Laser device with wavelength stabilization control and method of

Abstract

Methods of controlling the wavelength and output power of a laser device with two intracavity etalons are disclosed, together with a wavelength monitor capable of detecting sidebands. A method is characterized by the usage of hot/cold parameter K which takes two values 0 and 1 indicating the cold and hot state of the device, respectively. The parameter K, which is reset to 0 at the start, is set to 1 when the laser beam is stabilized; it is reset to 0, whenever the lasing pause exceeds a predetermined time length. Preparatory starting steps are performed or omitted at the start, depending on the value of K. Another method is characterized by the adjustment of the intracavity etalons during the lasing pauses, in accordance with exponential functions with thermal time constants. The sideband detecting wavelength monitor comprises a single etalon whose free spectal region FSRm is selected with respect to that, FSR.sub.2, of the fine tuning intracavity etalon in such a manner that the interference fringes of the sidebands formed by the monitor etalon are distinct from each other and from those of the central wavelength .lambda..sub.0. Namely, when i is the integer which is associated with a sideband wavelength .lambda..sub.S via the equation: .lambda..sub.S =.lambda..sub.0 +i.times.FSR.sub.2, the free spectral regions FSR.sub.2 and FSRm are selected in such a manner that the apparent wavelength differences: R=i.multidot.FSR.sub.2 +j.multidot.FSRm between the central wavelength .lambda..sub.0 and the sideband wavelengths .lambda..sub.S, wherein j is an integer which minimizes the value of R for each i, are different from zero and from each other.