Abstract: A method for generating ultra-short pulse amplified Raman laser light. Short pulse laser light is amplified, and a portion thereof is introduced into a Raman oscillator to produce compressed laser light. The compressed light is introduced to a first Raman amplifier. The remainder of the short pulse laser light is introduced to a polarizer, and the reflected light is introduced into the first Raman amplifier to pump it. The light transmitted through the first Raman amplifier that has not contributed to pumping is introduced to a beam splitter to produce a second reflected light that is passed to a second Raman amplifier to pump that amplifier. The compressed light is amplified in the first Raman amplifier and introduced to the second Raman amplifier to further amplify it. This further amplified radiation is passed through delay lines to the beam splitter, which passes only first Stokes radiation to generate ultra-short pulse amplified Raman laser light.

Abstract: A method of fabricating an indium phosphide-based vertical cavity surface emitting laser (VCSEL) having a high reflectivity distributed Bragg reflector (DBR) that is particularly adapted for emitting a light having a center wavelength of around 1.30 micrometers. The method includes the steps of selecting a specific operating wavelength, determining the photon energy corresponding to the selected operating wavelength, selecting a maximum operating temperature in degrees Centigrade, and fabricating at least half of the high index layers of the distributed Bragg reflector (DBR) of the VCSEL from AlGaInAs or other material that can be epitaxially grown on the InP substrate to have a band gap equal to or greater than the sum of the photon energy (in milli-electron volts) plus the sum of the maximum operating temperature plus 110 divided by 1.96.

Abstract: A laser and method for operating a laser and disclosed. The laser may include a first discharge electrode and a second discharge electrode positioned at a distance from the first electrode. A laserable gas may be provided together with a circulation system to flow the gas into a space between the electrodes. A voltage source may be connected to the electrodes for creating a discharge in the space; and a flow guide having a guide surface in contact with the gas may be provided that is guide selectively moveable relative to the first electrode to guide a flow of gas into the space. In one implementation, the flow guide directs flow toward an extremity of the first electrode and is adjustable to direct flow toward the extremity as the first electrode wears.

Abstract: A laser driver circuit for burst mode transmission is equipped in a transmitter at a client side within a P2MP (Point to Multipoint) optical network. The laser driver circuit utilizes a laser driver chip for a continuous mode. The selected laser driver chip is capable of working under an open-loop situation. A burst signal containing time slot information is fed to the switch connected to the laser driver chip. If the burst signal is enabled, a resistor of a predetermined value is connected to the laser driver chip via the switch so that normal driving current is generated for data transmission. If the burst signal is disabled, another resistor whose value is greater than the predetermined value is connected to the laser driver chip via the switch so that no or almost no driving current is generated, thereby avoid the signal collision problem of the channel shared by multiple clients.

Abstract: First and second diffraction grating layers are provided above a semiconductor substrate, and are spaced from each other in an output direction of a beam with a flat connecting layer sandwiched therebetween. An active layer is disposed above or below the first and second diffraction grating layers and the connecting layer. A cladding layer is disposed above the active layer or above the first and second diffraction grating layers and the connecting layer. A diffraction grating including the first and second diffraction grating layers has a plurality of slits penetrating from an upper surface to a lower surface that are perpendicular to the output direction of the beam. The connecting layer is formed from two layers grown epitaxially in a direction perpendicular to the output direction of the beam. One of the two layers is formed of the same material as the first and second diffraction grating layers.

Abstract: An electrooptic device (1) such as a distributed feed back semiconductor laser or a semiconductor modulator comprises an optical waveguide. A contact layer (11) is applied to the optical waveguide for conducting electrical current to the device for driving or modulating it. The contact layer is connected to the end of an electrically conducting path (3) and can have a shape, as seen perpendicularly to the surface of the device, to give an electric resistance between the end of the path and different areas at the optical waveguide which resistance is higher for areas located close to the ends of the device than for areas are located at the central region of the device. The shape can be si-milar to a trapezium having concave oblique sides and is selected so that the resulting varying electrical resistance gives a sub-stantially uniform electrical power or gain inside the optical waveguide, taken in the longitudinal direction of the waveguide.

