Abstract: In a laser module comprising a hermetically sealed container having inside a semiconductor laser device whose emission wavelength is 350˜450 nm, generation of organic volatile gas is suppressed in the container and life of the module is prolonged. In a laser module comprising a hermetically sealed container having inside a semiconductor laser device whose emission wavelength is 350˜450 nm, optical components whose organic volatile gas generation measured by GC/MS is 10 ?g/g or less at 150° C. are positioned in the container. In addition, as an organic adhesive to fix the optical components such as a collimating lens is used an organic adhesive whose organic volatile gas generation measured by GC/MS is 100 ?g/g or less at 150° C.

Abstract: An optical semiconductor device includes a wavelength-tunable semiconductor laser chip, a mount carrier, a first temperature sensor and a wire. The wavelength-tunable semiconductor laser chip has a first optical waveguide and a second optical waveguide. The second optical waveguide has a heater on a surface thereof and is optically coupled to the first optical waveguide. The mount carrier is for mounting the wavelength-tunable semiconductor laser chip, and has a first area arranged at a surface of the mount carrier of the first optical waveguide side when the wavelength-tunable semiconductor laser chip is mounted. The first temperature sensor is mounted on the first area. The wire couples between the heater and a second area arranged at a surface of the mount carrier of the second optical waveguide side when the wavelength-tunable semiconductor laser chip is mounted.

Abstract: It is an object to provide a laser apparatus, a laser irradiating method and a manufacturing method of a semiconductor device that make laser energy more stable. To attain the object, a part of laser beam emitted from an oscillator is sampled to generate an electric signal that contains as data energy fluctuation of a laser beam. The electric signal is subjected to signal processing to calculate the frequency, amplitude, and phase of the energy fluctuation of the laser beam.

Abstract: In a display device that displays a video by scanning coherent light across a screen, modulation at high speeds and gradation are necessary for a coherent light source. An oscillation wavelength of a semiconductor laser outputting the fundamental wave is changed at high speeds through the plasma effect induced by applying a pulse current to the coherent light source. A change of the wavelength causes the output of a higher harmonic generated in a light wavelength conversion element to change, and gradation is produced using such a change.

Abstract: The invention relates to a method for regulating the average wavelength of a laser, especially a semiconductor laser, comprising a wavelength-selective, at least partially reflecting optical element (27) and being operated in a unimodal manner.

Abstract: The present invention provides an apparatus for monitoring a laser. The apparatus includes a plurality of sensors and a monitoring device capable of communicating with the plurality of sensors and configured to monitor an operating status of a laser. The plurality of sensors includes an optical power sensor, a first temperature sensor, and a power sensor and/or a current supply sensor. The present invention also provides a method for monitoring a laser. The method includes measuring an output optical power of the laser, measuring a temperature of the laser and/or a lasing medium exciting device, measuring an amount of current supplied to the exciting device and/or an amount of laser cavity excitation, and determining a current and/or predicted health status of the laser based on at least one of the optical power, the temperature of the laser, the temperature of the exciting device, the current and the driver power.

Abstract: Output power of light emitted from a data transmission light source is determined based upon forward voltage, forward current, ambient temperature and a factor specific to the manner in which the light source is mounted. Output power is determined with sufficient accuracy to control operation of the data transmission light source for compliance with eye safety and transmission protocol requirements without use of a complex lens and monitor diode.

Abstract: The present invention is a self-seeded laser diode. The laser diode obtains a gain by itself without using expansive erbium-doped fiber amplifiers. Hence, the cost is reduced and the system is simplified.

Abstract: In a laser module comprising a hermetically sealed container having inside a semiconductor laser device whose emission wavelength is 350˜450 nm, generation of organic volatile gas is suppressed in the container and life of the module is prolonged. In a laser module comprising a hermetically sealed container having inside a semiconductor laser device whose emission wavelength is 350˜450 nm and whose life is 5500 hours or more, optical components whose organic volatile gas generation measured by GC/MS is 10 ?g/g or less at 150° C. are positioned in the container. In addition, as an organic adhesive to fix the optical components such as a collimating lens is used an organic adhesive whose organic volatile gas generation measured by GC/MS is 300 ?g/g or less at 15° C.

