Abstract: Compactness is preserved while enabling beam monitoring of optical properties of an output beam by employing a combination of reflection and diffraction. An input beam is reflected, divided using reflection/diffraction, and re-reflected. As a consequence, both a light source and one or more beam monitoring detectors may be disposed along a single side of an optical module. In one embodiment, an input beam is introduced from a first side of an optical module, is reflected by a 45 degree mirror, and is divided by a diffraction grating which redirects a minor portion of the beam energy back to the 45 degree mirror. Following the second reflection from the mirror, the returned portion of the beam is used to measure one or more optical properties.

Abstract: A control method for a laser diode is conducted such that optical output and OMA (optical modulation amplitude) or extinction ratio of the laser diode are controlled while modulating the optical output of the laser diode by applying a bias current and a modulation current to the laser diode. The method has: a first step of measuring the optical output of the laser diode; a second step of measuring a slope efficiency or a corresponding value of the slope efficiency while conducting APC (automatic power control) to adjust the bias current such that the optical output coincides with a predetermined value; and a third step of adjusting the modulation current by AAC (automatic amplitude control) according to the slope efficiency or the corresponding value of the slope efficiency such that the OMA or extinction ratio coincides with a predetermined value.

Abstract: An optical module includes a light source, a variable transmittance member disposed on a light path of output light from the light source distant from the light source, and a coupling section for coupling the output light from the light source via the variable transmittance member, wherein coupling efficiency as a ratio between intensity of the light from the light source and intensity of light to be coupled to the coupling section rises in conjunction with a rise in temperature.

Abstract: A system for assisting in observing a celestial object and providing synthetic guide star generation. A lasing system provides radiation at a frequency at or near 938 nm and radiation at a frequency at or near 1583 nm. The lasing system includes a fiber laser operating between 880 nm and 960 nm and a fiber laser operating between 1524 nm and 1650 nm. A frequency-conversion system mixes the radiation and generates light at a frequency at or near 589 nm. A system directs the light at a frequency at or near 589 nm toward the celestial object and provides synthetic guide star generation.

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: Laser processing methods, systems and apparatus having a super-modulating power supply or pumping subsystem and high beam quality (i.e., brightness) are disclosed. The methods, systems and apparatus have significant benefits, improved operation characteristics and material processing capability over currently available methods, systems and apparatus. In at least one embodiment, the beam quality of a high power solid state laser is improved in the presence of thermal lensing. High power laser cutting, scribing, and welding results are improved with a combination of modulation and high beam quality while providing for improved processing speeds.

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: An optical pulses emitter includes a first and a second Fabry-Perot laser diodes. The first and second laser diodes have a first and second working optical wavelength band respectively, and the first and second working wavelength bands has at least an overlapped wavelength band. The emitter also includes a signal source in connection with the first laser diode such that a plurality of optical pulses over the first working optical wavelength band is generated and an optical filter for filtering the optical pulses so as to output a plurality of optical pulses primarily of a desired optical wavelength, which falls into the overlapped wavelength band. The emitter further includes an optical amplifier along an optical path between the first and second Fabry-Perot laser diodes for amplifying the optical signals passing therethrough.

Abstract: A data recording/reproducing apparatus wherein various data to be used for maintenance are measured, and parameters required for analysis of the maintenance data are prerecorded to realize prediction of the service life of a semiconductor laser and detection of occurrence of any trouble that may be derived therefrom. In this apparatus where data are recorded in and/or reproduced from a recording medium, the internal state of the apparatus is measured, then any abnormal state in the apparatus is detected on the basis of abnormal state decision data, and the detected state is transmitted to an external information processor. The apparatus comprises a means for measuring first data relative to the apparatus; a first memory means for storing second data to make a decision as to an abnormal state of the measured first data; a means for generating third data relative to maintenance of the apparatus on the basis of the first and second data; and an output means for delivering the third data as an output.

Abstract: A laser transmitter includes an input stage generating an input signal to a limiting amplifier, the limiting amplifier generating an input signal to a laser driver, and the laser driver generating an input signal to a light source. The limiting amplifier has a control terminal for receiving a control signal that sets an amplitude characteristic of the input signal to the laser driver. The amplitude characteristic may be a common-mode or a peak amplitude of the input signal to the laser driver.

