Abstract: An apparatus and method for treating a substrate are provided. The apparatus includes at least one first process chamber configured to supply a developer onto the substrate; at least one second process chamber configured to treat the substrate using a supercritical fluid; a transfer chamber configured to transfer the substrate from the at least one first process chamber to the at least one second process chamber, while the developer supplied in the at least one first process chamber remains on the substrate; and a temperature and humidity control system configured to manage temperature and humidity of the transfer chamber by supplying a first gas of constant temperature and humidity into the transfer chamber.

Abstract: The present invention provides a method and an apparatus for monitoring optical signal to noise ratio (OSNR) in a wavelength division multiplexing optical transmission system. The present invention utilizes a polarization nulling method and a tunable optical bandpass filter in order to reliably monitor the OSNR by considering a finite polarization nulling ratio, polarization mode dispersion and non-linear birefringence of the optical system in real time measurement of the OSNR. Further, the tunable optical bandpass filter is controlled to filter all wavelength bands of wavelength division multiplexed signals. Since the invention may monitor a plurality of demultiplexed optical signals with a single apparatus, the overall cost of the OSNR monitoring equipment is significantly reduced.

Abstract: An apparatus for monitoring polarization-mode dispersion and chromatic dispersion in optical networks in accordance with the present invention comprises; an optical distributor for distributing input optical signals, a first light receiver for photoelectrically converting the optical signals distributed by the distributor, a second light receiver for photoelectrically converting the optical signals to measure the average power of the optical signals distributed by the distributor, a filter for filtering output signals from the first light receiver, a power meter for measuring the frequency band of the optical signals filtered by the filter, an analog-to-digital (A/D) converter for converting the analog signals from the first and the second receivers into digital signals, a microprocessor for monitoring the polarization-mode dispersion and the chromatic dispersion of the optical signals by means of the digital signals from the A/D converter, and further a polarization scrambler in the optical signal sending-en

Abstract: The present invention provides a method and an apparatus for monitoring optical signal to noise ratio (OSNR) in a wavelength division multiplexing optical transmission system. The present invention utilizes a polarization nulling method and a tunable optical bandpass filter in order to reliably monitor the OSNR by considering a finite polarization nulling ratio, polarization mode dispersion and non-linear birefringence of the optical system in real time measurement of the OSNR. Further, the tunable optical bandpass filter is controlled to filter all wavelength bands of wavelength division multiplexed signals. Since the invention may monitor a plurality of demultiplexed optical signals with a single apparatus, the overall cost of the OSNR monitoring equipment is significantly reduced.

Abstract: A multiplexing/demultiplexing apparatus used in wavelength division multiplexed passive optical subscriber networks comprises a multiplexing/demultiplexing means each having a natural number N input and output ports, wherein wavelength divided signals in one direction inputted through the N−1 input ports are multiplexed onto one output port, and simultaneously wavelength division multiplexed signals in the other direction inputted through the remainder one input port are demultiplexed onto the remainder N−1 output ports. According to the present invention it is possible to implement economical and efficient wavelength division multiplexed passive optical subscriber networks, by including two WGR's, one at the central office and one at the remote node to perform simultaneous multiplexing and demultiplexing of signals in upstream and downstream, and employing an erbium-doped fiber amplifier to be able to use a low-cost light source such as a light-emitting diode.

Abstract: An apparatus monitoring frequency of WDM signals using pilot tone and two interleaved solid etalon filters for efficient management and maintenance of wavelength division multiplexing optical transmission network is provided. Desirably, the apparatus for optical frequency monitoring includes splitting means, a plurality of optical filtering means, optical detecting means, and frequency detecting means. The splitting means splits optical signal and the optical signal includes pilot tone. The plurality of optical filtering means filters an output of the splitting means with particular passband. The optical detecting means converts an output of the optical filtering means into electrical signal. The frequency detecting means detects an intensity of the pilot tone from an output of the optical detecting means and calculates optical frequency.

Abstract: An apparatus for monitoring polarization-mode dispersion and chromatic dispersion in optical networks in accordance with the present invention comprises; an optical distributor for distributing input optical signals, a first light receiver for photoelectrically converting the optical signals distributed by the distributor, a second light receiver for photoelectrically converting the optical signals to measure the average power of the optical signals distributed by the distributor, a filter for filtering output signals from the first light receiver, a power meter for measuring the frequency band of the optical signals filtered by the filter, an analog-to-digital (A/D) converter for converting the analog signals from the first and the second receivers into digital signals, a microprocessor for monitoring the polarization-mode dispersion and the chromatic dispersion of the optical signals by means of the digital signals from the A/D converter, and further a polarization scrambler in the optical signal sending-en

Abstract: The optical signal-to-noise ratio (OSNR) of optical signals that are demultiplexed into a plurality of optical channels by a wavelength-division multiplexing (WDM) optical transmission system is monitored by an apparatus which outputs the optical signals of each optical channel on a first path and a second path, and measures the signal intensity of each of the optical signals on the first path. The apparatus selectively passes an AC component of each of the optical signals on the second path and processes the AC component by converting the AC component into a digital signal and performing a fast fourier transform on the digital signal. The apparatus measures the noise intensity of the processed AC component on the second path. The OSNR of each optical signal is calculated by comparing the measured signal intensity of each of the optical signals and the measured noise intensity of the processed AC component of each of the optical signals.

Abstract: A cold-start wavelength-division-multiplexed (WDM) optical transmission system uses a synchronized etalon filter, DFB lasers and passive optical demultiplexers. The DFB lasers are tested under normal operating conditions and wavelength-selected for each channel. The wavelength selection is such that the laser operates within one half of the channel spacing from the standardized wavelength. For the cold-start operation, each laser is able to automatically find its operating wavelength without any prior knowledge of its operating conditions for the standardized wavelength. In addition, this system simultaneously adjusts the output power of each laser to a desired value.