Abstract:
A reconfigurable optical add/drop multiplexer (ROADM) includes a first optical dynamic gain equalization filter (DGEF) having a first input for receiving an initial wavelength division multiplexed (WDM) signal, a first output for sending a phase shifted WDM signal, and a second output connected to a demultiplexer for demultiplexing a WDM drop signal thereby producing a plurality of drop channels. A second DGEF having a first input for receiving the phase shifted WDM signal, a second input connected to a multiplexer, for multiplexing a plurality of add channels to produce thereby a wavelength division multiplexed (WDM) add signal, and an output for sending a second adjusted WDM signal. The ROADM allows for the channels from the initial WDM signal to be dropped, added and equalized.
Abstract:
A method and apparatus for implementing a colorless polarization independent Mach-Zehnder-interferometer (MZI)-based tunable dispersion compensator (TDC) that has only three MZI stages (two in a reflective MZI-TDC ) and two adjustable couplers which are responsive to one control voltage, making it compact, low power, and simple to fabricate, test, and operate. Polarization independence is obtained by using a half-wave plate positioned across the midpoints of the two path lengths of middle stage MZI of the three stage MZI-TDC and by using a quarter-wave plate in front of a reflective facet of the reflective MZI-TDC. A cascaded MZI-TDC arrangement with also only a single control is formed by cascading two MZI-TDC arrangements and driving all adjustable couplers with the same control signal.
Abstract:
A method and apparatus for implementing a new type of colorless Mach-Zehnder-interferometer (MZI)-based tunable dispersion compensator (TDC) that has only three MZI stages (two in a reflective version) and two adjustable couplers which are responsive to one control voltage, making it compact, low power, and simple to fabricate, test, and operate.
Abstract:
A method and apparatus are disclosed for selectively passing or blocking an optical signal using an opaque or reflective shutter that is selectively positioned in or out of the light path. The disclosed wavelength blocker can be employed to filter input wavelength-division multiplexed (WDM) signal comprised of N wavelength channels, where a mechanical shutter array selectively passes each of the N wavelength channels. Each mechanical shutter may be controlled, for example, by a micromachine control element that physically lifts the shutter into or out of the lightpath. The disclosed wavelength blockers may be utilized in wavelength-selective cross connects, as well as other optical devices. In an exemplary wavelength-selective cross connect, an array of mirrors are employed in a planar waveguide having two sets of waveguide gratings intersecting at an angle. The mirrors and waveguide gratings are positioned such that if the mirror for a given channel is up (removed from the light path), then that channel passes across the device and exits the corresponding output port (bar state), otherwise the light is reflected by the mirror and exits the opposite output port (bar state).
Abstract:
A method and apparatus are disclosed for adjusting the phase of an optical signal by varying the path length of the optical signal using one or more moveable mirrors. The phase adjustment techniques of the present invention may be employed in various optical devices, including 1×n optical switches. The position of the mirrors may be controlled, for example, using micromachined control elements that physically move the mirror along the lightpath. An exemplary 2-by-2 optical switch includes two waveguides configured to include a coupler region. A mirror is positioned at the output of each waveguide. The position of at least one of the mirrors may be adjusted along the optical path and the mirrors reflect the light exiting from the end of the waveguides back into the same waveguide after an adjustable phase delay due to the round trip through an adjustable air gap between the waveguides and corresponding mirrors. A received optical signal is split in the coupler region into two generally equal components and the phase of at least one component of the optical signal is adjusted by controlling the relative position of the mirrors. The optical components are then recombined and the optical signal appears at the appropriate output port of the optical switch. The present invention may also be applied in wavelength selective optical switches that support multiple optical channels. A number of techniques are also disclosed for fabricating optical devices in accordance with the present invention.
Abstract:
A hang tag is disclosed. The hang tag has first and second surfaces, which are preferably planar. A slot is defined between the first and second surfaces. Desirably, the slot extends at least about 0.25 inches in one direction and at least about 1 inch in another direction. Also disclosed is a method and an apparatus for automatically applying a hang tag to an elongated object (e.g., an electrical cord such as a cord set), with a machine that is suitable for applying a securement strap to an object. The method includes providing a hang tag having a slot therein. The hang tag is aligned with the machine so that when the securement strap is ejected from the machine, it passes through the slot, forms a loop around the elongated object, and is tensioned around the object. As such, the securement strap serves to attach the hang tag to the elongated object in a stationary manner.