Laser pump module with reduced tracking error
Granted: October 31, 2002
Application Number:
20020159489
A laser package comprises a laser diode source having a first Fabry-Perot cavity between a highly reflective back facet and low reflective front facet for providing a first light output for an optical application. A light monitor is positioned adjacent to the back facet and aligned to receive a second light output from the laser diode back facet. A pigtail fiber having a lensed fiber input end is positioned from the laser diode front facet to form an optical coupling region and is…
Lensed optical fiber
Granted: October 31, 2002
Application Number:
20020159693
A microlens on the end of an optical fiber has reduced back reflections to a light source, such as a pump laser diode. In a particular embodiment, the microlens is lapped on two radii, at least one of which is offset from the center axis of the fiber, to form a point on the end of the fiber, thus reducing a surface for reflecting light back to the light source. In another embodiment, the microlens is formed with two different side surface angles to accommodate misalignment of the light…
Modified PM tap couplers
Granted: October 31, 2002
Application Number:
20020159704
A fused optical coupler has a PM and a non-PM fiber with equal clad diameters. The fibers are plaited together without applying torsional force on either fiber, fused and stretched to a degree resulting in a tap ratio not more than 10% and PER higher than about 20 dB.
Mach-Zehnder optical modulator
Granted: October 31, 2002
Application Number:
20020159128
The present invention relates to a Mach-Zehnder optical modulator having an electrode structure that is arranged to compensate for temperature induced performance degrading variations. The distances between appropriate faces of the signal electrode and a ground electrode and corresponding wave-guide arms are arranged such that there is a more balanced thermal expansion of the waveguide arms due to heating of the waveguides by the RF signals carried on the signal and ground electrodes.…
Optical aligning by eccentric laser welding
Granted: October 10, 2002
Application Number:
20020146209
Automated manufacturing in the fiber optics industry has introduced a series of new problems due to the small size of the parts being assembled and the precise optical alignments required. However, processes requiring the manual assembly of parts using glue are slowly being replaced by automated processes involving the laser welding of metallically encased optical parts. Unfortunately, almost every step in the process causes a small degree of misalignment, which may cause the device to…
Compact optical fiber coupler
Granted: October 3, 2002
Application Number:
20020141705
The inventive coupling device enables a high interconnection density of single mode optical fiber in active and passive devises used in a fiber optic telecommunication system. The coupling device comprise a micro-lens formed by terminating a single mode optical fibers with an optimized gradient index fiber, thus avoiding a significant increase in fiber diameter. The gradient index is optimized to provide a long working distance to the minimum spot size so that efficient coupling can be…
3-port optical device
Granted: August 29, 2002
Application Number:
20020118463
A thee port polarization beam splitter is disclosed which utilizes only two GRIN lenses. Two beams are split by a bireferingent crystal into two orthogonally linear polarized parallel sub-beams. The two parallel beams are redirected to converge to a single same location at an end face of the GRIN lens by a roof prism and are coupled by the same lens to two optical fibers held in a fiber tube physically coupled to the GRIN lens.
Cascaded RZ and NRZ laser modulators having RZ/NRZ phase alignment bias control
Granted: August 22, 2002
Application Number:
20020114047
An optical transmitter architecture has a return-to-zero (RZ) laser modulator coupled in cascade with a non-return-to-zero (NRZ) laser modulator. DC bias and modulation signal drive levels of the two modulators are controlled using dither-based feedback, so as to align the phase of the RZ signal with that of the NRZ data. A first method uses an RZ quadrature phase dither or an RZ hillclimber phase dither, to apply a relatively low frequency dither signal to a variable RF delay for the RZ…
Polarization beam splitter/combiner
Granted: August 15, 2002
Application Number:
20020109918
A beam splitter and/or beam combiner is disclosed which in a splitting mode of operation receives an input beam of light and splits the beam into two orthogonally polarized parallel sub-beams of light. The device uses two wedges wherein at least one is birefringent or wherein both are birefringent such as a Wallaston prism, for splitting the input beam into two sub-beams wherein at least one diverges from the other, to provide two diverging beams. Only one or two small crystals are…
Optical system for aligning a collimated beam
Granted: August 8, 2002
Application Number:
20020106153
The invention provides an optical collimator assembly having an optical fiber for transmitting a beam of light, a lens for substantially collimating a beam of light received from the optical fiber, and a light transmissive element disposed to receive a beam of light from the lens for correcting an angular deviation in the beam of light received from the lens. If desired, two wedges are used to correct an angular deviation of a beam exiting a collimator, wherein the two wedges have a…
Apparatus and method for generation of optical signals
Granted: July 18, 2002
Application Number:
20020093644
A laser system is disclosed wherein a tunable laser signal has encoded within it information related to its wavelength at any instant in time. This encoding in one example is performed by modulating the signal to contain its wavelength information. This is particularly useful in a distributed system for testing optical components, wherein at a test site, the test station must determine the wavelength of light at which a component was tested.
