Jds Fitel Inc.

Other

Jds Uniphase Corporation

Mark Farries

Gary S Duck

Yihao Cheng

Koichi Abe

Rajiv Iyer

Nigel Copner

Adam D Cohen

Stephen J Mihailov

Joseph W Ip

Jinghui Li

Paul Colbourne

Barrie P Keyworth

Timothy C Munks

Paul E Dunn

Andrew Finch

Norbert Fabricius

Jan Ingenhoff

Kenneth O Hill

A method and an apparatus are provided to demultiplex an optical signal having a plurality of channels at a predetermined channel spacing having demultiplexing means with a frequency spacing larger than the predetermined channel spacing for receiving the optical signal and for dividing the optical signal by wavelength into a plurality of wavelength streams broader than the predetermined channel spacing, time domain demultiplexing means for receiving one of the plurality of wavelength streams and for dividing the one of the plurality of wavelength streams into a plurality of time domain demultiplexed wavelength streams, and optical filtering means for demultiplexing one of the plurality of time domain demultiplexed wavelength streams into a single channel. Advantageously, splitting means are provided to split the optical signal into sub-signals before launching them into the demultiplexing means.

Method and apparatus for demultiplexing high bit rate optical signals on dense wavelength grid

A micro-optical delay element for a time-division multiplexing scheme is disclosed wherein two light beams are provided to a beam splitter/combiner (BS/C) in the absence of optical fibre. At least one beam exiting a modulator is collimated and reaches the (BS/C) unguided as a substantially collimated beam. This obviates a requirement for polarization controllers and polarization maintaining optical fiber

Micro-optic delay element for use in a time division multiplexed system

A micro-optical delay element for a polarization time-division multiplexing scheme is disclosed wherein two light beams are provided to a polarization beam splitter/combiner (PBS/C) in the absence of optical fiber. At least one beam exiting a modulator is collimated and reaches the (PBS/C) unguided as a substantially collimated beam. In this manner the polarization state of the beam is substantially unchanged. This obviates a requirement for polarization controllers.

Micro-optic delay element for use in a polarization multiplexed system

A 1&frac12;&times;2 optical switch has two GRIN lenses, each lens having two ports on its respective outward end face. The switch has a transmissive wedge-shaped switching element disposed between the GRIN lenses. When the switching element is disposed in the path between the GRIN lenses, a single connection is established between a port of the first GRIN lens and a port of the second GRIN lens, while light is prevented from coupling between the remaining ports.

1&frac12;&times;2 optical switch with a transmissive switching element

An optical switch is disclosed having 4-ports. The switch consists of a first GRIN lens having 2 ports adjacent its outwardly facing end face. A second GRIN lens is disposed to receive light from the first GRIN lens and has two ports adjacent its outer end face. In a first state, a first port from the first GRIN lens couples light with a first output port of the second GRIN lens. In a second state, a movable optical element in the form of a light transmissive wedge having a reflective surface, is disposed in the path between first and second GRIN lens, providing a connection between a port of the first GRIN lens and a second port of the second GRIN lens. In a third connect state, the reflective surface of the wedge connects a port of the first GRIN lens and an output port in the same first GRIN lens. Hence an N&times;M optical switch is disclosed.

N x M optical switch

A method of forming a grating in waveguide uses an ion exchange process to provide a waveguide region within and clad by a surrounding substrate and through an ion exchange process diffusing into the substrate an ion, such as such as Ag&plus;, that is photosensitive and that provides a refractive index difference from adjacent non-diffused regions of the substrate. After the diffusion process, the step of exposing at least some of the waveguide region to light having a suitable intensity and duration to provide a permanent index change within regions of the waveguide region to form a grating is performed.

Providing a refractive index change in an ion diffused material

The present invention relates to multi-wavelength filtering devices and more particularly to a multi-channel multiplexer/demultiplexor using at least one multi-port optical circulator and a plurality of Bragg optical fiber gratings or other wavelength selective means. Advantageously a drop or add/drop optical circuit including the combination of a Bragg grating providing a strong reflective response for substantially completely separating a single channel of a band of wavelengths from a plurality of other channels in a multi-channel signal, with a Bragg grating of lower reflective response which is capable of providing group delay compensation to lessen the effects of group delay introduced by the strong Bragg grating with isolation between the Bragg gratings provides a device for accurately and efficiently separating channels from a multiple channel signal with low loss.

Optical drop circuit having group delay compensation

An add-drop optical circuit is provided comprising: a first multiplex/demultiplexer for demultiplexing a composite optical signal having a plurality of channels, a second multiplex/demultiplexer for multiplexing a plurality of signals into a composite optical signal; waveguides disposed between the first demultiplexer and the second multiplexer/demultiplexer; and a plurality of 11/2.times.2 optical switches coupled to at least some of the waveguides for adding and dropping optical signals, the optical switches substantially preventing optical signals from propagating from an add port to drop port.

