International Business Machines Corporation

Leland Stanford Junior University

Tellabs Operations, Inc.

Lightwave Logic Inc.

Karen Liu

Franklin F Tong

Weyl-Kuo Wang

Herbert J Shaw

Paul Eliot Green, Jr

William Eric Hall

Rajiv R Ramaswami

Michel J Digonnet

Byoung Y Kim

Frank J Janniello

Jeff Kenneth Kravitz

Chaoyu Yue

Michael M Choy

Michael S Lebby

Wayne V Sorin

Chung-Sheng Li

Frederick J Leonberger

Harold S Stone

John J Fling

Kenneth A Fesler

Stuart Douglas Brorson

A thin film polymer device including a waveguide core surrounded by dielectric material positioned on a platform. The core has a passive input portion and a passive output portion joined by a necked down active portion. A layer of EO polymer material positioned on the dielectric material overlying the active portion of the core and the core, the EO polymer, and the dielectric material all having refractive indices with the refractive index of the EO polymer being higher than the refractive index of the dielectric material. Light progressing through the core from the passive input portion to the passive output portion transitions to the layer of EO polymer material as it enters the necked down active portion and transitions back to the core as it leaves the necked down active portion.

TFP optical transition device and method

A method and apparatus for constructing an optical wavelength-routing network in which each network node is a dynamic add-drop multiplexer (OADM) with minimized spectral filtering effect on pass-through channels and survivability upon power failure. By using cascaded tunable reflection filters as the building blocks, strictly add-drop non-blocking OADMs for single input/output fibers, double input/output fibers, and 3 input/output fibers can be constructed for application to unidirectional and bidirectional ring networks and mesh networks of arbitrary degree. Methods and apparatus for minimizing various types of out-of-band and in-band crosstalk occurring within the dynamic OADMs are also described.

Dynamic optical add-drop multiplexers and wavelength-routing networks with improved survivability and minimized spectral filtering

Dynamic optical add-drop multiplexers and wavelength-routing networks

A method and apparatus for constructing a modular and easily upgradable optical network node using the technique of wavelength-division multiplexing (WDM). According to the present invention, a WDM point-to-point link end node can be modularly upgraded in the number of wavelength channels or upgraded to a ring network node; both without requiring equipment internal rewiring.

Upgradable modular wavelength division multiplexer

A wavelength division multiplexer (WDM) unit (12) includes a plurality of Input/Output cards (IOCs 14). Each IOC is bidirectionally coupled to I/O specific media (fiber or copper) and to two coaxial cables. Also bidirectionally coupled to the coaxial cables are a plurality of Laser/Receiver Cards (LRC 20). The interface between the IOCs and the LRCs is an Emitter Coupled Logic (ECL) electrical interface that is conveyed over the coaxial cables. Each LRC is bidirectionally coupled by two single mode fibers to an optical multiplexer and demultiplexer, embodied within a grating (24). An input/output port of the grating is coupled to a fiber link (28) that enables bidirectional, full duplex data communications with a second WDM. Each WDM also includes a Diagnostic Processor Card (DPC 28) that receives status signals from the IOCs and LRCs, that forwards the status signals on to an external processor, and which generates control information for the IOCs and LRCs. Each IOC is associated with one of a plurality of communications channels and includes an I/O specific media connector (30) that is coupled to an appropriate transmitter (Tx) and receiver (Rx). The I/O specific media connector, Tx and Rx are constructed and operated in accordance with the specific data stream type that is input to and output from the associated channel of the WDM. By example, a first data stream may be conveyed through an optical (fiber) conductor in accordance with an ESCON protocol at 200 Mb/s, and a second data stream may be conveyed through an electrical (copper) conductor in accordance with an ECL non-specific protocol at up to 622 MB/s.

Optical wavelength division multiplexer for coupling to data sources and

This invention provides methods and apparatus for achieving wavelength sorting multiplexer/demultiplexer and its application to the implementation of planarized dynamic wavelength routing. Using integrated arrayed-waveguide gratings, sorting can be achieved by two configurations. In the first configuration channel wavelengths are properly selected and launched into prearranged input waveguides of an arrayed-waveguide grating such that channels at the same wavelength and from all inputs will be demultiplexed and routed to adjacent outputs. Operated in the reverse direction, the same device becomes a sorting multiplexer. The second configuration achieves wavelength sorting by using the cascade of multiple arrayed-waveguide gratings and can also be operated as a demultiplexer or a multiplexer. Combined with space switches, the wavelength sorting multi/demultiplexer are utilized to implement the planarized channel-selective dynamic wavelength router. The function of wavelength sorting eliminates on-chip waveguide crossings and therefore reduces losses and crosstalks. The sorting demultiplexer and multiplexer can further be implemented with a single arrayed-waveguide grating.

