摘要:
An approach for automatic Raman gain and tilt control for a WDM (Wavelength Division Multiplexing) optical communication systems is disclosed. An optical fiber carries a plurality of optical signals, in which at least one of the optical signals are reference signals. An optical gain unit (e.g., Raman pump unit) couples to the optical fiber and adjusts the reference signals to compensate, in part, for losses associated with the optical fiber and gain tilt accumulation. Upon detecting and analyzing the reference signals, a controller controls the optical gain unit and outputs a control signal to the optical gain unit based upon the analyzed reference signals. An optical amplifier is connected to the optical fiber and amplifies the optical signals. The optical gain unit provides a nearly constant power per channel at an input of the optical amplifier. Under this approach, a Raman gain control mechanism, combined with the use of gain controlled EDFA (Erbium Doped Fiber Amplifier), allows high transmission capacity over ultra-long distances without optical regeneration and with high flexibility.
摘要:
The present invention discloses a method and apparatus for cross-connecting high-speed telecommunications signals at a cross-connect apparatus. The cross-connect apparatus can transmit the telecommunications signals from an input interface card to a cross-connect card, and from the cross-connect card to an output interface card without any synchronization information. Synchronization of the signals is accomplished with circuitry contained on the interface cards and the cross-connect card. The cross-connect apparatus also includes a control unit for managing the control and timing of the apparatus.
摘要:
Methods and apparatus for providing a stage apparatus which is modular and allows for reaction force cancellation are described. According to one aspect of the present invention, a stage apparatus includes a table assembly and a first stage. The table assembly supports an object, e.g., a wafer or a reticle, which is to be moved. The first stage includes a counter mass arrangement, a plurality of carriages, and a plurality of linkages. The plurality of carriages is coupled to the table assembly through the plurality of linkages such that a first carriage and a second carriage are arranged to move in substantially opposite directions along a first axis to cause the table assembly to move along a second axis while reaction forces generated when the first carriage and the second carriage are substantially cancelled by the counter mass arrangement.
摘要:
A programmable interface for FPGA cores embedded in an integrated circuit. The interface has an interconnect multiplexer (which includes demultiplexers) connected to the FPGA core and other elements of the integrated circuit. A control portion of the interface provides selection control bits to the interconnect multiplexer to make the desired connection configuration. Programmable latches in the control portion hold the selection bits which are loaded into the latches at the same time configuration bits are loaded into the integrated circuit to program the FPGA core. Alternatively, the control portion can be implemented by another FPGA core which is configured as a state machine to generate the selection control bits.
摘要:
All-optical wavelength converters based upon difference frequency generation (DFG) in optical chips with periodically poled materials are presented. Tunable continuous wave (CW) laser sources and various arrangements are made with the optical input signals in different ITU channels. In some arrangements the laser source(s) acts as the pump for the conversion of the input signals to different wavelengths. In other arrangement, the amplified input signals acts as a pump with the laser source in the role of the input signal. The net effect is that input signals are converted to different wavelengths. One-to-any, any-to-one, and any-to-any wavelength converters are described. Simultanenous conversation can also be preformed so that bands of signals may also be converted.
摘要:
Systems and methods for sharing a single decoder among data streams originating with multiple sources. Error correction coding techniques are modified to facilitate decoding of data from multiple sources multiplexed in the time domain at the decoder input. A single decoder accommodates multiple sources that have been encoded using disparate code rates. One application is an OFDM point to multipoint system.
摘要:
Raman amplification of a WDM signal with excellent gain flatness across a very large bandwidth is achieved. Co-propagating and counter-propagating Raman pumping are combined in the same fiber. Multiple pumping wavelengths are employed. Wavelengths employed for co-propagating pumping and wavelengths employed for counter-propagating pumping alternate in order of wavelength. In one embodiment, N co-propagating pump wavelengths and N+1 counter-propagating pump wavelengths are used. Alternatively, one may use N+1 co-propagating pump wavelengths and N counter-propagating pump wavelengths.
摘要:
Techniques for implementing caches for context switching applications are provided. A context identifier is stored in the cache to indicate the context to which data in the cache is associated. Additionally, the context can have different priorities so that storage space in the cache can be more efficiently allocated to the contexts based on their priorities.
摘要:
An apparatus for in-situ injection of one or more chemical components into a reaction chamber is disclosed. The apparatus includes a reaction chamber for receiving one or more libraries, each of the libraries comprising two or more samples. The reaction chamber is configured to form a sealed enclosure. The apparatus further includes an injection manifold supporting injectors for in-situ injection of one or more chemical components onto respective samples of the one or more libraries in the pressurized sealed reaction chamber.
摘要:
A dithering signal is superimposed on a laser frequency control signal. In this way, laser frequency control may be achieved by employing measurements from a single photodetector. By sampling synchronously to the dithering signal, it is possible to generate both the magnitude end sign of the current frequency error based on the output of a single photodetector. This reduces the number of components required to generate an optical signal and is particularly advantageous in WDM systems where laser frequency control components may be duplicated over a large number of channels.