Kyocera Corporation

Yukiko Furukata

Yusuke Takei

Hiromi Ajima

Yasushi Sato

Michitaka Okuta

Tetsuya Suga

Michifumi Shoda

Yoshiyuki Shigeoka

An optical isolator is constructed such that an optical isolator element in which at least one flat Faraday rotator and at least two flat polarizers are bonded to each other into an integral unit by van der Waals forces or hydrogen-bonding forces acting between bonding surfaces of the Faraday rotator and the polarizers is accommodated in a tubular magnetic element.

Optical isolator element, a method for producing such an element, and an optical isolator using such an element

Provided is a wideband ASE light source, which has a high output and a little ripples in a wide band and the output of which is stable. In a wideband ASE light source constructed of a pumping light source that generates a pumping light, an erbium-doped optical fiber that generates an ASE light by incident pumping light, a reflector that is arranged at one terminal portion of the erbium-doped optical fiber and reflects the ASE light radiated from the erbium-doped optical fiber, an optical multiplexer that is arranged between a terminal portion of the erbium-doped optical fiber and the pumping light and optically multiplexes and demultiplexes the pumping light with or from the ASE light and an optical isolator that is arranged between the third terminal portion of the optical multiplexer and an output terminal and removes a return light to the erbium-doped optical fiber, the optical multiplexer has a maximum value of isolation in a wavelength band of 1570 nm to 1600 nm.

Wideband ASE light source

A broadband ASE light source is provided which comprises an amplifying optical fiber doped with rare earth; a pumping light source and an output port both which are connected to one end of the amplifying optical fiber via a multiplexer; and a reflecting or circulating member which is connected to the other end of the amplifying optical fiber, whereby the amplifying optical fiber emits ASE light containing a first and second wavelength bands through the port. Particularly, a second pumping light source may be connected to the other end of the amplifying optical fiber via another multiplexer to widen the wavelength band to longer wavelength side. Further, using the amplifying Er-doped optical fiber with the pumping light sources having wavelength of a 980 nm band, the ASE light source can emit a flattened broadband of 1530 to 1610 nm, combining the two wavelength bands of 1530 to 1570 mn and 1570 to 1610 nm. The input power supplied for the amplifying fiber from the second pumping light source may be less than 20% of the input power supplied for the amplifying fiber from the first pumping light source.

Broadband amplified spontaneous emission light source

Adapter-type optical isolator 1 has split sleeve 7 within housings A and B. Polarization-independent optical isolator is of such a structure that optical isolator device 3 which is an integral assembly of a Faraday rotator and a birefringent crystal element is provided within hollow cylindrical magnet 4. Beam changing elements 5a and 5b are in the form of optical coupling lenses or core-flared fibers. Adapter-type optical isolator 1 has the polarization-independent optical isolator and beam changing elements 5a and 5b fitted snugly within the bore of split sleeve 7 in the central area in such a way that the polarization-independent optical isolator is held between beam changing elements 5a and 5b. An optical connector using the adapter-type optical isolator 1 is simple in construction, permits simple assembly and adjustments, is small, allows for easy optical adjustments on individual optical parts, features high operational stability and can be incorporated into a wide variety of measuring instruments and communication equipment.

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Yokohama, Japan

Yukiko Furukata