Abstract: A wavelength tunable laser module for DWDM is used, in which a single electroabsorption modulator integrated laser is mounted and an oscillation wavelength is made tunable by temperature control. Driving conditions of a laser and a modulator are determined such that they have approximately the same modulation and transmission characteristics in a temperature control range. Such an electroabsorption modulator integrated laser is used and the driving conditions are incorporated, thereby a small, inexpensive wavelength tunable optical transmitter can be provided.

Abstract: According to one embodiment of the present invention, an optical package comprises one or more semiconductor lasers coupled to a wavelength conversion device with adaptive optics. The optical package also comprises a package controller programmed to operate the semiconductor laser and the adaptive optics based on modulated feedback control signals supplied to the wavelength selective section of the semiconductor laser and the adaptive optics. The wavelength control signal supplied to the wavelength selective section of the semiconductor laser may be adjusted based on the modulated wavelength feedback control signal such that the response parameter of the wavelength conversion device is optimized. Similarly, the position control signals supplied to the adaptive optics may be adjusted based on the modulated feedback position control signals such that the response parameter of the wavelength conversion device is optimized.

Abstract: A laser diode device capable of obtaining high light efficiency and improving output by using an AlGaInN compound semiconductor as a material is provided. The laser diode device includes semiconductor layer which has an active layer and is made of a nitride Group III-V compound semiconductor containing at least one of aluminum (Al), gallium (Ga), and indium (In) among Group 3B elements and nitrogen (N) among Group 5B elements. The active layer has a strip-shaped light emitting region whose width W is from 5 ?m to 30 ?m, length L is from 300 ?m to 800 ?m, and output of laser light from the active layer is 200 mW or more.

Abstract: Semiconductor lasers are driven such that high output laser beams are stably obtained without a long start up time. A method for driving semiconductor lasers by automatic current control or automatic power control with a constant current source involves the steps of: generating a pattern of drive current values for the semiconductor lasers, which is defined according to the amount of time which has elapsed since initiating driving thereof, that enables obtainment of substantially the same light output as a target light output by the automatic current control or the automatic power control; and varying the drive current of the semiconductor lasers in stepwise increments according to the pattern for a predetermined period of time from initiation of drive thereof. A single pattern is used in common to drive the plurality of semiconductor lasers.

Abstract: The present invention relates generally to semiconductor lasers and laser projection systems. According to one embodiment of the present invention, a method of correcting output power variations in a semiconductor laser is provided. According to the method, an output power feedback loop is utilized to generate optical intensity feedback signals representing actual output power of the laser source for discrete portions V1, Vi, . . . Vj of the image signal. Error signals E1, Ei, . . . Ej are generated representing the degree to which actual projected output power varies from a target projected output power for the discrete portions V1, Vi, . . . Vj of the image signal. These error signals E1, Ei, . . . Ej are utilized to apply corrected control signals G1?, Gi?, . . . Gj? to the gain section of the semiconductor laser for projection of compatible discrete portions V1?, Vi?, . . . Vj? of the image signal.

Abstract: A method for improving spectral, spatial, and temporal stability of semiconductor lasers and their beam profile uniformity based on statistical average of plural transient or unsteady state longitudinal and lateral modes that are continuously perturbed. A laser module implementing the method comprises a semiconductor laser, a drive circuit generating RF-modulated drive current, and an automatic power control loop for producing stable, low noise and uniform or nearly uniform illumination field along one or two dimensions.

Abstract: A power monitoring and correction to a desired power level of a laser or group of lasers utilizes two photodetectors which are employed to accurately determine the amount of output power from the front end or “customer” end of a laser or a plurality of such lasers. During power detection, which may be accomplished intermittently or continuously, the laser is modulated with a tone of low frequency modulation. One photodetector at the rear of the laser is employed to detect the DC value of the frequency tone, i.e., a value or number representative of the AC peak-to-peak swing, amplitude or modulation depth of the tone. Also, the rear photodetector may be employed to determine the optical modulation index (OMI). In either case, these values may be employed in a closed loop feedback system to adjust or otherwise calibrate the value of the low tone frequency relative to the total desired bias current applied to the laser.

