Abstract: A monitored laser system has a laser having a first mirror; an exit mirror, at least a portion of a laser cavity defined by the first mirror and the exit mirror; and an active region located in the laser cavity, the active region containing a material that is capable of stimulated emission at one or more wavelengths of laser light within a tuning range of the laser. A multiple reflectivity band reflector (MRBR) is coupled to at least a portion of laser light emitted from the laser and transmits filtered laser light. The MRBR has a plurality of layers of material arranged in parallel such that the reflector has a plurality of reflectivity peaks within the tuning range, each reflectivity peak separated from neighboring reflectivity peak by a reflectivity trough having a trough minimum, said reflectivity peaks characterized by a peak profile and said trough minima between said reflectivity peaks characterized by a trough profile.

Abstract: A multiple reflectivity band reflector (MRBR) includes a stack of dielectric layers, arranged so that the reflector has a reflectivity profile comprising a plurality of reflectivity bands, e.g. at least first and second wavelength bands with reflectivity above a lasing threshold reflectivity, separated by a third wavelength band between the first and second wavelength bands having reflectivity below the lasing threshold reflectivity. A laser having at least a first mirror and an MRBR as the second mirror has a laser cavity, at least a portion of which is defined by the first mirror and the MRBR. An active region located within the laser cavity contains a material that is capable of stimulated emission at one or more wavelengths in the first and second wavelength bands. The gain spectrum of the laser is adjusted to select one of the first and second wavelength bands, thereby providing for lasing at a wavelength within the selected wavelength band. The laser may be, e.g.

Abstract: A monitored laser system includes a laser with a first mirror and an exit mirror. The laser also has a laser cavity defined at least in part by the first mirror and the exit mirror. Within the laser cavity is an active region that contains material that is capable of stimulated emission at one or more wavelengths such that laser light is emitted from the laser. A power source is coupled to the active region. A multiple reflectivity band reflector (MRBR) is coupled to at least a portion of the emitted laser light. The MRBR has at least first and second wavelength bands with reflectivity above a particular reflectivity separated by at least a third wavelength band having reflectivity below the particular reflectivity. A first photodiode is coupled to at least a portion of the filtered laser light and produces an output based on the amount and wavelength of light received.

Abstract: A planar lightwave circuit (PLC) module for conditioning light output from a tunable laser designed to generate light at a target wavelength. The PLC module has a substrate; a primary waveguide embedded in said substrate, said primary waveguide having an input end for receiving light from the tunable laser and an output end for outputting said light; and at least a first secondary waveguide embedded in said substrate, said first secondary waveguide receiving a first portion of said light from the tunable laser. A filter having a passband centered on the target wavelength is coupled to an output of the first secondary waveguide to receive said first portion of light, and generates a signal related to the intensity of said first portion of light in the passband centered on the target wavelength. This may be used by a processor and associated laser control circuitry for wavelength locking purposes.

Abstract: An embodiment of a surface-emitting laser structure includes a first semiconductor region of a first conductivity type coupled to a first contact and a second semiconductor region of the same conductivity type coupled to a second contact. A third semiconductor region of the opposite conductivity type is coupled to a third contact and interposed between the first and second semiconductor regions. An active region is interposed between the first and third regions. In a further embodiment, the laser structure may include a variable refractive index structure interposed between the second and third semiconductor regions. In another embodiment, a surface-emitting laser structure may include an active region between a first semiconductor region of a first conductivity type coupled to a first contact, and a second As semiconductor region of opposite conductivity type coupled to a second contact. A third electrical contact is dielectrically spaced from the second semiconductor region.

Abstract: A highly reliable optical add/drop device is described. The optical add/drop device has an external tube and a ring, wherein the external tube and the ring are made of metallic material. A WDM filter is fixed in the ring. The ring is inserted in the external tube at the middle portion and fixed therein by soft solder technique. A single fiber collimator and a dual fiber collimator are respectively coupled with the opposite surfaces of the filter, and aligned in the external tube. Additionally, the single and dual fiber collimators are also fixed therein by soft solder technique, as two metal tubes respectively hold the single and dual fiber collimators. In the invention, the WDM filter is rigidly fixed to avoid tilting during temperature variation. Moreover, the invention provides an optical add/drop device with low insertion loss and reflection loss.

Abstract: A vertical-external-cavity surface-emitting laser (VECSEL) is formed by providing a monolithic portion having a first laser cavity mirror and an active region disposed on the first mirror. The cavity is completed with a second laser cavity mirror, such as a DBR, deposited onto the light-receiving end of an optical device, such as an optical fiber. The DBR-on-fiber-end is mounted with respect to the active region to complete the laser cavity and to provide automatic coupling of the output laser light into the fiber.

