Abstract: Methods for allocating transmission bandwidths of a network are adapted to a network including an office terminal and peripheral terminals. The peripheral terminals communicate with the office terminal by time division multiplexing during a sequence of transmitting cycles. The method includes receiving requested bandwidths from uploading messages delivered from the peripheral terminals, arranging an uploading order of the peripheral terminals based on the uploading messages to obtain a transmitting sequence, adjusting the uploading order of each of the peripheral terminals in the transmitting sequence based on a size of the requested bandwidth to obtain a modified transmitting sequence, and arranging a modified uploading order of the peripheral terminals based on the modified transmitting sequence. Therefore, the transmission bandwidth allocation is fairer, and delay is reduced. Upstream order of each terminal is transferred based on its requested bandwidth, thereby effectively reducing the average delay.

Abstract: A communications system includes an optical receiver for receiving optical signals and for converting the optical signals into electrical signals, a transimpedance amplifier (“TIA”) for filtering the electrical signals, a limiting amplifier coupled with the TIA, an automatic threshold control (“ATC”) coupled with the TIA for providing a reference voltage for the limiting amplifier. The ATC further includes a common emitter circuit and an emitter follower circuit, wherein logic high signals and logical low signals in the electrical signals are determined based on the reference voltage output from the ATC.

Abstract: Methods for allocating transmission bandwidths of a network are adapted to a network including an office terminal and peripheral terminals. The peripheral terminals communicate with the office terminal by time division multiplexing during a sequence of transmitting cycles. The method includes receiving requested bandwidths from uploading messages delivered from the peripheral terminals, arranging an uploading order of the peripheral terminals based on the uploading messages to obtain a transmitting sequence, adjusting the uploading order of each of the peripheral terminals in the transmitting sequence based on a size of the requested bandwidth to obtain a modified transmitting sequence, and arranging a modified uploading order of the peripheral terminals based on the modified transmitting sequence. Therefore, the transmission bandwidth allocation is fairer, and delay is reduced. Upstream order of each terminal is transferred based on its requested bandwidth, thereby effectively reducing the average delay.

Abstract: Methods for allocating transmission bandwidths of a network are provided. The allocation ratio of anticipation bandwidths is adjusted according to the loading of the network to calculate the requested bandwidths, thereby effectively reducing an average delay and enhancing the utility rate of the network. Further, remaining bandwidth of the network is allocated based on maximum used bandwidth and bandwidth compensation of each terminal during the transmission cycle, to allocate excess bandwidth for each terminal. Therefore, the transmission bandwidth allocation is fairer, and delay is reduced. Upstream order of each terminal is transferred based on its requested bandwidth, thereby effectively reducing the average delay.

Abstract: A communications system includes an optical receiver for receiving optical signals and for converting the optical signals into electrical signals, a transimpedance amplifier (“TIA”) for filtering the electrical signals, a limiting amplifier coupled with the TIA, an automatic threshold control (“ATC”) coupled with the TIA for providing a reference voltage for the limiting amplifier. The ATC further includes a common emitter circuit and an emitter follower circuit, wherein logic high signals and logical low signals in the electrical signals are determined based on the reference voltage output from the ATC.

Abstract: A communications system includes an optical receiver for receiving optical signals and for converting the optical signals into electrical signals, a transimpedance amplifier (“TIA”) for filtering the electrical signals, a limiting amplifier coupled with the TIA, an automatic threshold control (“ATC”) coupled with the TIA for providing a reference voltage for the limiting amplifier. The ATC further includes a common emitter circuit and an emitter follower circuit, wherein logic high signals and logical low signals in the electrical signals are determined based on the reference voltage output from the ATC.

Abstract: An apparatus and a method for monitoring optical signal-to-noise ratio are provided. It can be applied in dense wavelength-division multiplexed networks to monitor the transmission quality of each optical channel. The apparatus comprises an optical circulator, a tunable optical filter, a dithering signal, a dithered reflector, and two photodiodes. It can be integrated on a single chip. The invention utilizes the dithering and reflection functions of the dithered reflector, and passes the signal and the noise through the tunable optical filter once and twice, respectively. When the tunable optical filter is scanning and filtering the whole spectrum, the signal and noise powers are measured by the two photodiodes, respectively. The OSNR for each optical channel is then calculated according to the signal and noise powers. It can monitor channel location, wavelength drift, and OSNR by including a wavelength locker to act as an optical channel analyzer.

Abstract: Methods for allocating transmission bandwidths of a network are provided. The allocation ratio of anticipation bandwidths is adjusted according to the loading of the network to calculate the requested bandwidths, thereby effectively reducing an average delay and enhancing the utility rate of the network. Further, remaining bandwidth of the network is allocated based on maximum used bandwidth and bandwidth compensation of each terminal during the transmission cycle, to allocate excess bandwidth for each terminal. Therefore, the transmission bandwidth allocation is fairer, and delay is reduced. Upstream order of each terminal is transferred based on its requested bandwidth, thereby effectively reducing the average delay.

Abstract: An apparatus and a method for monitoring optical signal-to-noise ratio are provided. It can be applied in dense wavelength-division multiplexed networks to monitor the transmission quality of each optical channel. The apparatus comprises an optical circulator, a tunable optical filter, a dithering signal, a dithered reflector, and two photodiodes. It can be integrated on a single chip. The invention utilizes the dithering and reflection functions of the dithered reflector, and passes the signal and the noise through the tunable optical filter once and twice, respectively. When the tunable optical filter is scanning and filtering the whole spectrum, the signal and noise powers are measured by the two photodiodes, respectively. The OSNR for each optical channel is then calculated according to the signal and noise powers. It can monitor channel location, wavelength drift, and OSNR by including a wavelength locker to act as an optical channel analyzer.

Abstract: A communications system includes an optical receiver for receiving optical signals and for converting the optical signals into electrical signals, a transimpedance amplifier (“TIA”) for filtering the electrical signals, a limiting amplifier coupled with the TIA, an automatic threshold control (“ATC”) coupled with the TIA for providing a reference voltage for the limiting amplifier. The ATC further includes a common emitter circuit and an emitter follower circuit, wherein logic high signals and logical low signals in the electrical signals are determined based on the reference voltage output from the ATC.

Abstract: A passive optical network with a protection mechanism and its method of relocation are provided. A plurality of optical network units is defined in several optical network unit groups. Each optical network unit connects to two couplers. The two couplers connect respectively to two different optical line terminals, which are controlled by a controller. Thus, when the optical lines run out or are overloaded, the controller relocates the optical network units dynamically.

Abstract: There are disclosed a wavelength monitoring device of tunable laser sources and a method thereof. A Fabry-Perot etalon is provided to detect the wavelength drift, and furthermore, a Fabry-Perot laser diode or a light emitting diode is provided to recognize the channel of the wavelength. The wavelength drift is used to determine the junction voltage of each corresponding channel in advance. Then, the actually detected junction voltage of the diode is used to determine the channel of the wavelength, thereby accurately detecting the actual channel wavelength.

Abstract: There are disclosed a wavelength monitoring device of tunable laser sources and a method thereof. A Fabry-Perot etalon is provided to detect the wavelength drift, and furthermore, a Fabry-Perot laser diode or a light emitting diode is provided to recognize the channel of the wavelength. The wavelength drift is used to determine the junction voltage of each corresponding channel in advance. Then, the actually detected junction voltage of the diode is used to determine the channel of the wavelength, thereby accurately detecting the actual channel wavelength.