Abstract: An improved method of subtracting laser amplitude fluctuations from a desired signal in a multi-line laser system and a detection system having improved noise cancellation are provided. This invention reduces the noise contribution from laser amplitude fluctuations by matching the spectral dependence of the light seen at a monitor of the laser output to the spectral dependence of a desired signal. This spectral matching results in an improved correction of the laser power in a desired signal.

Abstract: A temperature stabilizer for accurately stabilizing the temperature of an object is provided. The temperature stabilizer stabilizes the temperature of an object to a reference temperature. The temperature stabilizer includes an oscillator provided in proximity to the object, for generating an oscillation signal having a frequency corresponding to an inputted frequency control signal, a phase detector for detecting the phase difference between a feedback signal based on the oscillation signal and a reference clock signal having a predetermined frequency, a loop filter for generating the frequency control signal to synchronize the feedback signal with the reference clock signal based on the output from the phase detector, a comparator for comparing the value of the frequency control signal with a reference value determined corresponding to the reference temperature and an electric heating converter for heating or cooling the object based on the comparison result from the comparator.

Abstract: The object of the present invention is to provide an optical module for the WDM communication system, in which the oscillation wavelength is on the grid of the WDM regulation, moreover the optical output power and the oscillation wavelength can be controlled independently. The present module comprises a semiconductor light-emitting device, a wedge shaped etalon device and two light-receiving devices. The etalon device contains a first portion, on which the anti-reflection films are coated, and a second portion. One of the receiving devices detects light transmitted through the first portion of the etalon device, while the other device detects light through the second portion. Signal from the former device controls the output power of the light-emitting device, while the signal from the latter receiving device controls the oscillation wavelength of the laser.

Abstract: An optoelectronic device having a semiconductor laser diode and a grating structure for stabilizing the optical wavelength of optical radiation generated by the laser diode.

Abstract: A system for locking the operating wavelength of an optical transmission source, the system including: a pattern of nanostructures being optically coupled to the optical transmission source and adapted to perform notch filtering; at least one photodetector optically coupled to the pattern of nanostructures; and, at least one controller operatively coupled to the photodetector and optical transmission source to operate the optical transmission source responsively to the at least one photodetector.

Abstract: An erbium-doped (Er-doped) superfluorescent fiber source (SFS) has an enhanced mean wavelength stability. A method determines an estimated mean wavelength of a SFS. The method includes providing an Er-doped SFS having an actual mean wavelength. The method further includes configuring the SFS such that the actual mean wavelength has a dependence on the temperature of the EDF. The method further includes obtaining the dependence of the actual mean wavelength on the temperature of the EDF. The method further includes measuring the temperature of the EDF. The method further includes calculating the estimated mean wavelength using the measured temperature of the EDF and the dependence of the actual mean wavelength on the temperature of the EDF.

Abstract: Using a switching signal from a coarse/fine switching and operation mode switching circuit, the width of change of a counter control value during power up is increased, and the width of change is reduced once a steady state is reached. In the steady state, the frequency of updating is limited by a control signal from an update permit control circuit. In the steady state, the frequency band of a current source in an LD driving circuit is reduced in width.

Abstract: A laser controlling method can generate laser of stable laser pulses, and eliminate useless time from a machining procedure. The method uses a gain medium and a Q-switch, and emits exciting light to the gain medium, thereby setting the Q-switch in a continuous oscillation mode, and prepares a given Q-switch pause time before a laser pulse is generated. When the continuous oscillation is kept going longer than a given time, the control method sets a Q-switch pause time for obtaining a first laser pulse to be different from a Q-switch pause time for obtaining a second laser pulse and onward.

Abstract: In a laser light generating device, the stability against vibration and time-dependent changes will be improved, and influences of temperature changes exerted on the resonator will be reduced. In a laser light generating device (1) which includes an excitation light source (2) for generating a continuous-wave excitation light and a solid-state laser resonator (4) based on using thermal lens effect caused by heat generation at a position of excitation, the solid-state laser resonator further includes a laser medium (4a) a saturable absorber (4b) an intermediate medium (4c) and reflection means (4d) as the constituents. Influence of vibration is reduced by bonding a substrate of the laser medium (4a) and a substrate of the saturable absorber (4b) so as to integrate them.