Abstract: A camera for measuring the distance to an object is combined with a laser range measuring device by using a beam splitting device so as to simultaneously take the image of the object and measure the distance between the camera and the object. Using the focal length of the lens, the width and height of the image on the image detector, and the distance between the camera and the object, it is then possible to compute the width and height of the object according to the geometrical optics. By means of obtaining the speed of the image moving on the image detector, the camera of the invention further computes the speed of the object which is projected on a plane perpendicular to the optical axis of the lens.

Abstract: An embodiment of a radiation detector includes a semiconductor-based blocking structure interposed between the detector's absorption region and at least one of its contact structures. The blocking structure is adapted to prevent minority carriers generated within the adjacent contact structure from reaching the absorption region, and may also prevent minority carriers generated within the absorption region near the contact structure from entering the contact structure. Majority carriers, on the other hand, may be substantially unimpeded by the blocking structure in moving from the absorption region to the contact structure. In an embodiment, the blocking structure has a higher effective energy gap than its adjacent contact structure and than the absorption region. The interface between the blocking structure and the absorption region may be graded, so that the effective energy gap decreases gradually between the blocking structure and the absorption region.

Abstract: A thermal responsive, water soluble polymer. The polymer comprises the co-polymerization product of: (a) 5˜95 wt % of N-isopropyl acrylamide (NIP); (b) 0.1˜80 wt % of 1-vinyl-2-pyrrolidinone (VPD); and optionally, (c) 0.1˜30 wt % of acrylic acid (AA). As the proportion of component (b) VPD increases, the Lower Critical Solution Temperature (LCST) and water solubility of the polymer increases. On the other hand, as the proportion of component (c) AA increases, the Lower Critical Solution Temperature (LCST) decreases and the COOH reactive groups increases, which impart high reactivity to the copolymer. By adjusting the proportion of the monomers, a broad range of LCST can be manipulated from about 20 to 80° C.

Abstract: An embodiment of a surface-emitting laser structure includes a first semiconductor region of a first conductivity type coupled to a first contact and a second semiconductor region of the same conductivity type coupled to a second contact. A third semiconductor region of the opposite conductivity type is coupled to a third contact and interposed between the first and second semiconductor regions. An active region is interposed between the first and third regions. In a further embodiment, the laser structure may include a variable refractive index structure interposed between the second and third semiconductor regions. In another embodiment, a surface-emitting laser structure may include an active region between a first semiconductor region of a first conductivity type coupled to a first contact, and a second semiconductor region of opposite conductivity type coupled to a second contact. A third electrical contact is dielectrically spaced from the second semiconductor region.

Abstract: A multiple reflectivity band reflector (MRBR) includes a stack of dielectric layers, arranged so that the reflector has a reflectivity profile comprising a plurality of reflectivity bands, e.g. at least first and second wavelength bands with reflectivity above a lasing threshold reflectivity, separated by a third wavelength band between the first and second wavelength bands having reflectivity below the lasing threshold reflectivity. A laser having at least a first mirror and an MRBR as the second mirror has a laser cavity, at least a portion of which is defined by the first mirror and the MRBR. An active region located within the laser cavity contains a material that is capable of stimulated emission at one or more wavelengths in the first and second wavelength bands. The gain spectrum of the laser is adjusted to select one of the first and second wavelength bands, thereby providing for lasing at a wavelength within the selected wavelength band. The laser may be, e.g.

Abstract: A vertical-external-cavity surface-emitting laser (VECSEL) is formed by providing a monolithic portion having a first laser cavity mirror and an active region disposed on the first mirror. The cavity is completed with a second laser cavity mirror, such as a DBR, deposited onto the light-receiving end of an optical device, such as an optical fiber. The DBR-on-fiber-end is mounted with respect to the active region to complete the laser cavity and to provide automatic coupling of the output laser light into the fiber.

Abstract: A metal bonded vertical-cavity surface-emitting laser (VCSEL) structure with a bottom dielectric distributed Bragg reflector (DBR) mirror, and method for fabricating the VCSEL structure. The VCSEL structure consists a metal bonding layer disposed on a submount at a bottom side of the metal bonding layer; a bottom cavity mirror comprising a bottom dielectric distributed Bragg reflector (DBR) disposed within the metal bonding layer, the bottom dielectric DBR having a reflectance band including the lasing wavelength; a bottom current-spreading layer disposed on said bottom dielectric DBR and on a substantially flat, annular top surface of said metal bonding layer; a semiconductor active region disposed on the bottom current-spreading layer, said active region capable of stimulated emission at the lasing wavelength; and a top cavity mirror disposed above the active region and having a reflectance band including the lasing wavelength.