Abstract: A controller for controlling a light emitting diode (LED) light engine. The controller includes a temperature sensor configured to sensor temperature at the LED light engine. A current sensor senses a drive current of the LED light engine. A voltage differential sensor senses a voltage differential across LEDs of the LED light engine. A timer monitors a time of operation of the LED light engine. Further, a control device controls the drive current to the LED light engine based on the sensed temperature, the sensed drive current, the sensed voltage differential, and the monitored time of operation. Further, the control device outputs an indication of intensity degradation of an LED, and if the intensity degradation exceeds a predetermined threshold the control can output an indication of such to a user, so that the user can be apprised that the LED needs to be changed.

Abstract: The laser light generator control circuit comprises a load section, a control section, a bias current circuit section, and a modulation current circuit section. The load section generates a monitor voltage V1 that corresponds to the optical current corresponding to the amount of light received by a monitor light receiving element for receiving light from the laser light generator. The control section selects a combination (Db, Dm) in accordance with the result of comparing a value corresponding to the monitor voltage V1, and a reference value, from a group of combinations (Db, Dm)n that comprises a plurality of combinations (Db, Dm) of a value Db that corresponds to the bias current and a value Dm that corresponds to the modulation current, these combinations being specified so that the light emission power and the extinction ratio are constant, and generates a first control signal V2 and a second control signal V3 on the basis of the selected combination (Db, Dm).

Abstract: Laser processing methods, systems and apparatus having a super-modulating power supply (6) or pumping subsystem (5) and high beam quality (i.e., brightness) are disclosed. The methods, systems and apparatus have significant benefits, improved operation characteristics and material processing capability over currently available methods, systems and apparatus. In at least one embodiment, the beam quality of a high power solid state laser (2) is improved in the presence of thermal lensing. High power laser cutting, scribing, and welding results are improved with a combination of modulation and high beam quality while providing for improved processing speeds.

Abstract: The present invention provides an optical module that clears the restriction of the arrangement of the lead terminal. The present optical module includes a CAN-type package having a stem, the thermoelectric device and a light-emitting device. The thermoelectric device is mounted on a front side of a sub-mount that protrudes form the stem. Lead terminals are co-axially disposed so as to surround the sub-mount. The optical module further contains extension members to connect electrically the thermoelectric device disposed in the front side of the sub-mount to lead terminals disposed behind the sub-mount.

Abstract: An adjustable bipolar current source for a load, such as a thermoelectric cooler, includes a voltage-controlled power supply having a unipolar output, and an H-bridge. At least one of the two active elements on a first side and at least one of the two active elements on a second side of the H-bridge comprises an active conductive element responsive to a control signal to set a magnitude of current flow through the active conductive element. Control logic provides the control signals to the active elements on the first and second sides to set the polarity of the current to the load. Logic coupled to the voltage-controlled power supply maintains a supply voltage sufficient to maintain a voltage drop across the active conductive elements within a linear range of operation of the conductive elements. The output of the voltage-controlled power supply is clamped at or near a minimum stable level.

Abstract: A method and apparatus of using an input signal from a single-transverse mode vertical-cavity surface-emitting laser (VCSEL) with a multimode fiber (MMF) link to enable improved stabilization in time variation and improved modal dispersion of the output signal to facilitate the use of adaptive equalization techniques. The improvement results from using a conditioned launch of the input signal from the VCSEL into the MMF link. The increase in performance may be measured by the improved impulse response and an improved bandwidth-distance product of the MMF link.

Abstract: The method according to the present invention includes the steps of splitting an optical signal into first and second optical signals, increasing the pulse widths of the first optical signal to obtain waveform shaped light, generating clock pulses according to the second optical signal, and inputting the waveform shaped light and the clock pulses into an optical AND circuit 10 to obtain a converted optical signal. According to the present invention, it is possible to suppress amplitude noise or the like generated in the optical AND circuit due to the jitter or temporal instability of the optical signal and the clock pulses.

