Abstract: A semiconductor laser device including a mounting body having a step including an upper level, a lower level and an inclined plane provided between the upper and lower levels; and a semiconductor laser element mounted on the lower level, the mounting body further having a pin-type photodiode including a region of a first conduction type, and i-type region and a region of a second conduction type, a portion of laser beam emitted from the laser element being reflected by the inclined plan and output therefrom, a reminder of the laser beam emitted from the laser element being incident into the mounting body through the inclined plane and detected by the photodiode, the i-type region of the photodiode being provided on the inclined plane so that a major part of the remainder of the laser beam can enter the i-type region without passing the region of a first conduction type and the region of a second conduction type of the photodiode.

Abstract: External cavity semiconductor lasers using a saturable Bragg reflector as an external reflector are mode locked and produce output pulses of 1.9 ps from a semiconductor lasers without dispersion compensation. By coupling the output to a standard single mode fiber with a length of 35 m to compensate the linear chirp, the mode-locked pulse duration as short as 880 fs is achieved.

Abstract: A non Q-switched erbium laser operating on the I11/2→I13/2 transition produces laser output pulses characterized by a single spike containing approximately 90% of the energy, rather than a series of multiple spikes. The laser includes an optical gain medium with erbium being the lasing species, such as an erbium doped YAG rod. The gain medium is pumped with a flashlamp, with the voltage applied to the flashlamp and the duration of the applied voltage being carefully controlled to produce the single spike laser output. Depending upon the operating conditions, the full width half maximum (FWHM) of the spikes can be varied between 0.1 and 10 microseconds. The output of the erbium has fewer than 10 transverse modes. Output from the erbium laser may be directed onto corneal tissue in a preferred corneal sculpting procedure, in which the ablation rate is limited to no more than about 3 microns per laser pulse.

Abstract: A buried heterostructure (BH) laser source with a narrow active region is disclosed for use in close proximity with optically-addressed data storage media for read/write functionality in a relatively high data density format. The BH laser source is formed on a pregrooved or prepatterned substrate to form mesas upon which epitaxial layers are formed to form laser source active regions that have small emission apertures at the laser source facet output. Selective removal of semiconductor cladding material and replacement of this material with lower refractive index materials provides a way of obtaining further mode size-reduction at the output facet of the laser source. Each mesa has a top surface and adjacent sidewalls such that in the growth of the epitaxial layers above the active region doped with a first conductivity type, the above active region epitaxial layers depositing on the top surface deposit as a first conductivity type and depositing on said sidewalls deposit as a second conductivity type.

Abstract: A gas laser oscillator having at least three discharge tubes disposed along the optical axis, and a spacer having an opening centered on the optical axis. The spacer is disposed between a partially reflective mirror and the closest discharge tube. Further, the discharge tubes are disposed in series along the optical axis, and satisfy the following three formulas simultaneously: Formula 1 r1/r2 > 1.0 Formula 2 L2/(L1 + L2) < 0.85 Formula 3 r3/r2 < 1.4 where the sum of lengths of a pair of discharge tubes disposed at both ends in optical axis direction is L1, the inside diameter of these discharge tubes is r1, the sum of lengths of the other discharge tubes in the optical axis direction is L2, the inside diameter of these discharge tubes is r2, and the inside diameter of the opening of the spacer is r3.