Patent ID: 7400659
Filing Date: 2008-07-15
Classification: H01S,H04N

Abstract:
1. A method for modulating the wavelength of an output beam of a semiconductor laser, comprising the steps of: receiving a first current into a gain section of the laser, said gain current being essentially constant; and receiving a second, pulsating current which is pulse width modulated into a DBR section of the laser, said DBR section being modulated using at least a three-current system, said three currents being combinations of at least one of an “on” current that generates a center wavelength of said output beam, and alternating first and second “off” currents, wherein said first current “off” generates an output beam of a first “off” wavelength that longer than said central wavelength and second “off” current generates an output beam of a second “off” wavelength that is shorter than said central wavelength, said first and second “off” currents having lower and higher current amplitudes relative to a current amplitude of said “on” current, respectively, wherein combinations of first verses second “off” currents into said DBR section are selected such that current induced thermal loading of said laser remains sufficiently constant throughout operation of said DBR section to substantially avoid center wavelength drift of the center wavelength generated by the “on” current.