Data associated with at least one building condition or status is sensed by one or more sensors. The data from these sensors may be sent over a data bus and received by the central computer. In addition, a modulated signal may be transmitted by one or both of the transmitters across the data bus. The modulated signal is received at the receiver, which analyzes the received modulated signal, and determines whether an intermittent fault has occurred on the data bus based upon the analyzing. For example, the receiver may compare the received signal to an expected pattern and when a discrepancy exists, an intermittent fault is determined to exist. The receiver may also determine the location of the fault based upon the analysis.

System and method of detecting and locating intermittent and other faults

We report on a wavelength-tunable filter based on multimode interference (MMI) effects. A typical MMI filter consists of a multimode fiber (MMF) spliced between two single-mode fibers (SMF). The peak wavelength response of the filter exhibits a linear dependence when the length of the MMF is modified. Therefore a capillary tube filled with refractive-index-matching liquid is used to effectively increase the length of the MMF, and thus wavelength tuning is achieved. Using this filter a ring-based tunable erbium-doped fiber laser is demonstrated with a tunability of 30 nm, covering the full C-band.

Tunable multimode-interference bandpass fiber filter

A client unit and a method are provided performing fault analysis in a Passive Optical Network, PON, by using Optical Time Domain Reflectometry, OTDR. The method comprises triggering a new OTDR measurement, wherein a previous reference measurement has been made indicating an original state of the PON. The method further comprises inserting an OTDR measurement signal into a multistage splitter before a last splitter stage of the multistage splitter, and wherein the last splitter stage is of ratio 2:N; and obtaining at least one new event location based on the OTDR measurement signal. Further, the method comprises calculating a fault magnitude at a given location by subtracting an event magnitude obtained from the new OTDR measurement from the reference OTDR measurement and taking into account the number of drop links connected to the last splitter stage in the reference measurement and the new measurement. Thereby, determination of position and severity of the fault locations is enabled.

Optical time domain reflectometry (OTDR) trace analysis in PON systems

Signals are transmitted from at least one transmitter that is positioned in an electrical network. The signals that have been transmitted are received by the at least one single receiver at a single receiver positioned within the electrical network. At the single receiver, the received signals are analyzed and a determination from the analyzing the received signals is made as to whether a fault has occurred in the electrical network.

System and method of detecting and locating intermittent electrical faults in electrical systems

We propose a tunable erbium doped fiber laser based on a Fabry-Perot (F-P) cavity tuned by an electrostatic actuator. The device is made of single crystalline silicon. The F-P cavity consists of two Bragg mirrors, one being displaced by a comb-drives actuator. The F-P cavity, grooves for optical fibers and electro-mechanical structure are fabricated by deep reactive ion etching on a 70 μm silicon on insulator wafer and are integrated in a ring fiber laser. The resulting tunable fiber laser has a tuning range of 35 nm in the C-band and a spectral width of less than 0.06 nm. The maximum applied voltage for full tuning of the laser is 37 V. The mechanical resonance frequency of the actuated mirror is 14.4 kHz allowing fast tuning of the laser. The maximum output power is 1.8 mW.

Tunable Fiber Laser Using a MEMS-Based in Plane Fabry-Pérot Filter

We report the development of a ring tunable fiber laser based on tunable fiber Bragg gratings (TFBG) integrated with an optical circulator. The TFBG is embedded inside a 3-piont bending device for wavelength tuning. The tunable laser operating in the C-band has power variation, tuning resolution, tuning range and laser line width of ±0.5 dB, 0.5 nm, 25.0 nm and less than 0.05 nm, respectively. As 40 mW of pump power is used, the ring tunable laser has a side mode suppression ratio of 60 dB and a power conversion efficiency of 25%. These specifications ensure the high-quality operation of a tunable laser.

C-band continuously tunable lasers using tunable fiber Bragg gratings

A detection system that performs in a passive optical network is disclosed. The detection system uses a central office to provide detection signals to corresponding fiber branches for obtaining different reflected signals based on different optical network models. Hence, the central office can determine whether fiber branches in the passive optical network has a fault and where the fault is according to the reflected signals.

Detection system for identifying faults in passive optical networks

We propose an N-channel power-compensated reconfigurable optical add/drop multiplexer (ROADM) based on using fiber Bragg gratings (FBGs). Both tunable FBGs and wavelength-fixed FBGs are used in this ROADM. By using the dual-pass amplification scheme with two pieces of erbium doped fibers, an 8.0dB optical net gain has been achieved with a gain variation less than ±0.5 dB for each add/drop/pass-through channel. System performance was studied for a four-WDM-channel 10Gb/s x 100-km lightwave transmission trial network and bit error rate of 10 -9 is observed for the 50km added signal, 100km pass-through signal and 50km dropped signal at -18.3, -19.4 and -18.9 dBm received power, respectively. Only 1.1 dB of power penalty was observed compared to the back-to-back transmission.

Reconfigurable Optical Add/Drop Multiplexer with 8.0 dB Net Gain Using Dual-Pass Amplified Scheme

Parameters optimization of high efficiency discrete Raman fiber amplifier by using the coupled steady-state equations

PROBLEM TO BE SOLVED: To provide a fracture point detection system of a passive optical line network. SOLUTION: A monitor light signal is supplied to an optical fiber branch route by a main control domain, and the optical fiber branch route feedbacks a different reflected light signal to the main control domain by a different passive optical line network structure. Hereby, an optical spectrum analyzer and an optical time-domain reflection measuring device in the main control domain determine whether a fracture point is generated on the optical fiber branch route of the passive optical line network or not, or a position of the fracture point, based on a fed-back reflected light signal. COPYRIGHT: (C)2009,JPO&INPIT

Yi-Tseng Lin

Papers

C-band continuously tunable lasers using tunable fiber Bragg gratings

Detection system for identifying faults in passive optical networks

Reconfigurable Optical Add/Drop Multiplexer with 8.0 dB Net Gain Using Dual-Pass Amplified Scheme

Parameters optimization of high efficiency discrete Raman fiber amplifier by using the coupled steady-state equations

Fracture point detection system of passive optical line network