Wavelength tunable filter device

a filter device and wavelength technology, applied in the field of wavelength tunable filters, can solve the problems of limiting the rotational angular resolution of the diffraction grating, the hysteresis of the reduction gear in the rotational direction, and the inability to achieve high resolution characteristics

US20020071634A1Inactive Publication Date: 2002-06-13PANASONIC CORP
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Patent Information

Authority / Receiving Office
US · United States
Current Assignee / Owner
Publication Date
2002-06-13
Estimated Expiration
Not applicable · inactive patent

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Abstract

A wavelength tunable filter device has at least two optical fibers through which an optical signal is input or output; a wavelength selective element which the optical signal is input to and output from through a lens and which selects a wavelength; a mounting jig to which the wavelength selective element is fixedly secured; a rotating mechanism, having an ultrasonic motor and an encoder, for rotating the wavelength selective element; and a motor controller for controlling the ultrasonic motor for driving, wherein the mounting jig is rigidly mounted directly to a rotating shaft of the ultrasonic motor, and the amount of power that does not exceed the driving power necessary to cause the ultrasonic motor to start rotating from a stopped condition is intermittently applied to the motor controller.
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Description

[0001] 1. Field of the Invention

[0002] The present invention relates to a wavelength tunable filter for use in a wavelength division multiplexing transmission system and apparatus in optical communications, and also relates to a wavelength tunable filter device using the same.

[0003] 2. Related Art of the Invention

[0004] In optical communications, there has been known a technique of wavelength division multiplexing which transmits signals of multiple channels through a single optical fiber. In wavelength division multiplexing, signals of different channels are optically multiplexed at different wavelengths by using a optical multiplexer at the transmitting end, and the thus multiplexed signals are transmitted through a single fiber to the receiving end; at the receiving end, the multiplexed signals are separated according to their wavelengths by means of a wavelength filter, to recover the original signals. In particular, by using a wavelength tunable filter whose wavelength is capab...

Examples

Embodiment Construction

[0032] One embodiment of the wavelength tunable filter device of the present invention will be described with reference to FIGS. 1 and 2.

[0033] FIG. 1 shows the configuration of the wavelength tunable filter device according to the embodiment. In FIG. 1(a), reference numerals 101 and 102 are diffraction gratings, 5 is a mounting jig, 2 is a lens, 3 is an input fiber, 4 is an output fiber, 8 is an optical-to-electrical converter, 9 is an intensity level detector, 10 is a rotational position calculator, 13 is a rotational position storage, 14 is a rotational position detector, 11 is a rotational speed adjuster, 12 is a motor driver, 6 is an ultrasonic motor, 7 is a laser encoder, and 15 is a joint.

[0034] The ultrasonic motor 6 is a motor that induces surface acoustic waves between opposing disks placed within the motor, thereby generating a slipping motion between the disks and causing a shaft fixed to the movable disk to rotate. The laser encoder 7 is capable of generating more outpu...