Abstract: A simply structured apparatus according to the present invention corrects an overdrive power level. A main controller allows an overdrive power generator to set an overdrive power current to zero, allows a base power controller to control a base power current with the target value of a base power monitor level set to a desired overdrive power level. When the base power monitor level has reached the target value, the main controller allows said overdrive power generator to increase the overdrive power current until a base power control signal monitored by a base power control signal monitor reaches a value corresponding to a desired base power level.

Abstract: A wavelength locker comprising a semiconductor or air gap etalon is used to monitor and maintain the output wavelength of a coherent radiation source. Said etalon may be fabricated from a commercially available silicon wafer, with individual regions of the wafer, each functioning as a separate etalon, etched or otherwise processed to produce different thicknesses. Illumination by the coherent radiation source generated transmitted signal intensities that are detected and processed to determine the output wavelength of the coherent radiation source. A wavelength tuner is then used to maintain or vary the output wavelength based on continuous measurements of etalon signal intensity.

Abstract: A VCSEL having an N-type Bragg mirror with alternating layers of high bandgap (low index) and low bandgap (high index) layers of AlGaAs. The layers may be separated by a step change of Al composition followed by a graded region, and vice versa for the next layer, in the N-type mirror to result in a lower and more linear series resistance. Also, an N-type spacer layer may be adjacent to an active region of quantum wells. There may be a similar step in a change of Al composition from the nearest layer of the N-type mirror to the N-type spacer formed from a lower bandgap direct AlGaAs layer to provide lower free carrier absorption. With electron affinity engineering, a minority carrier hole barrier may be inserted adjacent to the quantum wells to improve hole confinement at high current density and high temperature.

Abstract: A semiconductor laser element comprising: a clad layer of a first conductivity type; an active layer; a first clad layer of a second conductivity type; a ridge made of a second clad layer of the second conductivity type and a cap layer of the second conductivity type, which are layered on the first clad layer of the second conductivity type, in this order starting from the first clad layer side; a dielectric film formed on ridge sides other than a top portion of the ridge; and a metal electrode layer that covers the ridge, wherein the width of the bottom of the cap layer and the width of the top surface of the second clad layer are approximately equal.

Abstract: A semiconductor laser device includes an n type diffraction grating layer of n-InGaAsP on an n-InP substrate, and having through-holes periodically disposed alongside of one another in a laser optical waveguide direction, an n-InP layer containing S as a dopant impurity in a concentration of at least 1×1019 cm?3. The through holes are buried in the n-InP layer, and an active layer is disposed on both the n-InP layer and the diffraction grating layer through an n-InP cladding layer.

Abstract: A vertical cavity surface emitting laser (VCSEL) in which a higher order lasing mode produces a Gaussian-like single mode far field beam intensity pattern. Such a VCSEL includes a protective surface deposition on a VCSEL structure, and phase filter elements on the surface deposition. The surface deposition and the phase filter elements implement an optical phase filter that induces optical path difference such that a single mode far field beam intensity pattern results when the VCSEL operates in a higher order lasing mode. The VCSEL can include structures that enhance a selected higher-order operating mode and/or that suppress unwanted operating modes.

Abstract: The present invention creates oxide and air apertures in material systems, such as InP, that do not usually accommodate epitaxial incorporation of highly oxidizing materials, such as AlAs, of sufficient thickness to adequately provide optical as well as current aperturing. A composite structure of relatively slowly oxidizing layer or layers (e.g. AlInAs on InP) with a faster-oxidizing layer or layers (e.g. AlAs on InP) can be used to produce oxide and air apertures of various shapes and sizes, and to also increase the oxidation rate.

