摘要:
This invention relates to a method of making optical fiber having low polarization dependence. Light propagating through a cladding thereof has a mode group having a first eigenmode propagating at a first speed and a second eigenmode propagating at a second speed. Manufacture of the fiber is controlled so that a difference between the first and second speeds is small. A difference between the speeds divided by the first speed is preferably less than 5×10−7.
摘要:
This invention relates to an acousto-optical tunable filter generally of the kind described in U.S. Pat. No. 6,266,462. More specifically, the invention relates to a filter and its construction, the filter including a support, first and second mounts at spaced locations on the support, an optical fiber having first and second mounted portions secured to the first and second mounts respectively and a filtering section between the first and second mounted portions, a signal generator operable to generate a periodic signal, and an electro-acoustic transducer having a terminal connected to the signal generator and an actuating portion, the electric signal causing vibration of the actuating portion, and the actuating portion being connected to the filtering section so that the vibration generates a transverse wave traveling along the filtering section. The filter has an improved damper to more effectively dampen waves traveling along the filtering section.
摘要:
An apparatus is provided in which multiple devices are connected in series forming a signal path through which a signal propagates. Each device may have one or more operating frequencies and each operating frequency may generate a corresponding intensity modulation with respect to the signal. For one embodiment, the apparatus includes multiple delay lines through which the signal travels. The length of each delay line is configured to reduce the intensity modulation generated by each device based upon one or more factors including the one or more operating frequencies associated with each device and multiple null orders corresponding to different lengths of the delay lines.
摘要:
This invention relates to a method of making optical fiber having low polarization dependence and an acousto-optical filter with low PDL. A section of the fiber is heated and then allowed to cool. At least the heating is controlled to reduce stresses in a cladding layer surrounding a core of the interaction length after the interaction length is allowed to cool to reduce polarization dependence of the cladding layer. Preferably, at least time and temperature of heating is controlled.
摘要:
A method to reduce optical intensity modulation is described that involves generating a spiraling wave onto an acoustic-optic interaction portion of an optical fiber within an acousto-optic filter in order to create reflected waves that are orthogonal with respect to waves that are originally launched onto the interaction portion. A transducer is described having a first section and a second section. The first and second sections each have a polling direction along a first axis. The transducer also has a third section and a fourth section. The third and fourth sections each have a polling direction along a second axis. The third and fourth sections are each between the first and second sections. An acousto-optic filter having a horn with an elliptical cross section coupled to a transducer is also described. A transducer for an excitation element capable of launching spiraling acoustic waves is described.
摘要:
A system and method for imaging of a sample, e.g., biological sample, are provided. In particular, at least one source electro-magnetic radiation forwarded to the sample and a reference may be generated. A plurality of detectors may be used, at least one of the detectors capable of detecting a signal associated with a combination of at least one first electro-magnetic radiation received from the sample and at least one second electro-magnetic radiation received from the reference. At least one particular detector may have a particular electrical integration time, and can receive at least a portion of the signal for a time duration which has a first portion with a first power level greater than a predetermined threshold and a second portion immediately preceding or following the first portion. The second portion may have a second power level that is less than the predetermined threshold, and extends for a time period which may be, e.g., approximately more than 10% of the particular electrical integration time.
摘要:
Exemplary embodiments of methods, arrangements and systems for obtaining information about a sample can be provided. For example, in one exemplary embodiment, it is possible to receive a first electro-magnetic radiation from a sample which is based on a second electro-magnetic radiation forwarded to the sample. The first electro-magnetic radiation may have a first frequency and the second electro-magnetic radiation may have a second frequency which is different from the first frequency. The difference between the first and second frequencies can be based on an acoustic wave inside the sample related to at least one characteristic of the sample. Further, it is possible to receive at least a portion of the first electromagnetic radiation and separate it into a particular finite number (N) of frequency component radiations. In addition, it is possible to receive a particular energy of more than 1/N of energy of the third electro-magnetic radiation, and generate information associated with the sample. Certain exemplary embodiments of the present invention are capable of obtaining information associated with a sample, particularly its mechanical properties, non-contact using electromagnetic radiation.
摘要:
An apparatus and method are provided. In particular, at least one first electro-magnetic radiation may be provided to a sample and at least one second electro-magnetic radiation can be provided to a non-reflective reference. A frequency of the first and/or second radiations varies over time. An interference is detected between at least one third radiation associated with the first radiation and at least one fourth radiation associated with the second radiation. Alternatively, the first electro-magnetic radiation and/or second electro-magnetic radiation have a spectrum which changes over time. The spectrum may contain multiple frequencies at a particular time. In addition, it is possible to detect the interference signal between the third radiation and the fourth radiation in a first polarization state. Further, it may be preferable to detect a further interference signal between the third and fourth radiations in a second polarization state which is different from the first polarization state. The first and/or second electro-magnetic radiations may have a spectrum whose mean frequency changes substantially continuously over time at a tuning speed that is greater than 100 Tera Hertz per millisecond.
摘要:
A system, process and software arrangement are provided to compensate for a dispersion in at least one portion of an image. In particular, information associated with the portion of the image is obtained. The portion of the image can be associated with an interference signal that includes a first electromagnetic radiation received from a sample and a second electromagnetic radiation received from a reference. The dispersion in the at least one portion of the image can be compensated by controlling a phase of at least one spectral component of the interference signal.
摘要:
Arrangements and methods are provided for obtaining information associated with an anatomical sample. For example, at least one first electro-magnetic radiation can be provided to the anatomical sample so as to generate at least one acoustic wave in the anatomical sample. At least one second electro-magnetic radiation can be produced based on the acoustic wave. At least one portion of at least one second electro-magnetic radiation can be provided so as to determine information associated with at least one portion of the anatomical sample. In addition, the information based on data associated with the second electro-magnetic radiation can be analyzed. The first electro-magnetic radiation may include at least one first magnitude and at least one first frequency. The second electro-magnetic radiation can include at least one second magnitude and at least one second frequency. The data may relate to a first difference between the first and second magnitudes and/or a second difference between the first and second frequencies. The second difference may be approximately between −100 GHz and 100 GHz, excluding zero.