Wavelength sorter and its application to planarized dynamic wavelength

A wavelength division multiplexer (WDM) unit (12) includes a plurality of Input/Output cards (IOCs 14). Each IOC is bidirectionally coupled to I/O specific media (fiber or copper) and to two coaxial cables. Also bidirectionally coupled to the coaxial cables are a plurality of Laser/Receiver Cards (LRC 20). The interface between the IOCs and the LRCs is an Emitter Coupled Logic (ECL) electrical interface that is conveyed over the coaxial cables. Each LRC is bidirectionally coupled by two single mode fibers to an optical multiplexer and demultiplexer, embodied within a grating (24). An input/output port of the grating is coupled to a fiber link (28) that enables bidirectional, full duplex data communications with a second WDM. Each WDM also includes a Diagnostic Processor Card (DPC 28) that receives status signals from the IOCs and LRCs, that forwards the status signals on to an external processor, and which generates control information for the IOCs and LRCs.

Optical wavelength division multiplexer for high speed,

The invention is a system and method for improving the signal-to-noise ratio of an electrical data signal transmitted between two electronic modules. An electrical data signal from a first module is amplified by an electrical amplifier to produce an amplified electrical data signal. The electrical amplifier is supplied by a power distribution network. The amplified electrical data signal has a power level sufficiently low such that the electrical amplifier does not cause significant disturbances in the power distribution network so that a plurality of the electrical amplifiers can be proximately located and operated concurrently without significant noise coupling occurring between the electrical amplifiers through the power distribution network. The electrical data signal is then converted to an optical data signal for transmission to a second module. The optical data signal is transmitted to the second module through an optical path where it is optically amplified. The amplified optical data signal is then received at the second module and detected to produce an electrical signal which has a substantially improved signal-to-noise ratio.

Interconnections having improved signal-to-noise ratio

This invention describes a double-pass optical filter having a pair of reflective surfaces with a pair of optical media of different indices of refraction inserted between the surfaces. Light is then passed through the surfaces and through each of the optical media to obtain selected frequencies. This invention also includes a means for varying the distance between the reflective surfaces so as to tune the filer over a continuous range of frequencies. The continuous simultaneous turning of two resonant can be achieved by merely displacing one reflective surface relative to another.

Double-pass tunable fabry-perot optical filter

An optical fiber laser includes a single-mode optical fiber doped with a lasing material such as Neodymium. The optical fiber is pumped with a pump optical signal having a pump wavelength selected to cause spontaneous emission of an optical signal at a second wavelength different from the pump wavelength. The optical fiber is formed into a laser cavity such as by including a suitable reflector at each of the two ends of a suitable length of the optical fiber so that the emitted optical signal oscillates therein. One of the reflectors has a reflectivity at the wavelength of the emitted light so that most (e.g., approximately 95%) of the emitted light is reflected back into the laser cavity and a smaller portion (e.g, approximately 5%) is transmitted through the mirror as a laser output signal. Alternatively, the optical fiber can be formed into a ring laser structure using an optical coupler that couples a substantial portion (e.g., approximately 95%) of the emitted light back into the ring for recirculation therein and provides a smaller portion of the emitted light (e.g., approximately 5%) as a laser output signal. The wavelength of the pump optical signal is selected to be outside the pump variable tuning range of the Neodymium-doped optical fiber (i.e., the range of pump wavelengths which stimulate emitted wavelengths having a average wavelengths with a generally one-to-one correspondence to the pump wavelength). Pumping with a pump signal outside the pump variable tuning ranges causes the emitted light to have a broad spectral envelope of longitudinal modes having emission wavelengths corresponding to substantially all the pump variable tuning range. Thus, by pumping the optical fiber with a single pump wavelength, a broadband laser output signal is generated.

Broadband optical fiber laser

A superfluorescent broadband fiber laser source comprises a fiber doped with laser material coupled to a multiplexing coupler. In the preferred embodiment, a source of pumping illumination provides pumping light to the doped fiber, and the coupler is adjusted to have a 0% coupling efficiency at the wavelength of the source. The pumping light is sufficiently intense to produce amplified spontaneous emission within the doped fiber, and gives rise to a forward signal and a backward signal. One of the superfluorescent signals is reflected back to the doped fiber by a reflector cemented to one end of the doped fiber or to one end of another fiber through the coupling function of the coupler. The coupler is adjusted to provide complete coupling at the frequency of the lasing light. The temperature dependence of the coupler can be selected to reduce or cancel the temperature dependence of the superfluorescent signal. Other arrangements utilizing the multiplexing properties of the coupler are also described. An all-fiber reflector can also be used.

Superfluorescent broadband fiber laser source

An apparatus selectively transmits light in one of two orthogonal polarizations in an optical fiber. The apparatus has a facing surface formed at one location on the fiber to expose the evanescent field of an optical signal in the fiber. A nematic liquid crystal is placed in contact with the facing surface so that it is in communication with the evanescent field of the optical signal. The nematic crystals have a first orientation state which presents a first refractive index to light traveling in one polarization and a second refractive index to light traveling in the other polarization. The light traveling in one polarization is well guided while the light traveling in the other polarization is radiated at the facing surface. Thus, only light of one polarization continues to propagate through the fiber. The nematic crystals have a second orientation state in which the relative refractive indices for the two polarizations of light are changed so that the polarization which was originally well guided is radiated at the facing surface and the polarization which was originally radiated is well guided. The change in the orientation states of the nematic crystals is accomplished by applying an electric field between two electrodes so that the nematic crystals align themselves with the electric field.

Growing community of inventors

Montclair, NJ, United States of America

Karen Liu