Abstract: Apparatus and methods for altering one or more spectral, spatial, or temporal characteristics of a light-emitting device are disclosed. Generally, such apparatus may include a volume Bragg grating (VBG) element that receives input light generated by a light-emitting device, conditions one or more characteristics of the input light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light.

Abstract: Provided are a surface emitting laser device having an optical sensor, and an optical waveguide device employing the same. The surface emitting laser device having an optical sensor includes a surface emitting laser formed on a substrate and generating a laser beam to output it to outside, and an optical sensor formed adjacent to the surface emitting laser on the substrate and receiving external light. In the surface emitting laser device having the optical sensor, and the optical waveguide device employing the same, the surface emitting laser and the optical sensor are simultaneously integrated, however, the performance of the surface emitting laser is unaffected by the optical sensor and the optical sensor operates separately, exhibits high performance, and can respond within a wide wavelength band.

Abstract: Wavelength control and stabilization of a laser is achieved by a practical, inexpensive, and accurate technique adapted for most optical transmission system applications by a method involving a laser characterization phase and a laser wavelength control and stabilization phase. This technique is applicable to both single mode lasers and multimode lasers. It is especially useful in those applications where the desired laser output power can vary over a wide range, including relatively low power above the lasing threshold.

Abstract: A frequency-stabilized laser source that is adapted for use as a frequency standard. The frequency of the laser source is locked and the laser beam delivered by the laser source on a transition of an absorber chemical element. The technique combines both operation with saturated absorption and synchronous detection, based on modulating said transition being saturated by the beam passing through the absorber chemical element. This produces a single frequency laser beam whose output frequency is stationary. The frequency is not continuously modulated and is more precise than that which would be obtained operating with single-pass absorption only. The laser source is thus adapted for making a frequency standard.

Abstract: An exemplary optoelectronic transceiver 100 incorporating features of the present invention is shown in FIGS. 2 and 3. The transceiver 100 contains a receiver circuit, a transmitter circuit, a power supply voltage 19 and ground connections 20. The receiver circuit of the transceiver includes a Receiver Optical Subassembly (ROSA) 102, which may contain a mechanical fiber receptacle as well as a photodiode and pre-amplifier (preamp) circuit. The ROSA 102 is in turn connected to a post-amplifier (postamp) integrated circuit 106, the function of which is to generate a fixed output swing digital signal which is connected to outside circuitry via the RX+ and RX? pins 17. The postamp circuit 106 also often provides a digital output signal known as Signal Detect or Loss of Signal indicating the presence or absence of suitably strong optical input. The postamp circuit 106 does not necessarily have to be used to generate the Signal Detect or Loss of signal.

Abstract: A temperature insensitive diode-pumped solid state laser is disclosed in this invention. The components of the laser are optimized with temperature insensitive design, making the laser capable of operating in a wide temperature range without using any cooling/heating system to maintain the temperature of its components.

Abstract: A high power light source having an array, bundle or separate plurality of laser diodes coupled to a same number of multimode waveguides to collect beams of light emitted from the of laser diodes is provided. An optical combiner receives the beams of light and combines the beams of light into a single forward propagating beam of light so that substantially all optical radiation within each beam of light overlaps the optical radiation each other beam to form the single beam. A reflective element is located to receive the single forward propagating beam of light and transmits greater than 60% of the single forward propagating beam of light therethrough. The reflective element reflects between 3–40% of the single forward propagating beam back to the laser diodes as feedback to stabilize said laser diodes.

Abstract: A system for detecting wavelength error that includes one or more ordered pairs of photodetectors each of which receives an individual optical signal and is used to detect a wavelength error in that optical signal. Each individual optical signal is directed towards a corresponding pair of photodetectors. The pair of photodetectors are positioned around a region of maximum constructive interference or minimum insertion loss. A feedback circuit analyzes output signals from the photodetectors and determines wavelength error based on differences between the output signals from the photodetectors.

Abstract: A method and apparatus for temperature stabilization of a wavelength of a laser compensate for thermal instability of a internal etalon of the wavelength using the results of measuring the wavelength with an external wavelength meter.