Abstract: Various laser drivers and methods are provided. In one embodiment, a laser driver is provided that comprises a laser driver circuit having a common anode portion and a common cathode portion. The common anode portion and the common cathode portion are each configured to drive a laser. Also, the laser driver includes a control input to alternatively enable one of the common anode portion and the common cathode portion to drive the laser.

Abstract: A drive signal for driving a semiconductor laser is generated on the basis of an image signal inputted in synchronism with a pixel clock. A bias signal to the semiconductor laser is generated at a timing earlier than the drive signal by a predetermined time. The bias signal is disabled in synchronism with the leading edge of the drive signal.

Abstract: A laser diode illuminator device and a method for optically conditioning the output beam radiated from such a device, so that highly-demanding illumination application requirements that call for high output powers within a specified field of illumination can be addressed. At the heart of the device is a two-dimensional stack of laser diode bars wherein the linear array of beamlets radiated by each laser diode bar is optically conditioned through its passage in a refractive-type micro-optics device followed by a cylindrical microlens. The micro-optics device performs collimation of the linear array of beamlets along the fast axis of the bars, and it also acts as a beam symmetrization device by interchanging the divergences of the laser beamlets along the fast and slow axes. The cylindrical microlens is for collimation of the beamlets along the slow axis.

Abstract: A circuit for detecting optical failures in a passive optical network (PON) wherein digital burst data transmitted by an optical transmitter is monitored by a photodiode, includes a power determination unit coupled to the photodiode for providing measurements of an output optical power of a high logic level and a low logic level of the digital burst data during ON times of the optical transmitter and for providing a measurement of an output optical power during OFF times of the optical transmitter. A logic unit coupled to the power determination unit is responsive to the measurements for generating control and calibration signals. Such a circuit may be used for detecting rogue optical network unit (ONU) failure or eye safety hazards in a passive optical network (PON) wherein digital burst data transmitted by an optical transmitter is monitored by a photodiode.

Abstract: A light source and the method for operating the same are disclosed. The light source includes first and second lasers, and first and second wavelength control assemblies. The lasers emit first and second light beams, respectively, at wavelengths that are determined by first and second wavelength control signals. First and second beam splitters split the first and second light beams, respectively, to create first and second sampling light beams. The first and second wavelength control assemblies receive sampling light beams and generate the first and second wavelength control signals such that the wavelengths of the first and second light beams differ by no more than a predetermined amount. The first and second wavelength control assemblies each include an absorption cell having a gas that has an optical absorption that varies with the wavelength of the first and second sampling light beams at wavelengths around the output wavelength of the light source.

Abstract: A device contains at least one wavelength-tunable multilayer interference reflector controlled by an applied voltage and at least one cavity. The stopband edge wavelength of the wavelength-tunable multilayer interference reflector is preferably electrooptically tuned using the quantum confined Stark effect in the vicinity of the cavity mode (or a composite cavity mode), resulting in a modulated transmittance of the multilayer interference reflector. A light-emitting medium is preferably introduced in the cavity or in one of the cavities permitting the optoelectronic device to work as an intensity-modulated light-emitting diode or diode laser by applying an injection current. The device preferably contains at least three electric contacts to apply forward or reverse bias and may operate as a vertical cavity surface-emitting light emitter or modulator or as an edge-emitting light emitter or modulator.

Abstract: A dual output laser source provided on a substrate outputs light from a first and second output. A portion of the light generated by the laser is supplied to a first modulator via the first output. A second portion of the light generated by the laser is supplied to a second modulator via the second output. The first modulator is provided on the substrate and generates a first modulated signal. The second modulator is also provided on the substrate and generates a second modulated signal. Each output of the laser is used to provide continuous wave light sources to components on photonic integrated circuit.

Abstract: An optical module includes a semiconductor laser for output light with a wavelength, a temperature stabilization unit arranged for adjusting temperature of the semiconductor laser, and a controller for controlling a current injected to the semiconductor leaser by the use of a first function in accordance with changing of the wavelength on the bases of heat at the time of changing of the wavelength of the outputted light of the semiconductor leaser in a predetermined first period, and controlling the current injected to the semiconductor leaser by the use of a second function in accordance with changing of the wavelength on the bases of the temperature stabilization unit in a predetermined second period after the first period.

