Abstract: A low threshold distributed feedback (DFB) laser is constructed for improved performance at subzero temperatures. A loss grating is employed to enhance the probability that lasing occurs near the short wavelength side of the stopband and to counteract the effect of negative gain tilt that occurs when DFB lasers are positively detuned. A method of making DFB lasers from wafers with improved yield for low temperature side mode suppression ratio (SMSR) is also disclosed.

Abstract: An improved semiconductor laser (distributed feedback or Bragg reflector laser) is disclosed, having reducing wavelength chirping. In a laser having a substrate, an optical waveguide layer disposed on the substrate with a grating region, and a cladding region disposed on the optical waveguide layer, an isolation region is positioned in at least one of the substrate, optical waveguide layer, and cladding layer. The isolation region is comprised of a material adapted to increase the resistivity of the one or more layers in which it is placed to reduce electrical cross-talk and wavelength chirping. Preferably, the isolation region is positioned in at least the cladding layer, which the inventors have found is the greatest contributor of cross-talk and wavelength chirping.

Abstract: A low threshold distributed feedback (DFB) laser is constructed for improved performance at subzero temperatures. A loss grating is employed to enhance the probability that lasing occurs near the short wavelength side of the stopband and to counteract the effect of negative gain tilt that occurs when DFB lasers are positively detuned. A method of making DFB lasers from wafers with improved yield for low temperature side mode suppression ratio (SMSR) is also disclosed.

Abstract: A low threshold distributed feedback (DFB) laser is constructed for improved performance at subzero temperatures. A loss grating is employed to enhance the probability that lasing occurs near the short wavelength side of the stopband and to counteract the effect of negative gain tilt that occurs when DFB lasers are positively detuned. A method of making DFB lasers from wafers with improved yield for low temperature side mode suppression ratio (SMSR) is also disclosed.

Abstract: A semiconductor device is provided with at least two photodetectors and an interposed etalon. Signals from the photodetectors may be compared to generate a control signal. The control signal may be used for wavelength control and/or stabilization and for other purposes. According to a preferred embodiment, the etalon is formed of at least two distributed Bragg reflectors. The etalon provides high discrimination power. In addition, the etalon has a periodic discrimination function that may be matched to the periodic channels of a dense wavelength division multiplexing system. According to one aspect of the invention, electrical current may be applied to selected layers of the device to tune and/or shift the response of the device. If desired, the invention may be incorporated into a waveguide structure, such as an optical fiber. The present invention also relates to a wafer fusion technique for making integrated devices.

Abstract: The invention is a semiconductor laser including a grating which is formed by regions of high impurity concentration surrounded by material having a lesser impurity concentration. The use of variations in doping concentration rather than different materials to provide reflection in the grating should simplify device fabrication.

Abstract: A compact and cost-effective wavelength meter and photodetector (10) that can measure simultaneously both wavelength and intensity has two back-to-back photodiodes (12 and 14) with a wavelength dependent distributed Bragg reflector (DBR) (28) positioned in-between. The wavelength resolution of this device is 1 nm or less. Easy design and fabrication of the device provides for reliable and cost-effective manufacturing. Applications include instrumentation and wavelength-division-multiplexing (WDM) in optical communication systems.