Abstract: The invention relates to an active laser material having a base material doped with active ions, giving said base material laser properties, the ion concentration being equal to or higher than 2%.The invention also relates to a microlaser produced with such a material, as well as a process for producing such a material. The microlaser incorporates an active medium (6) produced by epitaxial growth on a substrate (8), the latter then being removable, as well as microlaser cavity mirrors (2, 4). A pumping beam (10) makes it possible to optically pump the cavity.

Abstract: A method and circuit is provided for more efficiently coupling light between two optical waveguides such as optical fibres. When the two waveguides are coupled to spaced apart collimating lenses such as GRIN lenses, the beam propagating between the spaced part lenses may be shifted. In this instance light can more efficiently be coupled out of the output optical fibre if it is angled with respect to the optical axis of the GRIN lens to which it is coupled. This invention provides an output fibre that is non-parallel with the optical axis of the lens it is coupled thereto.

Abstract: An apparatus and method for providing accurate sub-nanosecond timing control between the voltage outputs of branches of an excitation circuit which are driven by a common switch. This invention allows for the introduction of variable timing delays between the branches of the circuit, and eliminates relative timing jitter. Using saturable inductors with variable bias in the high-voltage excitation circuit, this invention provides a continuously tuneable delay on the subnanosecond time scale between two or more excitation circuit branches.

Abstract: A high-linearity light source comprising a first semiconductor diode (e.g., a light-source diode such as a laser diode or a light-emitting diode, or a light-receiving diode such as a photodetector) and a nonlinearity compensation network with a second, compensation, semiconductor diode is provided. The first and second diodes are connected in an antiparallel configuration with either an A.C. signal source (for light emission) or a load (for light receiving) and in separated D.C. bias paths.By varying the relative biasing of the diodes (e.g., using a variable resistor in series with a diode), the capacitance of the combination of diodes cancels, and the linearity of the system improves. With a properly biased compensation diode the even-order nonlinearity distortion can be cancelled completely.

Abstract: A method of controlling the size of a laser beam comprises the steps of generating the laser beam with a laser, focusing the laser beam, directing the laser beam to a target, directing a portion of the laser beam to an optical detector which generates a signal representative of a fluence distribution of the laser beam, and adjusting a focal point of the laser beam based on the measured fluence distribution to control the size of the laser beam on the target.

Abstract: A diode pumped laser wherein third harmonic generation at 355 nm is obtained from an intra-cavity-tripled diode-pumped Nd:YVO4 crystal utilizing an angle-tuned LBO doubler and tripler, and operated at high repetition rates and good overall efficiency. An average UV power of over 2 watts at 30 kHz and 1 watt at 100 kHz is typically obtained with a 20 watt diode array "bar" side-pumping a one percent (1%) Nd:YVO4 (vanadate) slab. The device utilizes room temperature intra-cavity doubling and takes advantage of a small beam waist at the doubler and tripler required with low-power CW diode pumping.

Abstract: A tool is used for end-to-end jointing a fiber to another fiber or to an optical connector end-piece by means of a module including a receiving housing enabling a fiber to be inserted at one end at least and wedging action arrangements for fixing the fibers at the bottom of the housing that are operated by pressing them in. The tool carries out the following operations successively and possibly simultaneously for two fibers: partial stripping of each fiber, end cleavage for end-to-end jointing, positioning of each cleaved fiber in the module where it is jointed and crimping of each fiber in a jointing position in the module. These operations are carried out in a cycle commanded by continuous rotation in a particular direction of a rotary drive shaft of the tool after manual fitting of each fiber and the module at particular positions on the tool.

Abstract: A laser diode package (1) couples laser diode outputs into a plurality of fibers (21), and these are bundled and brought to an output face (2') that produces a divergent composite beam from the fiber ends (21'). The beam end pumps a solid state laser (100) across a gap (6), and the divergence allows a wide tolerance in alignment of the pump and crystal (3). Preferably, one cavity mirror (7) is a focusing mirror that reconcentrates residual pump light in the desired mode. In a preferred embodiment, the output face of the package is at a short stub (2) or ferrule that provides a simple and effective pump beam centering alignment. The solid state laser (100) may be a rod or crystal (3) and is preferably sufficiently short, in relation to pump beam diameter and divergence in the rod, that the pump beam within the rod lies in the TEM.sub.OO mode volume of the laser cavity. A concave mirror then refocuses residual pump light back into that mode.

Abstract: A wavelength division multiplexer/demultiplexer is provided that integrates axial gradient refractive index elements with a diffraction grating to provide efficient coupling from a plurality of input optical sources (each delivering a single wavelength to the device) which are multiplexed to a single polychromatic beam for output to a single output optical source.

Abstract: A diode pumped, multi axial mode, intracavity doubled, intracavity tripled laser, includes at least two resonator mirrors defining a resonator cavity. A laser crystal and a doubling crystal are positioned in the resonator cavity. A tripling crystal is also positioned in the resonator cavity. A diode pump source supplies a pump beam to the laser crystal and produces a laser crystal beam with a plurality of axial modes that are incident on the doubling crystal. This produces a frequency doubled output beam.Further, a diode pumped, multi axial mode, intracavity nonlinearly-converted laser is provided and includes at least two resonator mirrors defining a resonator cavity, a laser crystal and a nonlinear conversion apparatus positioned in the resonator cavity. A nonlinear conversion apparatus is also positioned in the resonator cavity.

