Precise broadband frequency modulated laser

1. An apparatus comprising:

a tunable laser having a plurality of drive inputs for affecting an optical frequency of light output by the laser, wherein the plurality of drive inputs have a corresponding plurality of different frequency response bands for changing optical properties of the tunable laser and a corresponding plurality of actuation ranges of optical frequencies affected;

a frequency sweep generator configured to drive at least one drive input of the plurality of drive inputs with a sweep signal that causes the tunable laser to output light with a time dependent optical frequency or phase spanning at least 1 gigaHertz of optical frequency bandwidth;

an optical detector;

a plurality of optical paths configured to direct light output by the laser onto the optical detector; and

a laser controller configured to provide a plurality of inputs to the plurality of drive inputs, each input of the plurality of inputs based on a detector signal output from the optical detector and a corresponding frequency response band of the plurality of different frequency response bands and a corresponding actuation range of the plurality of actuation ranges.

2. An apparatus comprising:

a tunable laser having a plurality of drive inputs for affecting an optical frequency of light output by the laser, wherein the plurality of drive inputs have a corresponding plurality of different frequency response bands for changing optical properties of the tunable laser and a corresponding plurality of actuation ranges of optical frequencies affected;

an optical detector;

a plurality of optical paths configured to direct light output by the laser onto the optical detector; and

a laser controller configured to provide a plurality of inputs to the plurality of drive inputs based on a detector signal output from the optical detector and the corresponding frequency response bands actuation ranges,

wherein:

the apparatus further comprises external to the tunable laser an optical actuator configured to affect the optical frequency of light transmitted into the plurality of optical paths based on a signal input to the optical actuator; and

the laser controller is further configured to provide the signal input to the optical actuator based on the detector signal output from the optical detector and a frequency response band and actuation range for the optical actuator.

3. An apparatus comprising:

a laser,

an optical detector;

a plurality of optical paths configured to direct light output by the laser onto the detector;

an optical actuator in an optical path between the laser and the plurality of optical paths, the optical actuator configured to affect the optical frequency of light transmitted into the plurality of optical paths based on a first signal input to the optical actuator; and

a laser controller configured to provide the first signal input to the optical actuator based on the detector signal output from the optical detector,

wherein

the optical actuator has an actuator frequency response band for changing optical properties of the light transmitted into the plurality of optical paths and an actuator actuation range of optical frequencies affected; and,

the laser controller is further configured to provide the first signal input to the optical actuator based on the actuator frequency response band and the actuator actuation range of the optical actuator.

4. An apparatus as recited in claim 3 , wherein:

the laser comprises a tunable laser having a drive input for affecting an optical frequency of light output by the tunable laser; and,

the laser controller is further configured to provide a second signal input to the drive input based on the detector signal output from the optical detector.

5. An apparatus as recited in claim 4 , wherein:

the drive input has a drive frequency response band for changing optical properties of light output by the tunable laser and a drive actuation range of optical frequencies affected; and,

the laser controller is further configured to provide the second signal input to the drive input based on the drive frequency response band and the drive actuation range of the drive input.

6. A method for producing a laser beam with constant rate of change over large bandwidth, comprising:

generating from a beam of a laser, a processed beam having a time varying intensity, the time variation of the processed beam's intensity being a function of the time rate of change of the frequency of the laser, further comprising

splitting the beam from the laser into first and second beam portions which traverse different optical paths with different travel times for a same optical frequency, and

combining said first and second beam portions after the first and second beam portions have traversed the different optical paths, wherein the processed beam comprises said combined beam portions;

deriving, from said time variation, a signal that is a function of the time rate of change of the frequency of the beam of the laser;

filtering the derived signal into a plurality of filtered signals in a corresponding plurality of actuation ranges for a corresponding plurality of actuators that affect a frequency of the beam of the laser; and

employing the plurality of filtered signals as loopback to the plurality of actuators to stabilize the rate of change of the frequency of the beam of the laser.

7. A method for producing a laser beam with desired time rate of change of optical frequency over large optical bandwidth, comprising:

generating a beam of a laser comprising a series of alternating increasing and decreasing optical frequencies of a desired large optical bandwidth;

generating from the beam of the laser, a processed beam having a time varying intensity, the time variation of the processed beam's intensity being a function of the time rate of change of the frequency of the laser, further comprising

splitting the beam of the laser into first and second beam portions which traverse different optical paths with different travel times for a same optical frequency, and

combining said first and second beam portions after the first and second beam portions have traversed the different optical paths, wherein the processed beam comprises said combined beam portions;

deriving, from said time variation, a signal that is a function of the time rate of change of the frequency of the beam of the laser; and

employing the derived signal as loopback to stabilize the rate of change of the frequency of the laser.

8. An apparatus comprising:

a tunable laser having a drive input for affecting an optical frequency of light output by the tunable laser wherein the drive input has a drive frequency response band for changing optical properties of light output by the tunable laser and a drive actuation range of optical frequencies affected;

an optical detector;

a plurality of optical paths configured to direct light output by the laser onto the detector;

an optical actuator in an optical path between the laser and the plurality of optical paths, the optical actuator configured to affect the optical frequency of light transmitted into the plurality of optical paths based on a first signal input to the optical actuator; and

a laser controller configured to provide the first signal input to the optical actuator based on the detector signal output from the optical detector and configured to provide a second signal input to the drive input based on the detector signal output from the optical detector and the drive actuation range of the drive input.