Electrically controllable collimator in a laser resonator

A laser, comprising:

• a laser cavity;
• a gain medium;
• a semitransparent mirror, said gain medium and said semitransparent mirror are disposed on opposite sides of said laser cavity;
• a control circuit;
• and
• a collimator having a first electrostatically controllable liquid lens with a first optical axis and a second electrostatically controllable liquid lens with a second optical axis aligned with the first optical axis.

A transmitter for an optical data network, the transmitter comprising:

• a laser, containing:
• a laser cavity;
• a gain medium;
• a semitransparent mirror, said gain medium and said semitransparent mirror are disposed on opposite sides of said laser cavity;
• a control circuit;
• and
• a collimator having a first electrostatically controllable liquid lens with a first optical axis and a second electrostatically controllable liquid lens with a second optical axis aligned with the first optical axis.

An optical data transmission device, comprising:

• a heterodyne receiver;
• and
• a transmitter, containing:
• a laser including a laser cavity, a gain medium, a semitransparent mirror, said gain medium and said semitransparent mirror are disposed on opposite sides of said laser cavity, a control circuit and a collimator having a first electrostatically controllable liquid lens with a first optical axis and a second electrostatically controllable liquid lens with a second optical axis aligned with the first optical axis;
• an optical reference source adapted to provide an optical reference signal, said optical reference source being an input signal of said heterodyne receiver;
• an optical mixer adapted to mix the optical reference signal and an output signal of said laser and to thereby generate an intermediate frequency signal;
• and
• a local reference source adapted to provide a local reference frequency, wherein said control circuit of said laser is adapted to compare the intermediate frequency with the local reference frequency, and to control said collimator to increase a phase when an output frequency is higher than the local reference frequency and to decrease a phase when the output frequency is lower than the local reference frequency.

An optical data transmission device, comprising:

• a heterodyne receiver;
• and
• a transmitter, containing:
• a laser including a laser cavity, a gain medium, a semitransparent mirror, said gain medium and said semitransparent mirror are disposed on opposite sides of said laser cavity, a control circuit and a collimator having a first electrostatically controllable liquid lens with a first optical axis and a second electrostatically controllable liquid lens with a second optical axis aligned with the first optical axis;
• an optical reference source adapted to provide an optical reference signal, said optical reference source being an input signal of said heterodyne receiver;
• an optical mixer adapted to mix the optical reference signal and an output signal of said laser and to thereby generate an intermediate frequency signal, said optical mixer is a photo diode for receiving an optical data signal of said heterodyne receiver;
• a local reference source adapted to provide a local reference frequency, wherein said control circuit of said laser is adapted to compare the intermediate frequency with the local reference frequency, and to control said collimator to increase a phase when an output frequency is higher than the local reference frequency and to decrease the phase when the output frequency is lower than the local reference frequency;
• a monitor diode adapted to provide a feedback signal containing information about an amplitude of the output signal of said laser, wherein said control circuit is adapted to control a focal length of said collimator such that an amplitude of the output signal of said laser reaches a maximum.

A communications method, which comprises the steps of:

• providing an optical data transmission device having a heterodyne receiver and a transmitter, the transmitter containing:
• a laser including a laser cavity, a gain medium, a semitransparent mirror, said gain medium and said semitransparent mirror are disposed on opposite sides of said laser cavity, a control circuit and a collimator having a first electrostatically controllable liquid lens with a first optical axis and a second electrostatically controllable liquid lens with a second optical axis aligned with the first optical axis;
• an optical reference source adapted to provide an optical reference signal, the optical reference source being an input signal of the heterodyne receiver;
• an optical mixer adapted to mix the optical reference signal and an output signal of the laser and to thereby generate an intermediate frequency signal;
• a local reference source adapted to provide a local reference frequency, wherein said control circuit of said laser is adapted to compare the intermediate frequency with the local reference frequency, and to control said collimator to increase a phase when the output frequency is higher than the local reference frequency and to decrease the phase when the output frequency is lower than the local reference frequency;
• and
• using the optical data transmission device for data communication in an optical data network.