Abstract: A light source driving apparatus, which adjusts a bias current to be supplied so as to control intensity of a light source, comprises a power source which outputs a variable reference voltage; a light receiving unit which receives light output from the light source and converts the light into an electric signal; a bias supply unit which supplies a bias current, which is based on an intensity control signal according to the electric signal converted by the light receiving unit and the reference voltage output from the power source, to the light source; and a voltage control unit which acquires information about intensity characteristics with respect to the intensity control signal of the light source and controls the reference voltage according to the acquired information about the intensity characteristics.

Abstract: The present invention relates to the field of pulsed laser oscillators. It relates to a pulsed laser oscillator (15) for emitting a laser pulse, including a laser cavity (15), said laser cavity including a laser medium (4) able to be pumped by pump radiation emitted by at least one pump radiation source (5) and to emit laser radiation, said laser cavity (15) including seal means (7) able to seal said cavity for a period of sealing, characterized in that said seal means (7) are electro-optical seal means, and in that said seal means are able to be powered by a supply voltage, so that the duration of the pulse emitted is modified when the value of the supply voltage is modified.

Abstract: The present invention is to provide an LD-driver that enables to adjust the waveform of the driving current to the LD even the driver is constituted with a current controlled device such as bipolar transistor. The LD-driver of the invention provides a plurality of modulation current sources each having a function to set the amplitude, the phase and the pulse width of the current output independently. The LD is provided with the modulation current superposed with each current derived from respective current sources.

Abstract: A disclosed laser light intensity control device includes a semiconductor laser configured to scan a photoconductor by emitting laser beams and form an electrostatic latent image, a temperature detection circuit configured to detect a temperature of the semiconductor laser, a light intensity detection circuit configured to detect a light intensity of the laser beams emitted from the semiconductor laser, a first drive circuit configured to supply the semiconductor laser with a first current that drives the semiconductor laser, a second drive circuit configured to supply the semiconductor laser with a second current that is superimposed on the first current, and a control circuit configured to control the first drive circuit and the second drive circuit.

Abstract: The invention discloses an optical transmission module with digital adjustment and method thereof. The module includes a laser (21), a laser driver (22), an automatic power adjustment circuit (23), an automatic temperature adjustment circuit (24), a digital adjustment circuit (25) and a memory (26). The digital adjustment circuit, consisted of a digital-to-analog converter or a digital adjustment potentiometer, receives a digital adjustment signal and outputs, respectively, a extinction ratio adjustment signal and a cross point adjustment signal to the laser driver, an optical power adjustment signal to the automatic power adjustment circuit and an optical wavelength adjustment signal to the automatic temperature adjustment circuit. The memory stores data, using for on-line adjustment of the optical transmission module, at least including parameters of said optical transmission module and said laser emitting optical power parameters, to be reported upward.

Abstract: A method of manufacturing a three-dimensional object is provided, in which the object is solidified layer by layer by solidifying a building material by means of a beam of a gas laser at locations in each layer corresponding to the cross section of the object, wherein the power of the laser is measured and the power of the laser is controlled according to the measured value, characterized in that the power measurement takes place in a time window, in which a change of the power occurs, and an input control signal of the laser is controlled according to the measured values.

Abstract: In the present invention, the extremely complicated setting and control and an extremely expensive optical component (wavelength locker) are not required, and optical output wavelength and optical output power can simply be set and controlled at a moderate price. At least one value for determining a dependence of the optical output wavelength on drive current and device temperature and at least one value for determining a dependence of the optical output power on drive current and device temperature in a light emitting device constituting first means 1 for emitting light are stored in fourth means 4.

Abstract: It is an object to enable control according to an optimum temperature condition for a wavelength conversion device.

Abstract: A method for monitoring laser light launched into a core of a single mode fiber includes launching a portion of light directly into the cladding about the core. The cladding launched light is a known fraction of the core launched light and can be monitored by placing a detector about the cladding. Detected light including light that was launched into the cladding and has leaked through the cladding is used as a known fraction of light in the core and can be used to control the laser light source. This can be done with a straight section of single mode optical fiber and does not require bending the fiber. Advantageously, most of the core launched light remains in the core as guided light.

Abstract: In a laser power control apparatus for controlling a laser power of a combination drive, first laser light Lc applied onto a first optical disk and second laser light Ld applied onto a second optical disk is collected by one photodetector 8.