Abstract: Disclosed is a method for maintaining wavelength-locking of a Fabry-Perot laser regardless of a change of external temperature even though a temperature controller is not used, and a wavelength division multiplexing (WDM) light source using the method, as an economical light source used in a WDM optical communication field. The WDM light source comprises a Fabry-Perot laser for injecting spectrum-spliced incoherent light to amplify and output only an oscillation mode matching with a wavelength of the injected light, and a bias controlling unit for adjusting a bias current supplied to the Fabry-Perot laser to a value adjacent to a threshold current of the Fabry-Perot laser, whose threshold current is changed according to a temperature and a relationship between the injected light changed depending to a temperature and a wavelength of the oscillation mode.

Abstract: The present invention relates to laser diodes with single mode emission at high output powers, as well as to structures and processes facilitating simple manufacture of such a devices. The invention includes a semiconductor laser (10) with a semiconductor substrate (11), a laser layer (13) arranged on the semiconductor substrate, an array of waveguide ridges (18) arranged at a distance from the laser layer, and several strip-shaped lattice structures (23) arranged on the flat surface between the waveguide ridges. The lattice structure (23) is formed on an insulating or barrier layer (26) at a distance from the laser layer above the laser layer (13). Processes for the production of such a semiconductor laser are also disclosed.

Abstract: Systems and methods for regulating optical power are described. A system for regulating optical power includes a laser driver circuit that receives an enable/disable signal and a data modulator input. The enable/disable signal regulates asynchronous mode operation. The system also includes a laser module including a laser diode emitter and a photodiode detector. The laser module is coupled to the laser driver circuit and receives a laser bias current from the laser driver circuit. The system also includes a switch coupled to the photodiode to receive a signal from the photodiode detector. The system also includes an automatic power control (APC) feedback circuit that receives a signal from the switch and provides a laser bias current feedback signal to the laser driver circuit to compensate for power output changes in the laser diode emitter over time.

Abstract: An optical module, such as a package for a vertical cavity surface emitting laser diode (VCSEL) or other light emitting device, includes monitoring of the emitted optical power by tapping the transmitted beam. The module includes a substrate, which carries the light emitting device and an optical monitor. In addition, the module includes a transparent plate with at least two reflective regions that together redirect part of the light from the light emitting device to the optical monitor.

Abstract: According to an aspect of the present invention, a nitride semiconductor laser device includes a nitride semiconductor active layer, and a stripe-shaped waveguide for guiding light generated in the active layer. At least one pair of light-absorbing films are provided in at least local regions on the opposite sides of the stripe-shaped waveguide, to reach a distance within 0.3 ?m from the waveguide. According to another aspect of the present invention, a gan-based semiconductor laser device includes first conductivity type semiconductor layers, a semiconductor active layer and second conductivity type semiconductor layers stacked sequentially. The laser device further includes a ridge stripe provided to cause a refractive index difference for confinement of light in a lateral direction crossing a longitudinal direction of a cavity, and a current-introducing window portion provided on the ridge stripe.

Abstract: A method and assembly for frequency stabilization of an optical signal especially from a laser, the assembly (11) comprising beam splitter (15), a passive frequency discriminator (16), and a pair of photodiodes (17 & 18). The beam splitter (15) in use receives a collimated optical beam (B) and diverts a sample beam (B1) which is directed towards the discriminator (16) which transmits a portion (B2) of said sample beam to one of the photodiodes (17) and reflects a second portion (B3) of said sample beam to the other photodiode (18). A control signal (S3) is derived from the respective intensities of the transmitted and reflected portions of the sample beam, and utilized to operate the electronic control to adjust the frequency of the laser output signal, if required, to maintain a specified frequency.

Abstract: The dependency of intensity noise is used to determine the wavelength difference between a laser diode gain peak and a reflection peak of a fiber grating in a fiber grating type laser diode. Monitoring and determining the relative noise intensity of such a laser enables the control of the laser diode or the fiber grating such that the intensity noise is as low as possible. Such an approach enables the use of a fiber grating type laser diode as Raman pumps in high-speed transmission systems where low intensity noise is a requirement, especially when the Raman pump power propagates in the same direction as the transmission signals (known as Raman co-pumps).

Abstract: The present invention provides for a method for configuring a laser operating system. More specifically, the system utilizes a graphical user interface (GUI) to allow an operator to interact with an embedded controller and set parameters for an optical communications transceiver. The system adjusts parameters such as laser bias and modulation currents, wavelength, qualification tests, and file management. In other words, the GUI manages configurations of a transceiver operating system. The system provides for an efficient method to design a laser transceiver and to perform and manage qualification tests. The embedded controller may contain a real time operating system that controls multiple functions in the transceiver and an optical channel. The GUI interacts with an operating system to download embedded firmware into an embedded micro controller unit (MCU). Downloading of firmware allows for multiple special programs from different sources to be integrated.