Abstract: A multiple reflectivity band reflector (MRBR) includes a stack of dielectric layers, arranged so that the reflector has a reflectivity profile comprising a plurality of reflectivity bands, e.g. at least first and second wavelength bands with reflectivity above a lasing threshold reflectivity, separated by a third wavelength band between the first and second wavelength bands having reflectivity below the lasing threshold reflectivity. A laser having at least a first mirror and an MRBR as the second mirror has a laser cavity, at least a portion of which is defined by the first mirror and the MRBR. An active region located within the laser cavity contains a material that is capable of stimulated emission at one or more wavelengths in the first and second wavelength bands. The gain spectrum of the laser is adjusted to select one of the first and second wavelength bands, thereby providing for lasing at a wavelength within the selected wavelength band. The laser may be, e.g.

Abstract: A laser apparatus has a first mirror, a second mirror, at least a portion of which is defined by the first and second mirrors. The laser has an active region located in the laser cavity, which is capable of stimulated emission at one or more wavelengths of light. The second mirror comprises a plurality of dielectric layers arranged in parallel and having a reflectivity band with a peak reflectivity at a peak wavelength, said reflectivity band having a width of less than 1 nm at a reflectivity of 3% less than the peak reflectivity. The laser apparatus may be a tunable laser apparatus in which the peak wavelength of the reflectivity band is adjusted, thereby adjusting the lasing wavelength of the laser. The reflectivity band may be a lasing threshold reflectivity band over which the reflectivity of the second mirror is greater than a lasing threshold reflectivity which is sufficient to permit lasing.

Abstract: A monitored laser system has a laser having a first mirror; an exit mirror, at least a portion of a laser cavity defined by the first mirror and the exit mirror; and an active region located in the laser cavity, the active region containing a material that is capable of stimulated emission at one or more wavelengths of laser light within a tuning range of the laser. A multiple reflectivity band reflector (MRBR) is coupled to at least a portion of laser light emitted from the laser and transmits filtered laser light. The MRBR has a plurality of layers of material arranged in parallel such that the reflector has a plurality of reflectivity peaks within the tuning range, each reflectivity peak separated from neighboring reflectivity peak by a reflectivity trough having a trough minimum, said reflectivity peaks characterized by a peak profile and said trough minima between said reflectivity peaks characterized by a trough profile.

Abstract: A zigzag waveguide device-based apparatus and method for achieving or maintaining wavelength lock for a tunable laser designed to generate light at a selected one of a plurality of target wavelengths. The apparatus has a reflectively coupled zigzag waveguide device for receiving a portion of light output by the tunable laser, the zigzag waveguide device having a plurality of filters, each having a passband centered at a respective one of the plurality of target wavelengths, whereby said zigzag waveguide device produces a plurality of filtered light outputs. A plurality of photosensors is provided, one for each of said plurality of filters, each said filter positioned to receive a respective one of the plurality of filtered light outputs, each said filter producing a filter output signal related to the intensity of said portion of light in the passband of the corresponding filter.

Abstract: A high precision laser range finder comprises an APC loop for eliminating a timing jitter problem due to different reflections on a target. The APC loop comprises a laser receiver, a peak holding circuit, an integrator and a high voltage generator. The peak holding circuit is connected with the laser receiver for detecting a signal strength outputted from the laser receiver. The high voltage generator provides the laser driver and laser receiver with voltage so as to control the strength of the emitted laser pulse signal of the laser driver and the gain of the avalanche photo-detector. The integrator is used to eliminate the steady error in the APC loop. Furthermore, a time to amplitude converting circuit comprises an AJD converter for obtaining a distance data and then filtering in a microprocessor to increase the measurement accuracy.

Abstract: This invention provides cycloaliphatic polyimide having the following formula (I): wherein 1 and n are integers from 4 to 7; m is an integer from 0 to 2; p is an integer from 1 to 8; polycyclic aliphatic compound R reprents C1-8 cycloalkyl, cycloalkenyl, cycloalkynyl, norbornenyl, decalinyl, adamantanyl, or cubanyl. That cycloaliphatic polyimide can be a through transparent film, their thermal stability is over 430° C. and dielectric constant is about 2.7.