摘要:
A waveguide DBR laser or waveguide DBR laser array may be comprised of a semiconductor gain element, or a series of semiconductor gain elements, in combination with a waveguide grating functioning as a resonant cavity end reflector for lasing operation comprising either an optical fiber having a fiber grating (fiber DBR laser) or a planar waveguide (planar waveguide DBR laser). The gain element may be comprised of a laser diode which has high efficient AR coating on its front facet so that it functions as a modulated gain element in a resonant cavity established between its rear HR facet and the grating formed in the external waveguide. Disclosed are ways to form this resonant cavity so that gain element modulation rates can be carried out in excess of 2 Gb/sec with suppression of longitudinal mode hops and/or with trimming to compensate for wavelength changes, rendering the waveguide DBR laser or waveguide DBR laser array highly suitable for WDM transmitter, dense WDM transmission systems and other communications applications.
摘要:
An optical connection module attaches an active or passive optical component to a substrate and aligns the optical component with a first laser. The optical connection module includes a fiber submount that is attached to the substrate and that includes a thermally insulating material having a thickness greater than 20 micrometers. The optical component is soldered to the fiber submount using heat from a second laser. A laser submount is attached to the substrate. The first laser is attached to the laser submount. A fiber bonding pad is located between the thermally insulating material and the optical component. The thermally insulating material and the fiber bonding pad promote lateral heat transfer and limit vertical heat transfer to the substrate during soldering. The thermally insulating material can be integrally formed in the substrate by flame hydrolysis or by anodic bonding.
摘要:
High power semiconductor lasers for pumping fiber devices, such as fiber amplifiers and fiber lasers, include an optical gain region disposed between a rear end and the output end, the width of the optical gain region being greater at the output end than at the rear end. The optical gain region may include a single mode channel region coupled to a flared amplifier region. The light output from the laser is coupled via a lens system into a fiber for propagating to the fiber device to be pumped. Light is fedback into the laser, for example from a fiber Bragg grating, to induce the laser to operate in coherence collapse. The broad bandwidth output associated with coherence collapse permits the laser to deliver high optical powers into the fiber without the onset of stimulated Billion scattering. Fiber grating feedback improves the quality of the beam output by the laser, thus enhancing coupling efficiency into the fiber. The pump laser may be used to pump multiple fiber devices. Multiple pump lasers may be combined together.
摘要:
An optical amplifier with a flattened wideband response is obtained by coupling counter-propagating pumping energy into an optical waveguide to cause Raman amplification in the optical waveguide, and by reflecting an amplified signal received from the optical waveguide into an output waveguide using a reflector having a spectral characteristic that is complementary to the spectral gain characteristic of the Raman amplification.
摘要:
An optical amplifier with a flattened wideband response is obtained by coupling counter-propagating pumping energy into an optical waveguide to cause Raman amplification in the optical waveguide, and by reflecting an amplified signal received from the optical waveguide into an output waveguide using a reflector having a spectral characteristic that is complementary to the spectral gain characteristic of the Raman amplification.
摘要:
Apparatus for providing a laser source optically coupled to an optical waveguide, such as an optical fiber, having a reflective grating positioned from the output facet of the laser source a distance equal to or greater than the coherence length of the laser source providing a portion of reflective feedback into the laser source optical cavity to maintain wavelength operation of the laser source in spite of changes in the laser operating temperature or drive current based upon coherence collapse in the laser operation. In cases where the fiber grating is positioned in the fiber within the coherence length of the laser source, intermittent coherence collapse, as opposed to continuous coherence collapse, is unavoidable. In cases where such a laser source is a pumping source for a solid state gain medium, such as an optical amplifier or laser having an active gain element, e.g., an Er doped amplifier, undesirable perturbations in the laser source output are present which have a deleterious effect on the operation of the solid state gain medium. The effect of these undesirable perturbations are substantially removed by a small, continuous variation or dither in the driving current of the laser source having a rate of variation that exceeds the active gain element excited state lifetime thereby controlling the switching of the laser source operation between states of coherency and coherence collapse. As a result, the effects of laser source perturbations are avoided so as not to have an effect on the operation of the coupled solid state gain medium so that its gain stability is improved. Various embodiments of dither circuits are disclosed. In addition, polarization-maintaining behavior is induced in optical waveguides to further improve laser source stability.
摘要:
A pump source for rare earth and Raman amplifiers or for distributed amplification uses two or more light sources to generate two source beams that are combined by a beam combiner to form the output pump beam. In accordance with one embodiment, the light sources are a diode laser array having be two or more monolithic laser stripes providing dual output beams having substantially the same polarization, such as the TE mode. One of the polarized due outputs is rotated 90° and both beams are applied to a birefringent crystal that combines the beams for insertion into an optical fiber or into a rare earth doped fiber or into a fiber capable of Raman amplification via SRS. The power output of each polarization in the combined beam can be measured and used to drive a feedback circuit that controls the current provided to each diode in order to maintain the power in the two polarization components of the output beam equal.
摘要:
Consistent with the present disclosure, optical devices are provided along different optical paths in a photonic integrated circuit (PIC). The optical components have different optical losses associated therewith so that optical signals propagating in the optical paths have desired power levels, which may be uniform, for example.
摘要:
System, devices and methods are described that provide an integrated optical decombiner or optical combiner having both unamplified paths and amplified paths on which power monitoring and control may be located. A preferred multiplexing/demultiplexing optical path through the combiner/decombiner and a corresponding waveguide output/input is identified and optically coupled to a piece of fiber. Temperature control may be provided to tune an arrayed waveguide grating within the combiner/decombiner and minimize wavelength drift therein. Integrated power monitoring may be employed on one or more of the amplified waveguide paths to ensure that a preferred power level or range is maintained on an optical signal.
摘要:
Disclosed are apparatus and methods of reducing insertion loss, passivation, planarization and in-wafer testing of integrated optical components and in-wafer chips in photonic integrated circuits (PICs).