Diffraction grating driven linear frequency chirped laser

An improved laser system including at least first and second lasers for emitting first and second output beams corresponding to an up-chirp signal and a down-chirp signal, respectively, each of said first and second lasers including a laser cavity having an optical path and an optical beam circulating along the optical path of each said laser, said laser system for generating both said up-chirp signal and said down-chirp signal simultaneously comprising:

• a wheel having a planar face disposed such that at least a portion of said face is disposed in each of said first and second laser cavities;
• diffraction grating means disposed radially on the face of said wheel;
• means for rotating said wheel;
• means for impinging the optical beams on said diffraction grating means as said wheel rotates and moves said grating means for producing said up-chirp signal and said down-chirp signal without any real change in the cavity length of said laser cavities;
• first and second output optical means at the output of said first and second lasers for passing a first output signal corresponding to one of said up-chirp signal and said down-chirp signal and a second output signal corresponding to the other of said up-chirp signal and said down-chirp signal, respectively;
• third output optical means for reflecting the second output signal from the second laser, a polarizing beamsplitter means disposed in the optical path at the output of the first laser for passing the first output signal therethrough;
• and
• a half waveplate means disposed in the path of the second output signal reflected from said third optical means at the output of said second laser for impinging the reflected second output signal onto the polarizing beamsplitter means and combining the second output signal with the first output signal to produce a combined output of the simultaneously generated up-chirp and down-chirp signals having orthogonal polarizations without interference between one another.

A system for generating a chirped laser signal comprising:

• a laser for outputting an output beam;
• said laser having a resonant cavity having an optical path,
• a generated optical beam that travels along said optical path within said resonant cavity;
• a circular wheel disposed in the optical path within said resonant cavity, said wheel having an outer peripheral rim portion;
• diffraction grating means disposed on the outer peripheral rim portion of said wheel;
• means for rotating said wheel;
• and
• means for impinging said generated optical beam on the diffraction grating means on the peripheral rim portion of said rotating wheel for shifting the frequency of the optical beam and generating said chirped laser signal without any real change in the resonant cavity length.

A system for generating a chirped laser signal comprising:

• a laser for emitting an output beam;
• said laser having a resonant cavity having an optical path,
• a generated optical beam that travels along said optical path within said resonant cavity;
• a circular wheel disposed in said resonant cavity, said wheel including at least one planar face;
• diffraction grating means disposed on said at least one planar face of said wheel as a series of radial lines carried thereby;
• means for rotating said wheel;
• and
• means for impinging said generated optical beam onto the diffraction grating means on the face of said rotating wheel for shifting the frequency of the optical beam and generating said chirped laser signal without any real change in the resonant cavity length.

A laser system for simultaneously generating both an up-chirp signal and a down-chirp signal comprising:

• a first laser means for generating a first output beam comprising one of said up-chirp signal and said down-chirp signal, said first laser means having a first resonant cavity and a first optical beam circulating within said first resonant cavity;
• a second laser means for generating a second output beam comprising the other of said up-chirp signal and said down-chirp signal, said second laser means having a second resonant cavity and a second optical beam circulating within said second resonant cavity;
• a wheel having an outer peripheral rim, a first portion of said outer peripheral rim being disposed in said first resonant cavity and a second portion of said outer peripheral rim being disposed in said second resonant cavity;
• a diffraction grating disposed on the outer peripheral rim of said wheel;
• means for rotating said wheel;
• said first optical beam impinging on the diffraction grating on said first portion of the outer peripheral rim of said rotating wheel and said second optical beam impinging on the diffraction grating on the second portion of said outer peripheral rim of said rotating wheel for generating said up-chirp signal and said down-chirp signal without any real change in the cavity length of said laser cavities;
• and
• optical means for combining said first and second output signals for simultaneously outputting both said up-chirp signal and said down-chirp signal.

A laser system for simultaneously generating both up-chirp and down-chirp signals comprising:

• a first laser means for generating a first output beam comprising one of said up-chirp and down-chirp signals, said first laser means having a first resonant cavity, a first optical beam traveling along the optical path of said first resonant cavity, and a first output coupling means for emitting said first output beam;
• a second laser means for generating a second output beam comprising the other of said up-chirp and down-chirp signals, said second laser means having a second resonant cavity, a second optical beam traveling along the optical path of said second resonant cavity, and a second output coupling means for emitting said second output beam;
• a wheel having a planar face, a portion of the planar face of said wheel being disposed in the first resonant cavity and another portion of the face of said wheel being disposed in the optical path of the second resonant cavity;
• diffraction grating means disposed as a plurality of radial lines on the face of said wheel;
• means for rotating said wheel;
• said first laser means impinging said first optical beam on the diffraction grating means on the first portion of the face of said rotating wheel and the second laser means impinging said second optical beam on the diffraction grating means on the second portion of the face of said rotating wheel for producing said up-chirp and said down-chirp signals without any real change in the cavity length of said laser cavities;
• and
• optical means for combining the up-chirp signal and down-chirp signal output for simultaneously outputting same.