Abstract: A method for controlling laser power of an optical pickup unit (OPU) includes: providing a first relationship between the laser power and a driving parameter, wherein the driving parameter is utilized for driving a laser diode (LD) of the OPU, and the first relationship corresponds to a first temperature; utilizing a temperature-related model to convert the first relationship into a second relationship between the laser power and the driving parameter, wherein the second relationship corresponds to a second temperature; and storing the first relationship for being utilized at the first temperature, and storing the second relationship for being utilized at the second temperature.

Abstract: An optical power control apparatus includes a changing unit which changes, a plurality of number of times, the value of a current flowing to an optical beam output apparatus, and an obtaining unit which obtains, in correspondence with each current value, a peripheral optical power representing an optical power at the peripheral part of the spot of the optical beam output from the optical beam output apparatus. The optical power control apparatus also includes a correction unit which corrects the peripheral optical power so that the peripheral optical power and a central optical power representing an optical power at the central part of the spot have an approximately linear relationship in correspondence with each current value. The optical power control apparatus also includes a control unit which controls the optical power of the optical beam output from the optical beam output apparatus in accordance with the corrected peripheral optical power.

Abstract: A light source emits a laser beam to the object through an output end. An optical system is placed between the output end and the object. The optical system adjusts the energy of the laser beam emitted, through the output end, onto a unit area for a unit time. The energy of the beam spot on the object enables cutting or bending of the object. The optical system serves to adjust the energy of the laser beam irradiated to the object. The energy of the laser beam instantly changes as compared with the case where the energy of the laser beam is adjusted based on a driving voltage applied to a laser oscillator. The object is thus processed by using the laser beam with high accuracy.

Abstract: According to one embodiment, an optical disk drive includes a monitor diode which monitors a laser output of a laser diode irradiating a laser beam to an optical disk, a detector which sets an output termination mode when a state that a monitor signal obtained from the monitor diode exceeds a first reference value continues over a predetermined period is detected from a deglitch, a switch section which terminates the laser output of the laser diode upon setting of the output termination mode, and a controller which supplying a drive signal for reducing a difference obtained as a comparison result between the monitor signal and a second reference value smaller than the first reference value. The controller serves as a software-based digital filter which realizes an equalizer function of making phase compensation of the comparison result.

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: The invention discloses a method and an apparatus for precise control of laser processing specifically for, but not limited to non-metallic substrate materials, said method comprising the steps of reading a constant and unbroken laser beam (4) energy power level from a laser cavity (3), and adjusting and modifying its input control signal to produce a significant improvement in power stability; ensuring thermal stability within an optical pulse modulation means (11), by either or a combination of maintaining the constant and unbroken laser beam energy from said laser cavity (3) into said optical pulse modulation means (11), by providing a stand-by modulation signal (12) to said pulse modulation means (11), by flowing cooling gas across the optical surfaces and, by maintaining a tight cooling control through the cooling medium; pre-calculating or Real-Time calculating the predictable changes in spot size, shape and area in combination with the required processing path direction movements and velocities at the

Abstract: A method and apparatus to automatically control an output power of a laser diode, include generating an error voltage between an output voltage of the laser diode sampled during an automatic power control period and a reference voltage, and performing proportional-integral processing on the error voltage to generate a compensated control voltage and applying the compensated control voltage to the laser diode.

Abstract: An optical communication module includes a semiconductor laser drive circuit configured to supply a drive current to a semiconductor laser so as to output a laser beam; a drive control section configured to control the semiconductor laser drive circuit based on an ambient temperature of the semiconductor laser such that the output light beam has a predetermined light level, and the drive current falls within a predetermined range. A light quantity adjusting section removes a part of the laser beam to produce an output light beam from a remaining portion of the laser beam when the laser beam passes through the light quantity adjusting section, and a quantity of the removed apart of the laser beam depends on a wavelength of the laser beam and an ambient temperature of the semiconductor laser.

Abstract: A method for generating a laser projection by employing a laser gain medium for receiving an optical input projection from a laser pump. The method further includes a step of employing a mode selection filter comprising an electro-optical (EO) tunable layer disposed between two parallel reflection plates for generating a laser of a resonant peak.

