Abstract: An etalon stabilized external cavity laser. The present invention is embodied in an external cavity laser and utilizes a servo circuit to adjust the angle of an intra-cavity etalon to suppress multimode operation of the laser. The servo circuit employs a diode detector to detect a beat frequency that occurs during multimode laser operation. The output from the diode is amplified, compared and integrated to produce a control signal. This signal is used to control the angle of the etalon and thereby suppress the multimode operation of the laser.