Tunable blue laser diode

A frequency-converting, diode laser device comprising,

• a semiconductor laser of the type including a grating reflector for providing optical feedback at a first wavelength within a resonant optical cavity of said laser, the laser emitting a light beam or said first wavelength, said laser including means for tuning said first wavelength,
• a nonlinear frequency converting material optically coupled to said laser to receive said light beam and oriented for carrying out frequency conversion of said light beam received from said laser, said nonlinear frequency converting material characterized by a temperature-dependent resonance wavelength band for which light of a wavelength that coincides with said resonance wavelength band is efficiently converted by said material to light of a corresponding second wavelength, and
• temperature control means in thermal communication with said nonlinear frequency converting material for setting a temperature of said nonlinear frequency converting material to correspond to a selected resonance wavelength band with a desired corresponding second wavelength,
• said means for tuning said first wavelength of said laser setting said first wavelength to coincide with said selected resonance wavelength band of said nonlinear frequency converting material, whereby said light beam of said first wavelength emitted from said laser is converted to an output beam of said desired corresponding second wavelength.

A laser device comprising,

• a fiber amplifier having a single mode core, an input end and an output end,
• waveguide means at the output end of the fiber amplifier for doubling the frequency of light received therefrom and delivering an output beam,
• first, second and third semiconductor lasers having output beams directed at the input end of the fiber amplifier, the first and second lasers producing single mode first and second beams of light at two different frequencies, guided and amplified in the core of the fiber amplifier then doubled in the waveguide means, and She third laser producing a multimode third beam guided in the cladding of the fiber amplifier and having an optical power that pumps the fiber amplifier, and
• a time division multiplexer connected to the first and second lasers for allowing one of the first and second beams, then the other, into the waveguide means.

A method of making a monolithic frequency doubled laser comprising,

• forming a diode laser, the laser having a characteristic emission wavelength,
• forming a frequency converting waveguide, the frequency converting waveguide characterized by a resonant wavelength that is dependent upon an effective refractive index of said waveguide,
• annealing said frequency converting waveguide while monitoring the resonant wavelength of the frequency converting waveguide, said annealing causing a change in said effective refractive index and a consequent change in said resonant wavelength of said frequency converting waveguide, said annealing being carried out until a desired resonant wavelength of said frequency converting waveguide substantially matching said emission wavelength of said diode laser is reached, and
• mounting both said diode laser and said frequency converting waveguide on a common temperature-controlled submount, such that said diode laser is optically coupled to said frequency converting waveguide.

A laser device comprising,

• a laser oscillator having a first resonant frequency,
• a nonlinear optical waveguide means for converting the laser frequency to a second frequency, the waveguide having a second selectable resonant frequency,
• means to optically couple light between said laser and said waveguide, and
• means for tuning the first and second resonant frequencies at different rates so that said first and second resonant frequencies are phase matched for efficient frequency conversion.