Variable optical attenuator device
Granted: July 11, 2002
Application Number:
20020090192
A variable optical attenuator device is provided for modulating an optical signal. The attenuator device includes a variable attenuation assembly with an electrochromic structure interposed between a first electrode and a second electrode. The electrochromic structure is configured to reversibly change its optical characteristics from a bleached off state to a colored active state under the influence of an electrical potential applied to the first and second electrodes to thereby…
Structure for reducing optical beam spacing
Granted: June 20, 2002
Application Number:
20020075576
Parallel optical beams emitted by an array of optical devices e.g. collimators are spaced by a distance that is not smaller than the diameter of the collimators etc. devices. To reduce the spacing of the beams at the point of incidence on the receiving element or device, a structure is provided having a first and a second array of reflective surfaces e.g. mirrors or prisms, the arrays defining pairs of corresponding reflective surfaces. The surfaces are arranged such that the beams…
Control system for optical cross-connect switches
Granted: June 20, 2002
Application Number:
20020076136
A control system is designed to control an optical cross-connect having a switch core defined by first and second independently movable beam deflectors capable of selectively defining an optical path between a pair of ports of the optical cross-connect. An optical element having optical power is arranged in a propagation path of light beams between the first and second beam deflectors. The control system includes a pilot light source, an optical sensor associated with each beam…
Bi-directional cross-connect
Granted: June 20, 2002
Application Number:
20020076144
Wavelength interleaving cross-connects pass a first optical signal including a first set of optical frequencies in a first direction and a second optical signal including a second set of optical frequencies in a second direction. In one embodiment, the first optical signal, when input to a first input/output (I/O) port, is routed from the first I/O port to a third I/O port. The first optical signal, when input to a fourth I/O port, is routed from the fourth port to a second I/O port. The…
Wavelength-dependent optical signal processing using an angle-to-offset module
Granted: June 20, 2002
Application Number:
20020076146
An optical device comprises a dispersion element, a reflector, and an angle-to-offset (ATO) element. The angle-to-offset (ATO) element has optical power. The dispersion element is positioned in or near a focal plane of the ATO element and adapted to separate an input wavelength division multiplexed (WDM) light beam received from an input port of the optical device into two or more channel light beams. The reflector is positioned in or near a focal plane of the ATO element and arranged to…
Miniature fabry-perot laser structure
Granted: June 13, 2002
Application Number:
20020071456
A laser structure, coupled to a LED pump, has an unguided uniform gain element having two mirrors forming a Fabry-Perot cavity. The gain element is coupled to an input waveguide and an output waveguide, wherein the output waveguide has a greater mode field diameter than the input waveguide. The output waveguide may be a TEC fiber. The structure is coupled to a LED pump.
Mach-zehnder modulator bias and driver gain control mechanism
Granted: May 23, 2002
Application Number:
20020061034
A microcontroller-based controller executes interleaved DC bias and gain control routines using monitored values of the monitored photocurrent output signal of a Mach-Zehnder laser modulator to derive a gain setting for the modulation drive signal and a bias level setting for the DC bias level, without tuning or adjustment. Subsequent to convergence of the gain and bias level settings, the control unit may repetitively interrupt and restart the DC bias and gain control routine at…
Cascadable large optical cross-connect
Granted: May 23, 2002
Application Number:
20020061157
A high capacity cross-connect in which a 3D switch core includes express paths that facilitate cascading of cross-connect blocks. A light beam propagates from an input waveguide 18 to a first MEMS mirror, which deflects the light beam to either an express optical path or a switching optical path. In the express optical path, the light beam propagates from the first MEMS mirror to a predetermined output waveguide, which is determined by the design of the switch core. In the switching…
Compact optical multiplexer/demultiplexer
Granted: May 16, 2002
Application Number:
20020057868
The invention relates to wavelength division multiplexing (WDM) and demultiplexing of optical signals using optical filters in free space. To minimize dispersion, the present invention uses relatively small angles of incidence. To avoid the need for a large package, the present invention utilizes reflective prisms to steer the reflected beams to provide a lateral shift in the beam path that ensures that the necessary space is provided between the input/output ports. Devices including a…