Abstract: A quartz etalon having light reflecting film layers on the Z-cut surfaces and electrode layers on the X-cut surfaces are axially supported in the X-cut surface electrode layers. A dither signal is applied to this axially supported portion to resonate the etalon. In this state, laser-beam is transmitted through the Z-cut surfaces of the etalon. The transmitted light is photo-electrically converted and subjected to synchronous detection by a dither signal. On the basis of an error signal obtained by the detection output, the oscillation wavelength of the semiconductor laser is controlled. Since the etalon resonates as its axially supported central portion functions as a node, the mechanical loss is small, and the Q value upon mechanical resonance is extremely large. This makes the synchronous detection output about 100 times as large as the conventional value. This increases the signal-to-noise ratio of the photoelectric conversion signal, and increases the wavelength accuracy.

Abstract: A design of a vertical cavity surface emitting laser chip suitable for high speed data communication. An intracavity contact to the doped layers of the bottom mirror is formed so that both contacts are on the top epitaxial side of the wafer. These main structural features can be used to reduce the bond pad capacitance by a suitable spatial separation of metallizations of the p and n contact. The bond pads are processed as a short symmetric coplanar line in a ground signal ground configuration which allows flexible device testing and packaging. A significant capacitance between the pads of the center strip and the outer ground strips is avoided by etching the doped semiconductor layers between these strips down to the semi-insulating substrate. This design avoids pad metallizations and the corresponding critical photolithographic steps over large height differences from the vertical cavity surface emitting laser mesa top to the substrate.

Abstract: A semiconductor laser with a semiconductor substrate, a laser layer arranged on the semiconductor substrate, a waveguide arranged parallel to the laser layer and a strip shaped grating structure is disclosed. The laser layer, the waveguide and the grating are arranged a configuration which results in weak coupling between the laser light and the grating structure, so that the laser light interacts with an increased number of grating elements. A process for the production of such a semiconductor laser is also disclosed.

Abstract: Apparatus and methods for compensation of asymmetric mode pulling in external cavity lasers and the like. An apparatus includes a wavelength locker or etalon device to provide an asymmetric power transfer function and generate a transmission peak or peaks of asymmetric shape. The asymmetry of the transmission peak may be in the form of a steeper slope on the long wavelength side of the peak than on the short wavelength side. The asymmetry of the transmission peak or peaks may be structured to compensate or correct for asymmetric mode pulling effects that arise in laser gain media during single mode laser operation.

Abstract: A method for fabricating a nitride semiconductor laser device including a step to expose surfaces of an n-type nitride semiconductor layer (102) and a p-type nitride semiconductor layer (108); a step to cover the surface of the multi-layered semiconductor; with an insulating film (109) that has a thickness greater than the difference in levels between the exposed surface of the n-type nitride semiconductor layer (102) and the outermost surface of the p-type nitride semiconductor layer (108); a step to flatten the surface of the insulating film (109); and a step to form an n-type electrode (111) and a p-type electrode (110) electrically connected to the n-type nitride semiconductor layer (102) and the p-type nitride semiconductor layer (108), respectively. This method makes it possible to obtain a nitride semiconductor laser device that is highly reliable and exhibits an excellent heat diffusing property.

Abstract: A surface emitting semiconductor laser includes a substrate, a laser portion having a first post construction that is provided on the substrate and has a contact region on a top surface thereof, and an electrode portion having a second post construction provided on the substrate. The electrode portion includes a conductive layer electrically connected to the contact region and extends therefrom.

Abstract: A gas discharge laser having an elongated cathode and an elongated anode with a porous insulating layer covering the anode discharge surface. A pulse power system provides electrical pulses at rates of at least 1 KHz. A blower circulates laser gas between the electrodes at speeds of at least 5 m/s and a heat exchanger is provided to remove heat produced by the blower and the discharges. In preferred embodiments at least a portion of the anode is comprised of lead, and fluorine ion sputtering of the anode surface creates the insulating layer (over the discharge surface of the anode) comprised in large part of lead fluoride. In a particular preferred embodiment the anode is fabricated in two parts, a first part having the general shape of a prior art anode with a trench shaped cavity at the top and a second part comprised of lead rich brass and disposed in the trench shape cavity.