Abstract: There is provided a broadly tunable laser beam generator serving as a laser beam source which utilizes a nonlinear optical effect of a silica (glass) fiber and which is broadly tunable in the near-infrared region, having ultra-broad tunability which has not been easily achieved by known tunable lasers, and generating coherent light which can be continuously swept over the entire wavelength region with a simple mechanical operation of a single wavelength selecting element and which is emitted in a constant direction independent of its wavelength. The laser beam source which utilizes a nonlinear optical effect of a silica optical fiber (8) and which is broadly tunable in the near-infrared region has ultra-broad tunability and generates coherent light which can be continuously swept over the entire wavelength region with a single wavelength selecting element (10).

Abstract: A laser oscillation apparatus includes a wavelength change unit for driving a wavelength selection element in a band-narrowing module and changing the oscillation wavelength of a laser beam to a target value, and an oscillation history memory for storing the oscillation state of the laser beam as an oscillation history. The wavelength change unit drives the wavelength selection element on the basis of the oscillation history and changes the oscillation wavelength of the laser beam to the target value.

Abstract: A system and method of sensing temperature at an optical fiber tip, including the steps of positioning a slug of fluorescent material adjacent the optical fiber tip, providing an optical stimulus having a wavelength within a first predetermined range through at least one fiber optically linked to the optical fiber tip, wherein a desired optical fluorescent response having a wavelength within a second predetermined range from the fluorescent slug is generated, detecting a signal representative of the optical stimulus, detecting a signal representative of the optical fluorescent response, digitally processing the optical stimulus signal and the optical fluorescent response signal to determine a phase difference therebetween, and calculating a temperature for the optical fiber tip as a function of the phase difference.

Abstract: There is provided a phase control portion for controlling phase of a laser beam resonated in a resonator based on detected results by two optical detectors. The phase control portion adjusts the longitudinal mode positions by a feedback control so that a ratio of intensities detected by the two optical detectors comes to a predetermined reference value. To one of the optical detectors, part of a laser beam outputted from the resonator is irradiated as it is, whereas, to the other one of the optical detectors, part of the laser beam outputted from the resonator is irradiated after passing through an etalon. An FSR of the etalon is a double of that of another etalon in the resonator.

Abstract: A solid state zig-zag slab laser amplifier in which depolarization occurring at total internal reflection from opposed lateral faces of the amplifier slab is controlled by selecting a complex evanescent coating that provides a selected phase retardance that results in minimization of depolarization. Without use of the complex coating, small changes in incidence angles can result in phase retardance changes large enough to increase depolarization significantly, especially when the amplifier is operated at higher powers. Appropriate selection of the complex evanescent coating allows a desired phase retardance angle to be maintained relatively constant over a small range of angles of incidence, at a given wavelength, and therefore permits minimization of depolarization and birefringence effects.

Abstract: Apparatus and methods usable for wavelength references and measurement of wavelength of a light beam. The apparatus comprise at least two wavelength reference or filter elements positioned in a light beam, each wavelength reference element having a different free spectral range and operable to define a joint free spectral range, and a detector positioned in the beam after the wavelength reference elements. The joint free spectral range provided by the multiple wavelength reference elements results in a joint transmission peak that is centered at a unique wavelength, and maximum optical power detectable from the beam by the detector occurs at the center wavelength of the joint transmission peak.

Abstract: A solid laser apparatus has a wavelength converter temperature controller 40 arranged for driving a Peltier device 41 to control the temperature Tc of a wavelength converter 5 so that the acceptable wavelength range of the wavelength converter 5 adapts to the wavelength range of reflected light from the grating part 6 at the temperature Ti and a laser controller 60 arranged for driving a semiconductor light amplifier device 1 to maintain the intensity of the extraordinary component passed through the polarizer 52 and measured by a photometer device 57.

