Hughes Aircraft Company

Michael T Braski

Richard A Tilton

Paul F Robusto

Charles H Wissman

John C Hamacher

Dwight H Everett

J Samuel Mueller

Frequency stabilization in an RF excited carbon dioxide waveguide laser (10, 110, 210, 310) is obtained by employing as an imput to a dither stabilization feedback circuit (24, 124, 224, 324) an RF return power signal (62) that is a reflection of the exciting RF signal caused by mismatch of RF power source (14, 114, 214, 314) impedance and impedance of the laser cavity. The laser is operated so as to keep the RF return power from having its minimum magnitude. By employing an RF return power signal that is never at its minimum value, the system is insensitive to a wide range of thermal variation, and need for an optical laser output power sensor is eliminated.

Laser frequency stabilization

A laser transmitter utilizes optical far field combination of two independent lasers (80,90) and variation of RF exciting power (86) to one (80) to produce sufficient frequency modulation. Two bores (122,124) within the same dielectric body (120) are provided with two independent sets of electrodes (134,135, 138,139) and two independent RF power sources (150,152). The lasers are operated at different frequencies and the beams transmitted in parallel adjacent paths to provide a combined far field optical beam component at the beat frequency of the two lasers. Variation of the frequency of one of the lasers provides frequency modulation of the far field beat frequency, enabling reception and demodulation of the modulated beam without use of a local oscillator laser at the receiver. The transmitter may also be used in a laser radar.

FM laser transmitter

A laser array having effectively separate oscillation regions 70,72,74 that are locked in phase is formed with a ceramic body 60,64 having a single, unpartitioned and relatively wide cavity area 62. Effectively isolated separate side by side laser oscillation regions 70,72,74 within the cavity are provided by use of common reflector optics 66,68 on the respective ends of the common cavity, 62 with one of the end optic arrangements comprising a common substrate 100 provided with several separate areas 102,104,106 of high reflectivity, mutually spaced from one another by areas of relatively low reflectivity. Individual control of the several separate regions of laser energy oscillations is provided by employing a separate pair of exciting electrodes 76,78,82,84,88,90 for each such region and applying separate RF exciting signals to the separate pairs respectively. In a large array, whether using plural isolated regions of laser oscillations in a common cavity or plural bores 121,122,123,124,125 separated by intra-cavity partiitons 126,127,128,129, adjustment of exciting power 150,154 to the outer electrode pairs 134,135,142,143 provides frequency correction for distortion and phase de-locking due to transverse thermal gradients.

Phase locked laser array

A radio frequency excited carbon dioxide laser (50) is stabilized by sensing (66) variation in output power to generate a feedback signal (68,78 ) that is employed to vary amplitude of the radio frequency exciting signal from a power source (62). Frequency modulation of the laser output is achieved by varying the amplitude of the radio frequency signal from a power source (62) in response to a frequency modulating control signal from a modulation source (74). Both stabilization and frequency modulation are accomplished by combining the sensed power feedback signal with the frequency modulation control signal in a summing circuit (70) and employing the combined signal to vary magnitude of the radio frequency exciting signal.

Laser frequency control

An RF laser structure (10) is disclosed which includes an elongated laser excitation cavity (27) and an electrode structure (20) for suppressing extraneous RF discharges outside of the laser cavity. The electrode structure includes an electrode (41) adjacent the elongated laser cavity (27) and extending along the laser cavity; a conductive structure (43, 45) adjacent and conductively coupled to the electrodes (41) for shielding the electrode and for providing smooth conductive surfaces; and a dielectric filler (47) encapsulating the electrode and the conductive structure, and for controlling the electric field generated by the electrode structure so that extraneous discharges are suppressed. Also disclosed is a method for making a laser electrode structure which includes the steps of forming an electrode adjacent the elongated laser cavity, and encapsulating the electrodes with a dielectric potting material.

Method of making a laser electrode structure

An RF laser structure (10) is disclosed which includes an elongated laser excitation cavity (27) and an electrode structure (20) for suppressing extraneous RF discharges outside of the laser cavity. The electrode structure includes an electrode (41) adjacent the elongated laser cavity (27) and extending along the laser cavity; a conductive structure (43, 45) adjacent and conductively coupled to the electrode (41) for shielding the electrode and for providing smooth conductive surfaces; and a dielectric filler (47) encapsulating the electrode and the conductive structure, and for controlling the electric field generated by the electrode structure so that extraneous discharges are suppressed. Also disclosed is a method for making a laser electrode structure which includes the steps of forming an electrode adjacent the elongated laser cavity, and encapsulating the electrode with a dielectric potting material.

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Carlsbad, CA, United States of America

Michael T Braski