Jds Uniphase Corporation

Lightwave Electronics Corporation

Lumentum Operations LLC

Werner H Wiechmann

Frank J Adams

Mark Alan Arbore

Jeffrey Dellert Kmetec

James J Morehead

Loren A Eyres

Jeffrey Gregg

The invention discloses an actively Q-switched laser with an intracavity nonlinear coupler in which a stable optical frequency converted output is generated. A Gain Fluctuation Insensitivity Condition is defined and described for several examples. The nonlinear coupler with a coupling level which satisfies this Condition permits stable laser operation with minimal interaction between pulses, even when the pulses are clipped by the Q-switch. Thus, the output pulse duration and repetition frequency of the disclosed laser can be varied over a large range substantially independent of laser gain level and dynamics. Second and third harmonic optical frequency conversion is demonstrated, although the disclosed laser is applicable to other optical frequency conversion regimes as well.

Stabilization of actively Q-switched lasers

Methods and apparatus for managing thermal loads on a laser gain medium and for boosting the output power of a diode pumped laser are disclosed. The short-term average pumping power to the gain medium is increased, to provide a burst of pumping energy to the laser gain medium. A subsequent short-term reduction in the average pumping power then allows the gain medium to cool to a desired state steady level. The average pumping power is then increased to maintain this steady state level until the next burst is desired. For example, a pulse of current may be applied to a laser diode at a first current level Ifor a first time interval &#x394;t, where Iexceeds a nominal current value Iby an amount &#x394;I. The current to the laser diode is reduced to a second current level Ifor a second time interval &#x394;t, where Iexceeds Iby an amount &#x394;I. To balance the thermal load on the diode an integral of &#x394;Iover the time &#x394;tis approximately equal in magnitude to an integral of &#x394;Iover the time &#x394;t. After applying the pulse of current at the first current level I, and before or after reducing the current to the second level I, the nominal current is applied to the laser diode for a third time interval &#x394;t.

Laser burst boosting method and apparatus

Pulse recovery times are reduced in a pulsed intracavity frequency-converted laser by operating the laser in a continuous-wave (c.w.) mode before operation in a Q-switched mode. C.w. light locally optically heats the frequency-conversion optics of the laser to facilitate phase-matching at the beginning of Q-switched operation. C.w. operation also reduces the amplitude of the first pulse of the subsequent firing sequence by expending population inversion accumulating in the gain medium. Operation in c.w. mode is initiated by ramping up the net optical gain in the laser cavity when the time elapsed since the latest emitted pulse exceeds 110% of the interpulse spacing prior to the latest pulse. Initiation of c.w. operation does not require external signals other than optionally a pulse trigger sequence from the user. Cavity optical losses may be increased immediately prior to the first pulse, for accumulating population inversion and increasing the first pulse to a desired level. Frequency doubling and tripling lithium triborate (LBO) crystals were used with a Nd-YAG solid state medium to generate ultraviolet light at 355 nm from infrared light at 1064 nm.

Pulse amplitude control in frequency-converted lasers

Growing community of inventors

San Jose, CA, United States of America

Werner H Wiechmann