Abstract:
An optical network monitoring system and method thereof are proposed. An optical line terminal (OLT) transmits a first optical signal to a plurality of optical interference devices. After the first optical signal passes the optical interference devices, the optical interference devices reflect back a plurality of second optical signals corresponding to the optical interference devices respectively to the optical line terminal. The second optical signals have different optical path differences. An optical/electrical converter unit converts each of the second optical signals into an electrical signal. A spectrum analyzing unit analyzes the electrical signal to extract a frequency component of the electrical signal, thus the fiber connection status to each optical network unit in the optical network system could be obtained. Therefore, the purpose of monitoring the optical network system is achieved.
Abstract:
A non-sampling-based Q-factor measuring apparatus and method use a power conversion module to transform the power variation of inputted optical signals in time domain into the variation in other domains, such as optical wavelength, optical polarization and different output ports of optical elements. Taking optical wavelength as an example, different levels of power variation respond different outputs of wavelength variation through the use of a power-to-wavelength conversion module. An optical filter then separates the inputted optical signals with different wavelengths. The power average of a wavelength for its corresponding optical signals is further calculated by a photo detector. Thereby, the information of the power variation for the inputted optical signals at levels 1 and 0 can be obtained, and the Q-factor for the inputted optical signals is easily measured.
Abstract:
An apparatus and method for simultaneous channel and optical signal-to-noise ratio (OSNR) monitoring is adapted to function in multi-channel wavelength-division-multiplexed (WDM) optical communication systems. A polarization controller is sequentially adjusted to perform the sequential polarization control with an optical signal. A polarization-selective electro-optic modulator acts as a polarizer and provides a signal dithering to improve the detection sensitivity. A beam splitter splits the dithered optical signal into two clusters. A photodetector receives the first cluster and measures the OSNR. An optical element receives the second cluster and monitors the channel wavelength of multiple channels. The apparatus can be packaged into a compact module and integrated on a chip. The channel monitoring covers a wide wavelength range and is tunable. The OSNR monitoring can be accurate over a wide dynamic range.
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:
The present invention provides a wavelength converter with wideband four-wave-mixing, which includes a laser diode, an optical modulator, a first and a second polarization controllers, a first, a second and a third tunable lasers, an optical coupler, a semiconductor optical amplifier (SOA) and a multiplexer. The present invention utilizes an assist beam that can improve the recovery rate and saturation power of the SOA. While the SOA is operated at a bias current close to the transparent condition for the assist beam, it does not influence the gain of the SOA wavelength converter.
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:
This invention demonstrates an adjustable monolithic multi-wavelength laser diode array formed on a substrate a plurality of diode lasers, each has an active section and two mirrors with similar multiple reflectivity peaks. A phase control section can also be included in each laser for fine tuning of the laser wavelength. Each laser in the laser array can emit light at the same wavelength or can be easily tuned to form an array with multiple wavelengths. To serve as an application example of this invention, sampled grating DBR lasers are designed to form a laser array with adjustable multi-wavelength outputs. By varying from laser to laser the sampling periods of the sampled gratings in each laser, a uniformly-spaced multi-wavelength laser array can be achieved with a simple tuning mechanism. The lasers can also emit light at the same wavelength or be tuned to other wavelengths by tuning the sampled grating mirrors. The technique for fabricating the laser array is similar to that for conventional DBR lasers and is already well established. The invented multi-wavelength laser arrays can find applications in WDM systems to offer the advantages of high performance, high reliability, compact size, and high speed.
Abstract:
A method for larger-area fabrication of uniform silicon nanowire arrays is disclosed. The method includes forming a metal layer with a predetermined thickness on a substrate whose surface has a silicon material by a coating process, the metal layer selected from the group consisting of Ag, Au and Pt; and performing a metal-induced chemical etching for the silicon material by using an etching solution. Accordingly, a drawback that Ag nanoparticles are utilized to perform the metal-induced chemical etching in prior art is solved.
Abstract:
A method for etching high-aspect-ratio features is disclosed. The method is applicable in forming a nanoscale deep trench having a smooth and angle-adjustable sidewall. The method includes: forming a patterned photoresist layer on a surface of a silicon substrate for exposing a part of the silicon substrate; and supplying a process gas simultaneously containing sulfur hexafluoride (SF6) and fluorinated carbon composition into a chamber in which the substrate in positioned for carrying out a deep reactive ion etching operation to etch the part of the silicon substrate for forming the deep trench. The method forms a nanoscale deep trench with a high silicon-to-photoresist etching selectivity.
Abstract:
A reconfigurable optical amplifier including a first reversible optical circulator and an optical gain device is provided. The first reversible optical circulator has four I/O ports which are respectively referred to as a first terminal, a second terminal, a third terminal, and a fourth terminal. The four I/O ports sequentially transmit an optical signal in a transmission direction of a forward circulation or a backward circulation according to a control signal. The first terminal is isolated from the adjacent fourth terminal. The optical gain device is connected between the first terminal and the adjacent fourth terminal. The second terminal and the third terminal are respectively connected to a first communication node and a second communication node.