Abstract: The invention pertains to a driving device, for a light-emitting component, which can be universally used and is user-friendly. The driving device for a light-emitting component, particularly for a laser, includes an interface device for inputting a control signal selecting an operating mode of the component. It further includes a control device connected to the interface device, which drives the component with a predetermined operating-mode and temperature-dependent bias current and/or a predetermined operating-mode and temperature-dependent modulation current depending on the operating mode selected and depending on the temperature present at the component or on a temperature proportional thereto.

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 control system architecture that allows a semiconductor laser to be stabilized with respect to critical parameters, such as output power and/or emission wavelength, with a reduced cost with respect to the components required to implement control, while simultaneously maintaining or increasing precision of the control function. This is achieved using sophisticated integrated circuitry contained within the laser package to measure data related to multiple laser operation parameters and to transmit these parameters to a control circuit. In particular, precision thermal measurements may be used to eliminate the need for optical detectors in the laser package. The invention described herein has significant utility for different types of semiconductor lasers, including both edge emitting and VCSEL-type semiconductor lasers.

Abstract: An electronic device such as a laser diode is mounted on a heatsink assembly within a TO-can package. The heatsink assembly is mounted in heat exchange relation with a heat pipe by being on or adjacent a heat pipe. The heat pipe is either attached to an exterior face of the TO-can package or passes into the TO-can package to efficiently draw heat away from the heatsink assembly.

Abstract: A method and circuit for measuring the optical modulation amplitude in the operating region of a laser diode is described. The method utilises two measurements of OMA, each measurement being related to the slope in a specific portion of the operating region of the power/current characteristic curve of the laser diode. By combining the two measurement values, the invention provides a 1 measurement for OMA in the operating region of the laser diode that allows for the presence of a non-linear response in the region.

Abstract: A laser gain medium having a layered coating on at least certain surfaces of the laser gain medium. The layered coating having a reflective inner material and an absorptive scattering outside material.

Abstract: An optical device has a first medium that produces more photons that exit the first medium than enter the first medium, such as a gain material. A second medium that produces light of a different wavelength than the wavelength of light incident thereon, such as a second harmonic generator. The optical device defines a cavity including the first medium and the second medium. An energy source provides energy to at least one of the first medium and the second medium so that light exits the cavity, the energy source is modified in a number of different manners such that the optical device has decreased noise output.

Abstract: A laser used in a DWDM optical-fiber application is controlled so that, before it is powered up or down, its output power is maximally attenuated, the result being minimal cross-channel interference due to out-of-spec. wavelength. Laser control is further characterized by the steps of: (a) with laser current at zero, establishing a desired temperature of operation of the laser; (b) with output attenuation at maximum, increasing the current and regulating it to a level at which the design operating wavelength is achieved, and (c) decreasing the attenuation until the desired output power to the optical-fiber link is attained. Maximum attenuation is preferably applied during step (a).

Abstract: The present invention relates to a laser apparatus comprising a laser light emitting optical system for emitting laser light to a surface, a power stabilizing system for stabilizing the laser light power with a predetermined power interval, and a deflection system for deflecting light reflected from the surface away from the power stabilizing system. Thereby, the power stabilizing system will not erroneously regulate the power due to reflections from the surface to be treated. Furthermore, the invention relates to a method for treating an animal, including a human being, for a laser light treatable disease using the laser apparatus on the skin or the mucosa of the animal and allowing laser light to be emitted from the laser light emitting optical system to the skin or mucosa.

Abstract: A data recording/reproducing apparatus wherein various data to be used for maintenance are measured, and parameters required for analysis of the maintenance data are prerecorded to realize prediction of the service life of a semiconductor laser and detection of occurrence of any trouble that may be derived therefrom. In this apparatus where data are recorded in and/or reproduced from a recording medium, the internal state of the apparatus is measured, then any abnormal state in the apparatus is detected on the basis of abnormal state decision data, and the detected state is transmitted to an external information processor. The apparatus comprises a means for measuring first data relative to the apparatus; a first memory means for storing second data to make a decision as to an abnormal state of the measured first data; a means for generating third data relative to maintenance of the apparatus on the basis of the first and second data; and an output means for delivering the third data as an output.

