摘要:
A filter for generating an output light signal having one or more output spectral lines selected from a plurality of potential spectral lines contained in an input light signal. The filter includes a channel filter for filtering the input light signal to create a notched light signal having a spectrum devoid of light at a first wavelength. The filter also includes a variable wavelength reflector for reflecting light having a wavelength equal to a reflection wavelength, the reflection wavelength being selectable from the first wavelength and a second wavelength equal to the wavelength of one of the spectral lines. The output of the channel filter is coupled to the input of the variable wavelength reflector. The output of the variable wavelength reflector includes the output light signal. The channel filter can be constructed using a number of known optical components such as fiber Bragg reflectors, array waveguide filters, Mach Zehnder filters, or absorption filters. The variable frequency reflector is preferably constructed from one or more variable frequency fiber Bragg reflectors.
摘要:
An optical communication assembly includes a demultiplexer coupled to an input fiber, a multiplexer coupled to an output fiber and a plurality of optical fibers. Each optical fiber is coupled to one or both of the demultiplexer and multiplexer. A plurality of attenuators are each coupled to an optical fiber in the pluality of optical fibers.
摘要:
A drop AOTF has a first AOTF that includes an optical fiber with a longitudinal axis, an acoustic wave propagation member with a proximal end and a distal end and an acoustic wave propagation member. The acoustic wave propagation member propagating an acoustic wave from the proximal to the distal end of the acoustic wave propagation member. An optical circulator, with first, second and third ports, is coupled to the first AOTF at the third port. A mode coupler is coupled to the first AOTF. A orthogonal-polarization reflective mirror is coupled to the mode coupler.
摘要:
An apparatus and method for measuring the thickness of a film having top and bottom surfaces. The apparatus includes a first coupler for generating a first probe light signal and a second probe light signal from a low coherence light source. The first probe light signal is directed toward the top surface of the film at a first angle of incidence and the light leaving the top surface of the film is collected. Similarly, the second probe light signal is directed toward the top surface of the film at a second angle of incidence different from said first angle of incidence and the light leaving the top surface of the film is also collected. The collected light is combined to form a collected light signal which is input to a receiver that determines the time delay between light reflected from the top and bottom surfaces of the film. In the preferred embodiment of the present invention, the receiver is constructed from an optical autocorrelator or an optical spectrum analyzer that includes circuitry for providing the Fourier transform of the frequency domain spectrum measured from the combined light signal.
摘要:
A figure-8 loop laser having a controllable phase shifter in a Sagnac loop (non-linear amplifying loop mirror). A half-wave plate in series with Faraday optical rotators provide a switchable non-reciprocal 180-degree phase shifter that allows the birefringence of the fiber loop to be adjusted during continuous wave operation. The phase shifter is activated during continuous wave operation to find a minimum threshold and then is turned off, placing the laser in optimum state for mode locking.
摘要:
An improved optical low-coherence reflectometer is disclosed for use in measuring the strength and location of optical reflections. The invention utilizes a reference signal comprising multiple copies of a light signal to increase the range of distance measurements over which the reflectometer operates. Each copy of the light signal is delayed by a different amount. Embodiments in which the copies are generated with a ring resonator, a Fabry-Perot cavity, and multiple fiber delay lines are described.
摘要:
An optical coherence-domain reflectometry system provides an interferometer driven by a broadband incoherent light source with the device under test connected to one arm of the interferometer and a movable scanning mirror in the other arm providing a reference signal. The mirror moves at a controlled velocity to produce a Doppler shift in the reference signal frequency. The reference signal arm also includes a piezoelectric transducer which modulates the phase of the reference signal at a given frequency, causing a further shift in the reference signal frequency. The interference signal is detected and measured by a polarization diversity receiver. A linear polarizer in the reference signal arm is adjusted to produce equal reference signal powers in each arm of the polarization diversity receiver in the absence of a reflection signal from the test arm. The measured reflectometry signal is substantially independent of the state of polarization of the reflected signal from the device under test.
摘要:
A hybrid network optical communication system is provided. The system may include a central office, at least one network group coupled to the central office. The network group may include a plurality of external rings, and each of the external rings may include a plurality of nodes having a ring connection. This system may have economical advantages of reducing the number of optical cores and easily switching directions for protecting the system when any problems occur on the optical cores and the devices at nodes.
摘要:
Embodiments of a periodically filtered broadband light source are described. The periodically filtered broadband light source includes a periodic spectral filter coupled to an optical gain element to generate a light and to filter the light into a plurality of individual spectral slices. The broadband light source includes an isolator coupled to the optical gain element. The periodic filter can be a reflective filter. The periodic filter can adjust an optical power in each of the spectral slices. The periodic filter can include one or more control elements to control an optical power in each of the spectral slices. Further, a wavelength division multiplexing passive optical network system is described that includes the periodic broadband light source to send individual spectral slices to wavelength lock one or more transceivers. The individual spectral slices sent by the periodic broadband light source match wavelength channels of a wavelength division multiplexer/de-multiplexer.
摘要:
Methods and apparatuses to provide an “Open access” service model using wavelength division multiplexing (“WDM”) passive optical networks (“PONs”) are described. A cross-connect is used to supply a first set of optical signals corresponding to a first service provider and a second set of optical signals corresponding to a second service provider to a WDM multiplexer/demultiplexer. The WDM multiplexer/de-multiplexer is used to multiplex and transmit the first set and the second set to a remote location. Another WDM multiplexer/de-multiplexer at the remote location is used to de-multiplex the first set and the second set. The first set may be supplied to a first user and the second set may be supplied to a second user. Transceivers coupled to the cross-connect may be used to generate the optical signals. For one embodiment, the transceivers include a wavelength-locked light source. For one embodiment, the transceivers are alike.