Abstract: A semiconductor light source system includes a laser diode that is operated in a variable temperature environment and a driver circuit, wherein the driver circuit sets a magnitude of a signal current supplied to the laser diode below an upper limit level that corresponds to a maximum operational temperature of the laser diode. The driver circuit simultaneously sets a relative magnitude of the signal current with respect to a bias current such that a sufficient extinction ratio is achieved in an output optical beam and further sets a relative magnitude of the signal current with respect to the bias current such that a sufficiently small oscillation delay is achieved in the laser diode.

Abstract: An optical AND gate includes at least one semiconductor laser amplifier (SLA) and inputs for first and second optical signals. The gate produces an output corresponding to the AND product of A and B. In one aspect of the invention, the first and second signals are equal in wavelength. The gate may comprise a single SLA which receives the first signal A together with a third signal P, which may be a continuous wave pump. The second signal B is input in an orthogonal polarization state to A and P. Alternatively, the gate may comprise a pair of SLAs. A first SLA receives the first signal A together with the pump P. A sideband is selected from the output of the first SLA and input to the second SLA together with the second signal B. A sideband is selected from the output of the second SLA corresponding to the AND product C of A and P with B.

Abstract: An optical structure which is suitable as an optical waveguide or cavity comprises a carrier having a lattice structure with a photonic band gap and a defect region. The lattice structure comprises pores which have constriction and are arranged in a periodic grid pattern which is disturbed in the defect region. The optical structure can be produced by the electrochemical etching of silicon.

Abstract: A pair of elongated, parallel electrodes (91,92) are insulatively mounted within a tubular housing (111) filled with a laser gas mixture between an arrangement of reflective optical elements (120,150) sealingly mounted at each end of the housing. The electrodes form a rectangular gas discharge area (40) the minimum spacing (a) between which is the diameter of the fundamental free-space mode of the stable, laser resonator (17) formed in the gap when the electrodes are rf excited (13). A multi-pass optical configuration (30,50) uses the full width (b) of the active medium to produce a high power, compact laser (10,200). Deformable support rings (97) are compressed to push the electrodes apart against small cylindrical spacers (99) abutting the inner walls of the housing to maintain the electrodes' spatial relationship. The rf feeds (103) sealingly (112) connected to the electrodes through the housing without disturbing the uniform distribution of forces on the electrodes.

Abstract: An optical system such as an add and/or drop WDM multiplexer allows the wavelength fluctuation of an optical carrier to be tracked so that a corresponding fiber Bragg grating (FBG) can be responsively tuned. The preferred embodiment of the wavelength tracking system in an optical system such as an add and/or drop module includes a three-port optical circulator, three optical fibers, a series of tunable FBGs, a source of a broadband optical noise signal, an optical spectrum analyzer (OSA), and an FBG tuner. In operation, an LED generates modulated probe lightwaves that are inserted into a drop module. The LED lightwaves and the optical carriers propagating through the drop module are monitored by an OSA. The monitoring procedure determines the conditions, in terms of target wavelengths of the FBGs, and the stability or instability of the optical carriers. The FBGs are then tuned in response to the FBG and optical carrier information.

Abstract: A laser light generating apparatus in which the laser light from a laser light source is intensified by an optical resonator arranged outside the laser light source and outputted after wavelength conversion by a non-linear optical crystal element arranged within the optical resonator. The laser light generating apparatus includes a laser light source for radiating the laser light, an optical resonator for resonating the laser light radiated from the laser light source, a non-linear optical crystal element having an anti-reflection film formed on its laser light incident surface and an aperture for interrupting the light reflected by the non-linear optical crystal element within the optical resonator. The non-linear optical crystal element is arranged in the optical resonator so that a line drawn normal to the laser light incident surface will be obliquely inclined relative to the optical axis of the laser optical resonated within the optical resonator.

Abstract: A temperature compensated laser diode transmitter circuit includes a laser diode, a driver circuit for supplying an a.c. drive current to the laser diode, a thermistor arranged to thermally sense the laser diode, a current source having a first and a second current output controlled by the thermistor, the first current output connected to the driver for temperature compensating the drive current, and the second current output connected to supply a temperature compensated bias current to the laser diode.

Abstract: The instant invention relates to a laser system for optical free space communications, in particular the generation of amplified laser light under conditions in outer space. In the process, an optical beam (72) to be amplified is conducted via a polarizing beam splitter (71) to a Faraday rotator (70) and brought from there to a neodymium crystal (68). By means of reflection, appropriate diffraction and passage through a quarter-wave plate (67), a multiple passage through the neodymium crystal (68) is forced and amplification is achieved by this.

Abstract: A grating-in-etalon wavelength division multiplexing device is disclosed. In one aspect the device includes an etalon structure with a single volume (or Bragg) diffraction grating, multiple superimposed volume diffraction gratings or a binary volume supergrating is interposed between the reflective opposed faces of the etalon. The etalon includes a tilt mechanism for tilting one or both of the reflective faces at a preselected angle with respect to each other from the parallel. A multiple wavelength light beam is directed through the volume grating in different preselected directions so that light of wavelengths satisfying the Bragg condition on each traversal of the grating is diffracted in a direction different from the direction of the incident beam. The diffracted beam exits the etalon and is wavelength interrogated in a detector while the undiffracted wavelengths propagate through the grating to be reflected from the opposed mirror face back through the volume grating.

Abstract: The present invention relates to a semiconductor laser drive device, and an image recording device whose function includes scanning a predetermined body to be scanned with a laser beam carrying image information in the course of recording an image, and which makes high speed image regeneration while maintaining a high quality of the image, wherein the devices are equipped with a first feedback circuit including a first operational amplifier and a second feedback circuit including a second operational amplifier, so that the double feedback can concurrently be effected to obtain current vs. light output characteristics with a high speed and high accuracy in an analog mode.