thermal contact with the waveguide and electrically coupled to a controller configured to adjust optical properties of the waveguide by controlling power supplied to the heating element. | 12-09-2010 |