System and method for generating a frequency modulated linear laser waveform

A frequency modulated laser waveform generating system comprising:

• a single frequency laser configured for producing a laser output signal having a single frequency having a narrow linewidth defining a sine wave centered at ωo;
• an electro-optical modulator coupled to the laser and configured for receiving the laser output signal from the laser;
• an electric ramp generator coupled to the electro-optical modulator and configured for generating a linear ramp having a frequency chirp with a bandwidth B between the range of 300 MHz and 3.0 GHz over a time period T between the range of 0.01 msec and 0.20 msec, a modulation offset frequency ωm between the range of 5.0 GHz and 30 GHz, and a deviation less than or equal to 71 Khz, wherein the linear ramp is configured for controlling the electro-optical modulator to modulate the laser output signal to define a modulated waveform;
• and
• a band-pass optical filter coupled to the electro-optical modulator and configured for receiving the modulated waveform and for filtering out harmonic frequencies created by the electro-optical modulator during modulation of the laser output signal to define a pure filtered modulated waveform;
• and
• an optical circulator interconnecting the electric ramp generator and the band-pass optical filter and having an input configured for receiving the modulated waveform from the electric ramp generator, an output/input configured for sending and receiving the modulated waveform to and from the band-pass optical filter, and an output leg configured for transmitting the pure filtered modulated waveform;
• wherein the band-pass optical filter includes a bandwidth BW greater than the modulation bandwidth B and less than the modulation offset frequency ωm, and is centered at the frequency of the laser output signal ωo plus the modulation offset frequency ωm.

A method of generating a laser frequency modulated waveform, the method comprising:

• generating a laser output signal having an ultra narrow linewidth defining a sine wave;
• generating a linear ramp having a frequency chirp with a bandwidth B over a time period T, and a modulation offset frequency ωm, wherein the linear ramp includes a deviation less than or equal to 71 Khz;
• modulating the laser output signal from the single frequency laser with an electro-optical modulator driven by the linear ramp to define a linear triangular modulated waveform;
• and
• filtering the linear triangular modulated waveform from the electro-optical modulator with a band-pass optical filter to remove harmonic frequencies in the linear triangular modulated waveform created by the electro-optical modulator during modulation of the laser output signal to produce a pure filtered modulated waveform;
• wherein the band-pass optical filter includes a bandwidth BW greater than the modulation bandwidth B and less than the modulation offset frequency ωm, and is centered at a frequency of the laser output signal ωo plus the modulation offset frequency ωm;
• and
• wherein the modulation offset frequency a of the linear ramp is between the range of 5.0 GHz and 30 GHz, and the bandwidth B of the linear ramp is between the rang of 300 MHz and 3.0 GHz over a period T between the range of 0.01 msec and 0.20 msec.