11/2.times.2 optical switch

A system and method are disclosed for demulitplexing closely spaced channels carrying optically encoded data. A composite optical signal having data channels corresponding to center wavelengths .lambda.1, .lambda.2, .lambda.3, .lambda.4, . . . .lambda.n are separated into two composite optical signals of first of which comprises data channels corresponding to center wavelengths .lambda.1, .lambda.3, . . . .lambda.n and a second which comprises data channels corresponding to center wavelengths .lambda.2, .lambda.4, . . . .lambda.n-1, wherein adjacent channels center wavelengths are separated from one another by a distance 'd'. A periodic multi-cavity Fabry-Perot etalon having a free spectral range of '2d' is coupled to a circulator for launching an input beam. The first of the two composite optical signals carrying channels 1, 3, . . . n is reflected from the input port of the etalon and the second of the of the two optical signals carrying channels 2, 4, . . . n-1 is transmitted through the etalon. After the two signals are separated, further separation can be achieved by using conventional dichroic filters.

Method and circuit for demultiplexing an optical signal

Light is coupled out of a first mono-mode optical waveguide such as an optical fiber an into another single mode waveguide through a substantially planar slab waveguide. The first mono-mode optical waveguide has a grating impressed within which has refractive index perturbations that reflect predetermined wavelengths of incident light out of a portion of a side of the optical waveguide adjacent the grating; The slab planar waveguide has an end optically coupled to the portion of the first mono-mode optical waveguide, for guiding light coupled out of the side of the waveguide, and for maintaining a uni-phase wavefront of said light by having a response that confines the light to a single mode in one dimension, and multi-mode in another dimension and allows at least a portion of the light to converge.

Wavelength selective fiber to fiber optical tap

An optical device simultaneously provides a multiplexing and demultiplexing function and combines dichroic WDM filter technology with Bragg grating filter technology. A plurality of adjacent sequential ports of a multi-port optical circulator serve as a vehicle for launching and receiving a multi-wavelength optical signal to be separated by the Bragg and dichroic filters. Other adjacent sequential ports having similar filters tuned to different wavelengths provide paths for combining the other wavelengths of light into a single signal. Conveniently a single circulating port serves as the input/output port of the device. The configuration can be applied an optical waveguide structure and, or more particularly to an optical fiber structure. Furthermore this configuration can combine multiplexing/demultiplexing function with a dispersion compensation function by adding a group of fiber Bragg gratings to a port of a circulator.

Hybrid bi-directional wavelength division multiplexing device

A device for coupling out of or into a transmission system which carries light signals is provided. A first optical fiber having a Bragg grating therein has its cladding optically coupled to a second optical fiber having a Bragg grating therein so as to allow at least a predetermined wavelength of light incident upon the first Bragg grating to be forward coupled from the core to the cladding and then to the core region of the second optical waveguide via the second Bragg grating.

In-line grating device for forward coupling light

A hybrid filter includes a dichroic interference WDM filter closely coupled with a Bragg grating. Preferably the Bragg grating is housed within a sleeve having an end face that is directly coupled with an end face lens of the WDM interference filter. The entire filter can be placed within a single housing and temperature controlled. Etalon effects are lessened by placing the Bragg grating as close as possible to the WDM filter. Multiple hybrid filters of this type optically coupled to an optical circulator provided multi-channel demultiplexing.

Hybrid optical filtering circuit

A device for distributing an optical signal has an optical waveguide with a plurality of gratings disposed in series therein, the gratings having a predetermined reflectivity response within a specific wavelength range; an optical circulator having at least three ports, one of the ports serving as an input port for receiving the optical signal, and another port for removing at least a part of the optical signal reflected from one of the gratings; and control means for individually controlling at least some of the gratings to effect a change of the wavelength range of the reflectivity response of the gratings. The change may be a shift, an expansion or a compression of the range. The device can function as a signal distributor (router), an equalizer or a demultiplexer. The reflectivity response is preferably a sloped response.

Variable-attenuation tunable optical router

An attenuator capable of controllably attenuating at least two wavelengths of light is configured to have an optical waveguide section having at least two Bragg gratings disposed therein in series. The Bragg gratings have a sloped reflectivity response within a predetermined wavelength range. The sloped response is a function of refractive index variations within each of the grating elements. By compressing or expanding at least one of the gratings, the periodicity is modified so as to shift its central wavelength within a predetermined wavelength range.

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Nepean, Canada

Mark Farries