A laser system for simultaneously generating both up-chirp and down-chirp signals, one of said signals having a first polarization nd the other of said signals having a polarization orthogonal thereto, said system comprising:

• a first laser means for generating a first output beam comprising one of said up-chirp and down-chirp signals, said first laser means having a first resonant cavity and an optical beam circulating within said first resonant cavity;
• a second laser means for generating a second output beam comprising the other of said up-chirp and down-chirp signals, said second laser means having a second resonant cavity and an optical beam circulating within said second resonant cavity;
• a wheel having at least a face surface and an outer peripheral rim surface, said wheel being oriented such that a first portion of one of said surfaces is operatively disposed in one of said first and second resonant cavities and another portion of said one of said surfaces is operatively disposed in the other of said first and second resonant cavities;
• a diffraction grating disposed on said one of said surfaces of said wheel;
• means for rotating said wheel;
• said first and second optical beam impinging on opposite ones of said first and second portions for generating said up-chirp and down-chirp signals without any real change in the cavity length of said laser cavities;
• optical means at the output of one of said first and second laser means for changing the polarization of one of said up-chirp and down-chirp signals to an orthogonal polarization;
• and
• means for combining said signals and simultaneously generating both said up-chirp signals and down-chirp signals without interference therebetween.

A method for generating a chirped laser signal comprising the steps of:

• providing a laser having a laser resonant cavity;
• generating an optical laser beam within said laser resonant cavity;
• carrying a diffraction grating on the outer peripheral rim of a wheel;
• positioning the wheel in the laser's resonant cavity;
• rotating said wheel;
• impinging the generated optical beam within said laser cavity on the rotating diffraction grating;
• and thereby
• chirping the laser's frequency for producing a chirped output signal without any real change in the cavity length of said laser cavity.

A method for generating at least one of an up-chirp and a down-chirp signal in a laser system including a laser for generating an output beam, said laser having a resonant cavity and a generated optical beam circulating along the optical path of said resonant cavity, said method including the steps of:

• providing a wheel;
• disposing a radially-oriented diffraction grating on one of the faces of said wheel;
• orienting the grating-bearing face of said wheel such that the diffraction grating is disposed in said resonant cavity;
• rotating the wheel;
• and
• impinging th generated optical beam on the diffraction grating carried by the face of the wheel to tune the longitudinal modes of the resonant and generate at least one of an up-chirp and down-chirp signal without any real change in the cavity length of said laser cavity.

A method for generating at least one of an up-chirp signal and a down-chirp signal in a laser system including a laser for outputting an output beam, said laser having a resonant cavity and a generated optical beam circulating within said cavity, said method comprising the steps of:

• disposing a diffraction grating on the outer peripheral rim of a wheel;
• orienting the outer peripheral rim of the wheel such that said diffraction grating is disposed in said laser cavity;
• rotating the wheel;
• and
• impinging the optical beam onto the diffraction grating carried on the outer peripheral rim of the rotating wheel for tuning the longitudinal modes of the resonator and generating said at least one of an up-chirp and a down-chirp signal without any real change in the cavity length of said laser cavity.

A method for generating a chirped signal in a laser system including a laser for generating a laser output beam, said laser having a resonant cavity, said method comprising the steps of:

• disposing a diffraction grating within said resonant cavity;
• moving said carrier so that said diffraction grating is moved in its own surface in a direction perpendicular to the lines of said diffraction grating;
• and
• impinging the laser beam on said diffraction grating to cause the longitudinal modes of the resonant to tune and said chirped signal to be generated without any real change in the cavity length of said laser cavity.

An improved laser system for generating an up-chirp signal or a down-chirp signal, said laser system including a laser for emitting an output beam, said laser having a laser cavity and an optical beam circulating along an optical path within said cavity, said laser system comprising:

• a diffraction grating disposed in the optical path within said cavity;
• planar means for carrying said diffraction grating;
• means for translating said carrying means so that said diffraction grating is moved in the plane of said diffraction grating in a direction perpendicular to the lines of said diffraction grating without any real change in the cavity length;
• and
• means for impinging the optical beam on the moving diffraction grating for generating said up-chirp signal or said down-chirp signal.

An improved laser system for generating an up-chirp signal or a down-chirp signal, said laser system including a laser for emitting an output beam, said laser having a laser cavity and an optical beam circulating along an optical path within said cavity, said laser system comprising:

• a diffraction grating disposed in the optical path within said cavity;
• cylindrical means for carrying said diffraction grating;
• means for rotating said carrying means so that said diffraction grating is rotated in a cylindrical path in a direction perpendicular to the lines of said diffraction grating without any real change in the cavity length;
• and
• means for impinging the optical beam on the rotating diffraction grating for generating said up-chirp signal or said down-chirp signal.

An improved laser system for generating an up-chirp signal or a down-chirp signal, said laser system including a laser for emitting an output beam, said laser having a laser cavity and an optical beam circulating along an optical path within said cavity, said laser system comprising:

• a radial diffraction grating disposed in the optical path within said cavity;
• planar means for carrying said diffraction grating;
• means for rotating said carrying means so that said radial diffraction grating is rotated about its center in the plane of said diffraction grating without any real change in the cavity length;
• and
• means for impinging the optical beam on the rotating diffraction grating for generating said up-chirp signal or said down-chirp signal.