Abstract: A device (10) for producing high frequency radiation using a source of elliptically polarized radiation is disclosed based on: irradiating a frequency multiplication medium having a screw axis (16) symmetry of approximate Nth order symmetry, oriented so that said elliptically polarized radiation propagates in parallel to the screw axis (16). Also, a method for producing high frequency radiation is disclosed based on irradiating a frequency multiplication medium having a screw axis (16) of approximate Nth order symmetry with elliptically polarized radiation so that the elliptically polarized radiation propagates in parallel to the screw axis (16). Furthermore, a method of producing a beam of high frequency radiation composed of only a limited number of wavelengths is disclosed whereby the intensity of a beam (22) interacting with a frequency multiplication medium is selected so that only a limited number of wavelengths is emitted.

Abstract: An ultra-broadband, variable and multiple wavelength, waveform shaping apparatus is disclosed that excels with the ability to yield light pulses shaped in waveform, variable and multiple in wavelength over an ultra-broad bandwidth, the pulses being as short as in the order of pico-seconds or less, or even in the order of femto-seconds.

Abstract: To achieve strong-illumination and weak-illumination of a laser beam onto a photo-sensitive drum, a laser control device controls an LD drive current switching circuit to switch between drive currents generated by an LD-bright-lighting current drive control circuit and drive currents generated by an LD-dim-lighting current drive control circuit, and applies the selected drive currents to a semiconductor laser element. The laser beam from the semiconductor laser element is detected by a photodiode, and the drive current is adjusted by feedback control based on the detected optical intensity. Since a detection signal from the photodiode is amplified not only when the laser beam is illuminating strongly but also when the laser beam is illuminating weakly, even tiny variations in the optical intensity during weak illumination can be detected clearly and can be reflected in feedback control.

Abstract: A hybridized optoelectronic device having a multi-section laser and a wavelength measuring component such that stable operational characteristics remote from mode boundaries may be determined and stored in a look-up table. A fast means of characterizing the device using sampling techniques is also disclosed. The device may incorporate a frequency-locking component to enable the laser to emit radiation at predetermined frequencies.

Abstract: A driver circuit for a laser diode or other optical source includes an input stage, an output stage, a current generator circuit and an output load detection circuit. The current generator circuit is adapted to establish a modulation current for application to one of a first output and a second output of the output stage in accordance with a differential or single-ended input data signal applied to the input stage. The output load detection circuit has first and second inputs coupled to the respective first and second outputs of the output stage, and is configured to detect an improper load condition at one or more of the first and second outputs of the output stage and to generate a corresponding output indicator. The output indicator is utilized in the driver circuit to control the modulation current so as to prevent saturation of the output stage in the presence of the improper load condition.

Abstract: A method and apparatus of using an input signal from a single-transverse mode vertical-cavity surface-emitting laser (VCSEL) with a multimode fiber (MMF) link to enable improved stabilization in time variation and improved modal dispersion of the output signal to facilitate the use of adaptive equalization techniques. The improvement results from using a conditioned launch of the input signal from the VCSEL into the MMF link. The increase in performance may be measured by the improved impulse response and an improved bandwidth-distance product of the MMF link.

Abstract: An optoelectric module includes a cylindrical ferrule defining an optical axis and having a first end constructed to receive an optical fiber aligned along the optical axis. A TO-can is positioned within the ferrule and has a first end with an optical element therein for conducting light therethrough. A base is affixed to the second end of the TO-can and to the second end of the ferrule. A laser is mounted within the TO-can so that light generated by the laser is directed through the optical element along the optical axis. A laser driver is mounted on the base and electrically connected to the laser. External connections to the laser driver are completed by either electrical traces on a surface of the base, vias through the base, or flexible leads mounted on the base.

Abstract: An IAU laser is stabilized to reduce intensity fluctuations. The laser comprises an IAU gain medium disposed in an optical resonance cavity and a multiphoton absorbing medium disposed in the cavity to reduce intensity fluctuations. A pump source to excite the gain medium is coupled to the cavity. In operation, the multiphoton absorbing material absorbs primarily at high intensity levels, effectively increasing the loss at high intensities. In an advantageous embodiment, the active medium comprises erbium-doped glass and the multiphoton absorber comprises a body of semiconductor exhibiting two-photon absorption at the emission wavelength.