Abstract: The invention relates to the stabilization of high power semiconductor laser diode sources as they are extensively used in the field of optical communication. Such lasers are mostly employed as so-called pump laser sources for fiber amplifiers, e.g. erbium-doped fiber amplifiers, and are designed to provide a narrow-bandwidth optical radiation with a stable power output in a given frequency band. To improve the wavelength locking range of such laser sources when operating without an active temperature stabilizing element, an external reflector providing very high relative feedback is used. The reflectivity bandwidth of the external reflector is broadened for improving the stability of the laser source. In commonly employed optical fibers for conducting the laser beam, the external reflector is formed by one or a plurality of appropriately designed fiber Bragg gratings.

Abstract: An improved laser-based wafer carrier mapping sensor is provided. The sensor includes a number of improvements including laser source improvements; optical improvements; and detector improvements. Laser source improvements include the type of laser sources used as well as the specification of size and power of such sources. Optical improvements include features that intentionally defocus the laser stripe on the wafer as well as additional features that help ensure precision stripe generation. Detector improvements include increasing gain while decreasing the effects of ambient light. Various combinations of these features provide additional synergies that facilitate the construction of a sensor with significantly improved dynamic response while decreasing the frequency of false cross slot errors.

Abstract: According to each embodiment of the present invention, a phase-correlation can be generated between respective laser fields produced by a plurality of independent lasers. Specifically, based on a structure that first and second laser fields each having a mixed quantum state represented by a single-mode Glauber coherent state that a phase is completely indeterminate are mixed with each other and a quantum continuous measurement is performed by causing absorbers to individually cross two output quantum states, the phase-correlation can be generated between the first and second laser fields when absorption by the absorbers massively occurs in one of the two quantum states as a result of the quantum continuous measurement.

Abstract: A wavelength locker for use at more than one wavelength includes filters with different characteristics for a corresponding detector. The filters may be etalons having different free spectral ranges, e.g., having different apparent or real thicknesses. If more than three such filters are used outputting offset periodic signals, a reference detector may be eliminated and continuous operation over a wavelength range may be realized.

Abstract: A method and apparatus for stabilizing the output of a mode-locked laser by monitoring the temporal behavior of the pulse train profile and controlling the laser cavity optical length and/or loss modulation frequency accordingly. A mismatch of the cavity optical length and the loss modulation frequency will yield a first characteristic noise condition on the laser beam pulse train when the optical length is too short for a given loss modulation frequency and a second, different noise condition when the optical length is too long. The laser beam is monitored and analyzed to determine which noise condition is present. The cavity optical length is adjusted accordingly by movement of one or more optical elements or by changing the index of refraction of one or more optical elements. In the alternative, or additionally, the loss modulation frequency can be adjusted to bring the laser back into mode lock.

Abstract: A method and apparatus are provided for monitoring an optical signal from a solid state laser. The method includes the steps of providing a planar substrate defined by opposing planar surfaces and a substrate edge that together define a substrate volume that is transparent to an optical signal from the solid state laser, disposing the solid state laser on one of the opposing planar surfaces the planar substrate such that a first portion of the optical signal travels directly through the planar substrate substantially orthogonal to the opposing planar surfaces and a second portion of the optical signal is reflected between the opposing planar surfaces of the planar substrate and passes out of the substrate through the substrate edge, and disposing an optical detector proximate the edge of the planar substrate to detect the second portion of the optical signal.

Abstract: A light emitting element driving circuit for supplying driving current I2 to a light emitting element 10 connected to one line 2 of a current mirror circuit 12 is equipped with a pulse generating circuit 20 connected to the other line 1 so that pulse current flows therethrough, and superposing means 30 for superposing a first auxiliary pulse current on the pulse current in synchronization with the rise-up time of the pulse current. The rise-up time is shortened by the superposition. In the driving circuit, a source follower circuit is connected to the current mirror circuit, and current flowing through the source follower circuit is set to be substantially proportional to current flowing through the other line of the current mirror circuit.

Abstract: The present invention provides the following designing method: in a laser diode module or a depolarized laser diode module which has one laser diode and one polarization maintaining fiber connected to the output side thereof, the length of the polarization maintaining fiber is a value obtained by calculation of equation 37 with use of a longitudinal mode spacing ??output light from the Fabry Perot (FP) laser diode, an oscillating center wavelength ?0 of the laser light, a beat length LBeat 1 of the polarization maintaining fiber and an optical wavelength ?Beat used in the measurement of the LBeat 1.