Abstract: There is provided a light receiving circuit capable of preventing an output variation of the light receiving circuit due to a change in ambient temperature with a simple configuration. The light receiving circuit is provided with a photodiode 4 for LD power monitoring and an I-V amplifier 5 connected with a feedback resistor 13, wherein a light receiving section 16 of the photodiode 4 is covered with a protective film 19. Temperature dependences between a light transmittance of the protective film 19 in accordance-with a shift of a wavelength of a laser beam due to a change in ambient temperature, and a resistance value of the feedback resistor 13 are set in such a way that they may be mutually compensated and an output voltage from the light receiving circuit may be constant for a temperature change.

Abstract: The present invention provides wavelength monitoring and/or control enabling size reduction and low power operation without requiring a complicated optical system in its wavelength monitoring and controlling mechanism. The measurement portion (1) measures temperature by a thermistor (5) in the measurement portion, and measures a bias current by using an LD drive current detecting circuit (6). The LD temperature, optical output and bias current are measured by the measurement portion. The relationship between the LD temperature and wavelengths or between the temperature, bias current and wavelengths is stored in a memory map of the storage portion (2). The central controlling portion (3) calculates wavelengths on the basis of the temperature and the bias current or the temperature information of the measurement portion, and the relationship between the LD temperature, bias current and wavelengths or between the temperature and wavelengths of the storage portion.

Abstract: A laser power control unit used for controlling the laser power of an optical pick-up unit (OPU) is provided. The laser power control unit includes: at least one analog-to-digital converter (ADC) electrically coupled to the OPU for transferring a front photodiode output signal into a digital feedback signal; and at least one digital control circuit electrically coupled to the ADC for generating a power control signal and outputting the power control signal to the OPU in order to control the laser power of the OPU. The digital control circuit has a compensation circuit used for generating a compensation value according to a difference between the digital feedback signal and a digital target feedback signal so as to adjust the power control signal. The front photodiode output signal corresponds to the laser power of the OPU.

Abstract: Embodiments of an optical detection apparatus are disclosed which may include one or more of a waveguide, a trench formed in the waveguide, a reflective surface, and a photodetector. The waveguide may be formed in a semiconductor substrate to propagate an optical signal received at a first end of the waveguide. The trench may also be formed in the waveguide having a first sidewall and a second sidewall, the first and second sidewalls forming first and second angles with the waveguide's propagation direction. The second sidewall may include a reflective surface formed thereon. The photodetector may be configured to receive an optical signal propagated in the waveguide, through the first sidewall and reflected from the reflective surface on the second sidewall.

Abstract: The present invention provides a method and apparatus, such as an integrated circuit, to control the optical midpoint power level and the extinction ratio of a semiconductor laser and maintain the optical midpoint power level and the extinction ratio substantially constant at corresponding predetermined levels. Apparatus embodiments include a semiconductor laser, a modulator, a photodetector, an optical midpoint controller, and an extinction ratio controller. The semiconductor laser is capable of transmitting an optical signal in response to a modulation current. The modulator is capable of providing the modulation current to the semiconductor laser, with the modulation current corresponding to an input data signal. The photodetector, which is optically coupled to the semiconductor laser, is capable of converting the optical signal into a photodetector current.

Abstract: An optical module includes a light emitting element, a connector part that supports one end of an optical fiber and optically couples the optical fiber to the light emitting element, and a monitoring light receiving element that has a characteristic to increase photosensitivity with an increase in an ambient temperature, and receives a part of components of light emitted from the light emitting element.

Abstract: A method embodiment of the invention includes a scheme for trimming and compensation of a laser emitter in a fiber optic link. A laser emitter is provided. Also a reference optical power value is determined using data models of laser emitter performance generated by statistical analysis of sample population of lasers that are similar to the subject laser emitter. The performance of the subject laser is measured and qualified optical power levels for the subject laser emitter are determined using the reference operating power value and measured performance of the subject laser emitter. The driving current of the subject laser emitter is adjusted to compensate for changes in temperature until the optical power of the subject laser emitter obtains a desired qualified optical power level. Related methods of determining qualified optical power levels for a laser emitter in a fiber optic link are also disclosed.