Abstract: An apparatus and method for flexibly and precisely varying temporal placement and duration of pulses, within a train of high speed, high power optical pulses. The invention includes optics adapted for focusing on a layer of an information storage media. An optical pulse generator is coupled with the layer through the optics for generating a train of optical pulses, wherein each pulse has a respective temporal placement within the train and has a respective pulse duration. The respective pulse duration of each pulse is controlled by an amount of an analog duration control voltage, in accordance with a WRITE STRATEGY, which is based on a physical property of the layer of the information storage media. Similarly the respective temporal placement of each pulse is controlled by an amount of an analog temporal placement control voltage, in accordance with the WRITE STRATEGY.

Abstract: Method to measure gain of a photonic inverter based on a semiconductor laser using two different modes of operation. In one mode, the device is operated as a photonic inverter device and in the other mode as a photogenerated current measurement device. While the device is operated in a photonic inverter mode, that is, pumped at a magnitude that supports photonic inverter operation, the optical output power is measured in the absence of an input signal and with an input signal that quenches the output of the photonic inverter. While the device is operated as a photogenerated current measurement device with an input optical signal, a reverse bias is applied to offset any forward bias induced by the injected input optical signal, the induced photocurrent is measured, and the wavelength of the input optical signal is measured.

Abstract: A multichannel WDM transmission system incorporates a plurality of WDM optical sources with stabilized wavelengths and light intensity. Efficient stabilization of these characteristics is achieved by modulation of WDM sources by distinguishing low frequency electrical signals in a range between 1 and 4 kHz and modulation depth in a range between 1% and 5% that are used as WDM source identifiers. After the modulated outputs of the WDM sources are multiplexed and filtered, a Fourier transform of total light intensity may be obtained. Digital feedbacks provide stabilization of both the wavelength and light intensity of each WDM optical source.

Abstract: The laser drive device of this invention includes a laser, first and second current sources, a current amplifier, and first and second transistors. When the first transistor is OFF, a first current from the first current source is supplied to the current amplifier, where the current is amplified to generate a laser current to be supplied to the laser. Thus, the laser is turned ON. During this time, the second transistor is ON, allowing a second current to flow from a power supply node into the second current source. When the first transistor is ON, the entire or part of the first current flows into the second current source through the first transistor. This reduces the current supplied to the current amplifier and thus the laser current, resulting in turning OFF the laser. During this time, the second transistor is OFF. The values of the first and second currents are determined by a set current value.

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: A system for assisting in observing a celestial object and providing synthetic guide star generation. A lasing system provides radiation at a frequency at or near 938 nm and radiation at a frequency at or near 1583 nm. The lasing system includes a fiber laser operating between 880 nm and 960 nm and a fiber laser operating between 1524 nm and 1650 nm. A frequency-conversion system mixes the radiation and generates light at a frequency at or near 589 nm. A system directs the light at a frequency at or near 589 nm toward the celestial object and provides synthetic guide star generation.

Abstract: In a semiconductor laser diode module including a semiconductor laser diode having a front facet for emitting a light beam, a collimating lens for receiving the light beam to generate a collimated light beam and a coupling lens for receiving the collimated light beam and converging the collimated light beam to an optical fiber, a bandpass filter is provided for receiving a first part of the collimated light beam, and a light detector is provided to have a first portion for receiving the first part of the collimated light beam through the bandpass filter and a second portion for receiving a second part of the collimated light beam. Thus, a wavelength of the semiconductor laser diode is controlled in accordance with an output signal of the first portion of the light detector, and a light intensity of the semiconductor laser diode is controlled in accordance with an output signal of the second portion of the light detector.

Abstract: A device to monitor light output from a light source, including a V-groove substrate with a reflective coating deposited on at least one surface, an optical fiber, a light source positioned so that an amount of the light emitted, which is less than 100%, enters the optical fiber, a light intensity or source detector positioned so that at least some of the light emitted from the light source, that did not enter the optical fiber impinges upon the light intensity detector, and feedback circuitry. A method of producing a device including the steps of coating a surface of a V-groove substrate with a reflective material, placing a light source in said V-groove substrate.

