Ortel Corporation

Israel Ury

Henry A Blauvelt

Sze-Keung Kwong

Harold A Zarem

Xian L Yeh

Nadav Bar-Chaim

Kam Y Lau

Amnon Yariv

Howard L Loboda

David B Huff

Ching-Jong Lii

Ronald S Moeller

Henery A Blauvelt

A fiber optic RF signal distribution system has a plurality of antenna stations, each station including an RF antenna. A central RF signal distribution hub receives and transmits signals external to the system. A pair of optical fibers connects each antenna station directly to the distribution hub with the connections being in a star configuration. A connectorized laser module permits direct coupling of a distributed feedback semiconductor laser to the end of each optical fiber without an intervening connector. The module accepts an APC connector with the angled end of its optical fiber in an aperture plane in a connector housing. A distributed feedback laser is mounted in the connector housing with a lens for illuminating the aperture plane and hence, the end of the fiber at an acute angle to the axis of the fiber. Furthermore, the illumination is defocused at the aperture plane for loose optical coupling to the fiber and minimized reflection to the DFB laser.

Fiber optic connector housing

Low cost optical fiber RF signal distribution system

A fault tolerant fiber optic system has a plurality of lasers modulated by the same signal source. The signals from the lasers are conveyed to an optical coupler by single mode optical fibers. The signals from all of the lasers are mixed in the optical coupler, producing an output signal which is an average of the input signals from the lasers. The optical coupler has a plurality of output single mode fibers which can transmit the averaged signal to a number of optical receivers. By optically combining the signals in phase with each other, the failure of any laser decreases signal strength, but does not disable the system. Surprisingly, the averaging also has the capability of improving the carrier to noise and carrier to distortion ratios for the system, since noise and distortion from the lasers are not correlated and are diminished by a factor of N where N is the number of lasers.

Fault tolerant fiber optic transmission system

This optical receiver is capable of receiving broadband R-F modulated signals transmitted over fiber-optic cable. The receiver comprises a photodiode impedance matched to the input of an low noise, low distortion amplifier by an impedance matching transformer. A passive tuning network is placed between the photodiode and the transformer to improve the high frequency performance of the receiver. Distortion of the optical receiver is further reduced by cancelling even power distortion products from out of phase signals generated by the photodiode.

Broadband optical receiver with passiner tuning network

A small module for converting an electrical signal to a modulated light signal on an optical fiber comprises a housing, a laser mounted on a laser substrate within the housing, a GRIN lens and an optical isolator downstream from the laser, and a precision capillary for holding an optical fiber downstream from the optical isolator. The relative positions of the laser, lens, optical isolator and fiber are adjusted to maximize light output through the fiber. The optical fiber is sealed to the housing at one point and is free to move axially in the capillary for minimizing mechanical stress on the fiber.

Laser module with compliant optical fiber coupling

A buried heterostructure window device has an elongated layer of gain medium surrounded by a lower index of refraction medium for guiding light along the length of the gain medium. A window and an antireflective layer are deposited on the output end of the gain layer to minimize reflections. A portion of the gain medium nearer the output end of the device is electrically pumped, leaving an unpumped end of the gain medium remote from the output end. The unpumped portion of the gain medium absorbs light travelling along the length of the gain medium. This inhibits reflection from the end of the gain medium remote from the output end. When the device is pumped with a moderate power level, strong superluminescent output is obtained. When the device is pumped well above the lasing threshold by reason of 'burning through' the unpumped absorbing portion of the gain medium, a single mode laser is obtained with side band power at least 20 db below the power of the principal oscillation mode. 'Burning through' the unpumped absorbing portion can be inhibited by extracting current carriers from that portion of the medium.

Superluminescent diode and single mode laser

Coherent coupling of a plurality of reflection type optical gain elements with a seeding laser is provided by illuminating the optical gain elements with fanned laser light scattered from a photorefractive medium. The reflection type optical gain elements have an anti-reflective end nearer the photorefractive medium and a reflective opposite end. The optical gain elements also illuminate the photorefractive medium. The resultant amplified and coherent light beam has its wavefront cleaned up with a photorefractive oscillator to provide a diffraction limited or nearly diffraction limited beam.

Coherent coupling of optical gain elements

A small module contains means for converting an electrical signal to a correspondingly modulated light signal on an optical fiber. Frequency of the signal can range from D.C up to many gigahertz. A semiconductor laser diode is mounted on a high thermal conductivity substrate on a thermoelectric cooler for controlling laser temperature. The optical fiber output is soldered to the laser substrate with an end in alignment with the laser junction. A laser bias circuit is on a connection substrate adjacent to the laser substrate. A connection substrate also includes a deposited signal lead line connected to the bias circuit by an impedance matching means. Electrical signals from the pin of an external coaxial connector are coupled to the lead line. The laser bias circuit and signal lead line are electrically connected to the laser diode by wires between the connection substrate and the laser substrate. A photodiode in the module in the light path from the laser provides a control signal.

High speed fiberoptic laser module

A buried heterostructure window device has an elongated layer of gain medium surrounded by a lower index of refraction medium of guiding light along the length of the gain medium. A window and an antireflective layer are deposited on the output end of the gain layer to minimize reflections. A portion of the gain medium nearer the output end of the device is electrically pumped, leaving an unpumped end of the gain medium remote from the output end. The unpumped portion of the gain medium absorbs light travelling along the length of the gain medium. This inhibits reflection from the end of the gain medium remote from the output end. When the device is pumped with a moderate power level, strong superluminescent output is obtained. When the device is pumped well above the lasing threshold by reason of 'burning through' the unpumped absorbing portion of the gain medium, a single mode laser is obtained with side band power at least 20 db below the power of the principal oscillation mode. 'Burning through' the unpumped absorbing portion can be inhibited by extracting current carriers from that portion of the medium.

Growing community of inventors

Los Angeles, CA, United States of America

Israel Ury