Laser Tuning by spectrally dependent spatial filtering

A laser comprising a optical resonator, said optical resonator comprising:

• a) a pumped gain medium, wherein the gain medium is an electrically pumped semiconductor single mode waveguide;
• b) an acousto-optic tuning element wherein an optical beam circulating within said optical resonator passes through said tuning element as a zeroth order beam;
• and
• c) a grid fixing etalon;
• wherein said optical resonator is aligned such that radiation is emitted from said optical resonator at substantially a single emission wavelength which is selected by said tuning element;
• wherein said optical resonator is configured as a standing wave resonator;
• wherein the length of said gain medium is selected such that said gain medium has a free spectral range (FSR) which is substantially equal to the FSR of said grid fixing etalon divided by an integer.

A method for generating a laser beam comprising:

• a) pumping a gain medium positioned within an optical resonator, said optical resonator defining an intracavity beam path;
• b) passing light traveling on said beam path through a tunable spectral notch filter provided by a tuning element;
• and
• c) passing light traveling on said beam oath through a grid fixing etalon;
• d) emitting a portion of a beam reflected from said grid fixing etalon to provide an etalon signal;
• e) emitting a portion of a beam circulating on said beam path to provide a reference signal;
• f) deriving a normalized etalon signal from said etalon signal and said reference signal;
• and
• g) controlling the optical length of said beam path to hold said normalized etalon signal fixed to a predetermined value;
• wherein said optical resonator is aligned such that radiation is emitted from said optical resonator at substantially a single emission wavelength which is selected by said tuning element.

A method for generating a laser beam comprising:

• a) pumping a gain medium positioned within an optical resonator, said optical resonator defining an intracavity beam path;
• and
• b) passing light traveling on said beam path through a tunable spectral notch filter provided by a tuning element;
• c) emitting a monitor beam from said optical resonator;
• d) splitting said monitor beam into a first beam and a second beam;
• e) filtering said second beam with an optical filter having a linear dependence on wavelength;
• f) detecting said first beam at a first detector to provide a first signal;
• g) detecting said filtered second beam at a second detector to provide a second signal;
• and
• h) deriving a wavelength measurement from said first signal and said second signal;
• wherein said optical resonator is aligned such that radiation is emitted from said optical resonator at substantially a single emission wavelength which is selected by said tuning element.

A method for generating a laser beam comprising:

• a) pumping a gain medium positioned within an optical resonator, said optical resonator defining an intracavity beam path, wherein said gain medium comprises an electrically pumped semiconductor single mode waveguide, wherein said optical resonator is configured as a standing wave resonator;
• b) passing light traveling on said beam path through an acousto-optic tuning element in zeroth order so that said light is not frequency shifted;
• c) passing light traveling on said beam path through a grid fixing etalon
• wherein said optical resonator is aligned such that radiation is emitted from said optical resonator at substantially a single emission wavelength which is selected by said tuning element;
• wherein the length of said gain medium is selected such that said gain medium has a free spectral range (FSR) which is substantially equal to the FSR of said grid fixing etalon divided by an integer.