Abstract: A directly modulatable laser comprising an active medium inside a laser cavity formed by a resonator mirror and an out-coupling mirror, and a pump light source exciting the active medium. It is characterized in that the active medium generates radiation of two wavelengths (&lgr;1 and &lgr;2) and the resonator mirror is constructed as a controllable reflector by which the reflectivity is controllable for each of the two wavelengths (&lgr;1 and &lgr;2) and the controllable reflector is connected with a control unit, wherein the reflection factor is controlled in such a way that the inversion density of the electrons which is generated in the active medium is constant and the light output of one of the wavelengths ((&lgr;1) is controllable between a minimum value and a maximum value according to an applied control signal, wherein the control of the two wavelengths ((&lgr;1 and &lgr;2) is carried out in push-pull.

Abstract: Optical chirped return-to-zero (CRZ) data signals are generated without the need for a separate phase modulator, by using a dual-drive Mach-Zehnder modulator for RZ pulse carving that is driven with two typically sinusoidal signals of either unequal amplitude or unequal relative phase, i.e. of non-vanishing phase difference.

Abstract: Photonic arbitrary waveform methods and generation by manipulating the phase-locked longitudinal modes of an approximately 12.4 GHz fundamentally modelocked external-cavity semiconductor laser are demonstrated. Photonically synthesized sine waves (center frequency of approximately 37.2 GHz, linewidth less than approximately 100 Hz, dynamic range approximately 50 dB at approximately 100 Hz resolution bandwidth) and complex, arbitrarily shaped optical/microwave frequency waveforms with instantaneous bandwidths up to approximately 75 GHz are shown. A WDM filter can be used to separate individual longitudinal modes of a modelocked laser. Photonic arbitrary generation occurs through the modulation of individual channels before recombining the channels, followed by amplifying the output.

Abstract: A servo technique for concurrently providing wavelength locking and stimulated Brillouin scattering (SBS) suppression in an external cavity laser. Respective wavelength locking and SBS suppression signals are generated by a controller and combined into a composite drive signal. The composite drive signal is used to drive an optical path length adjustment element to modulate the optical path length of the laser cavity. The wavelength locking and SBS suppression portions of the drive signals produce concurrent modulations of the laser optical path length having different modulation frequencies and causing different frequency (wavelength) excursions. These modulations produce corresponding wavelength and intensity amplitude modulations in the laser's output. A feedback signal indicative of the intensity amplitude modulations is filtered to attenuate the portion of the signal due to the SBS suppression modulation, and is received as a tuning feedback signal by the controller.

Abstract: A semitransparent mirror is utilized to reflect a laser light emitted from a semiconductor laser component used for a light source for an optical disc such as DVD-RAM, and a photo detector receiving the laser light having passed therethrough for monitoring with FAPC system is positioned behind the mirror. Furthermore, a transparent medium layer with a predetermined thickness is provided between the semitransparent mirror and the photo detector. Thanks to the transparent medium layer, the returned extra light from the DVD-RAM does not enter the photo detector and deviates therefrom, after it has passed through the semitransparent mirror.

Abstract: A tuning element tunes an optical component by adjusting the length of an optical fiber used within the optical component. Changes in length of a piezoelectric element are amplified by a surround structure, and the surround is provided with optical fiber fixing portions. The piezoelectric element is provided with an opening for receiving a fiber, such that a portion of a fiber can pass transversely through the opening, the length of the portion being adjustable by controlling the length of the piezoelectric element. The piezoelectric actuators have a fast response time and provide reliable operation.

Abstract: The present invention relates to a method, device, and system for waveform shaping of signal light. The device for waveform shaping of signal light according to the present invention includes a distributed feedback (DFB) laser having a stop band defined as the range of wavelengths allowing laser oscillation, and a drive circuit for supplying a drive current to the DFB laser so that the DFB laser oscillates at a first wavelength included in the stop band. Signal light having a second wavelength not included in the stop band is input into the DFB laser. In the case that the signal light is provided by optical pulses each having a high level and a low level, amplitude fluctuations at the high level of the signal light can be effectively suppressed by suitably setting the power of the signal light.