Abstract: A new and useful attenuating device and method for attenuating a polarized laser beam is provided. At least one attenuating optic is located along, and is rotatable about, a polarized laser beam axis, and is configured to transmit and to reflect portions of the polarized laser beam. The attenuating optic provides predetermined attenuation of the polarized laser beam by changing the ratio between transmission and reflection of the polarized laser beam as a function of the incidence of the polarized laser beam on one or more partially reflective surfaces of the attenuating optic. The attenuating optic is rotatable about the polarized laser beam axis to control the incidence of the polarized laser beam on the one or more partially reflective surfaces of the attenuating optic, thereby to control the ratio between transmission and reflection of the polarized laser beam and provide a range of attenuation of the polarized laser beam.

Abstract: An automatic power control system provides a control signal that regulates the output power of at least one laser diode. Coarse adjustment of the control signal is provided by a first means, preferably a digital variable resistor, while fine adjustment and compensation is provided by a second means, preferably by a digital-to-analog converter that receives an input signal proportional to a sensed control system parameter. The control system includes an operational amplifier having a first input coupled to sense output power, and a second input coupled to a DAC to provide finer resolution control. Memory can store system parameter or system parameter variations that can be coupled to the DAC and/or variable resistor to enhance system stability over ambient variations.

Abstract: Embodiments of an optical detection apparatus are disclosed which may include one or more of a waveguide, a trench formed in the waveguide, a reflective surface, and a photodetector. The waveguide may be formed in a semiconductor substrate to propagate an optical signal received at a first end of the waveguide. The trench may also be formed in the waveguide having a first sidewall and a second sidewall, the first and second sidewalls forming first and second angles with the waveguide's propagation direction. The second sidewall may include a reflective surface formed thereon. The photodetector may be configured to receive an optical signal propagated in the waveguide, through the first sidewall and reflected from the reflective surface on the second sidewall.

Abstract: Laser modulation is controlled by using a measurement of the average output power level of the laser to adjust the amplitude of the modulation current as necessary to prevent the laser from being over- or under-modulated and to adjust the amplitude of the bias current as necessary to maintain the average output power level of the laser at a desired, reasonably constant level. The laser controller receives an electrical feedback signal from a laser output power monitoring device and uses this signal to obtain the measurement of the average output power level of the laser. Based on this measurement, a bias current control signal and a modulation current control signal are generated and output to the laser driver to cause the laser driver to set the amplitude of the bias current to achieve a desired average output power level and to set the amplitude of the modulation current to prevent over- and under-modulation.

Abstract: Disclosed is a system (10) for regulating the power of a laser beam (12).

Abstract: This invention relates to the stabilization of a laser source used in optoelectronics, specifically a source comprising a semiconductor laser diode (1). Such laser sources are often used as so-called pump lasers for fiber amplifiers in the field of optical communication, erbium-doped fiber amplifiers being a prominent example. Such lasers are usually designed to provide a narrow bandwidth optical radiation with a stable power output in a given frequency band. The present invention now concerns such a laser source using external reflector means, preferably consisting of one or more appropriately designed fiber Bragg gratings (9), providing very high relative feedback with an extremely narrow bandwidth, combined with a very long external cavity encompassing about 100 modes or more and an extremely low front facet (2) reflectivity of the laser diode. This stabilizes the laser source extremely well in its operation, without the need for an active temperature stabilizing element.

Abstract: An object of the present invention is obtaining a semiconductor film with uniform characteristics by improving irradiation variations of the semiconductor film. The irradiation variations are generated due to scanning while irradiating with a linear laser beam of the pulse emission. At a laser crystallization step of irradiating a semiconductor film with a laser light, a continuous light emission excimer laser emission device is used as a laser light source. For example, in a method of fabricating an active matrix type liquid crystal display device, a continuous light emission excimer laser beam is irradiated to a semiconductor film, which is processed to be a linear shape, while scanning in a vertical direction to the linear direction. Therefore, more uniform crystallization can be performed because irradiation marks can be avoided by a conventional pulse laser.

Abstract: A method of performing eye safety measurements on laser devices is disclosed. The laser is contained within a housing having a central bore. The method uses an optical detector having at least two zones to make separate measurements of both a direct power coming from the laser and an indirect power reflected off of the central bore. The first zone measuring the direct power is smaller than the second zone measuring the indirect power. The measurement of the first power is then used to adjust the power of the laser to be within a specified optical standard, such as the class 1 standard. In one exemplary embodiment, the laser is an 850 nanometer Vertical Cavity Surface Emitting Laser (VCSEL).

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.