Optical fiber apparatus provided with demultiplexing/multiplexing unit on fiber's end portion, optical detecting apparatus provided with demultiplexing/multiplexing unit on its light receiving surface, and optical transmission system using the same

An optical fiber apparatus comprising:

• an optical fiber having an optical axial direction and an end face;
• and
• demultiplexing/multiplexing means provided or formed directly on at least said end face of said optical fiber,
• wherein said demultiplexing/multiplexing means demultiplexes or multiplexes a light wave of at least a wavelength with a wavelength spectrum that is determined by a resolving power of said demultiplexing/multiplexing means, and
• wherein said demultiplexing/multiplexing means comprises:
• parallel reflective films;
• and
• an optical material sandwiched between said reflective films,
• wherein said optical material has a predetermined refractive-index distribution.

An optical fiber apparatus comprising:

• an optical fiber having an optical axial direction and an end face;
• and
• demultiplexing/multiplexing means provided or formed directly on at least said end face of said optical fiber,
• wherein said demultiplexing/multiplexing means demultiplexes or multiplexes a light wave of at least a wavelength with a wavelength spectrum that is determined by a resolving power of said demultiplexing/multiplexing means, and
• wherein said demultiplexing/multiplexing means comprises a diffraction grating formed on said end face of said optical fiber and positioned at an angle, relative to the optical axis of said optical fiber.

An optical fiber apparatus comprising:

• an optical fiber having an optical axial direction and an end face;
• and
• demultiplexing/multiplexing means provided or formed directly on at least said end face of said optical fiber,
• wherein said demultiplexing/multiplexing means demultiplexes or multiplexes a light wave of at least a wavelength with a wavelength spectrum that is determined by a resolving power of said demultiplexing/multiplexing means,
• wherein said demultiplexing/multiplexing means comprises:
• (1) a reflective surface formed on an end face of said optical fiber for reflecting and deflecting light transmitted through said optical fiber at an angle of 45°, relative to an optical axis of said optical fiber;
• and
• (2) an optical filter array, including a plurality of optical filters for selecting light at different wavelengths, respectively, provided on a side surface of said optical fiber, and
• wherein reflected light is guided from said reflective surface to said optical filter array.

An optical fiber apparatus comprising:

• an optical fiber having an optical axial direction and an end face;
• and
• demultiplexing/multiplexing means provided or formed directly on at least said end face of said optical fiber,
• wherein said demultiplexing/multiplexing means demultiplexes or multiplexes a light wave of at least a wavelength with a wavelength spectrum that is determined by a resolving power of said demultiplexing/multiplexing means, and
• wherein said demultiplexing/multiplexing means comprises:
• (1) a core-extending portion provided on an end face of said optical fiber, said core-extending portion having a refractive index different from a refractive index of a core of said optical fiber;
• and
• (2) a diffraction grating formed at an interface between said core-extending portion and said core of said optical fiber.

An optical fiber apparatus comprising:

• an optical fiber having an optical axial direction and an end face;
• and
• demultiplexing/multiplexing means provided or formed directly on at least said end face of said optical fiber,
• wherein said demultiplexing/multiplexing means demultiplexes or multiplexes a light wave of at least a wavelength with a wavelength spectrum that is determined by a resolving power of said demultiplexing/multiplexing means, and
• wherein said demultiplexing/multiplexing means comprises a deflecting optical switch for deflecting a light wave in different directions depending on its wavelength or incident timing, said deflecting optical switch comprising control means for varying a deflection function of said deflecting optical switch.

An optical fiber apparatus comprising:

• an optical fiber having an optical axial direction and an end face;
• and
• demultiplexing/multiplexing means provided or formed directly on at least said end face of said optical fiber,
• wherein said demultiplexing/multiplexing means demultiplexes or multiplexes a light wave of at least a wavelength with a wavelength spectrum that is determined by a resolving power of said demultiplexing/multiplexing means, and
• wherein said demultiplexing/multiplexing means is provided or formed on said end face and a side surface of said optical fiber.

An optical fiber apparatus comprising:

• an optical fiber having an optical axial direction and an end face;
• and
• demultiplexing/multiplexing means provided or formed directly on at least said end face of said optical fiber,
• wherein said demultiplexing/multiplexing means demultiplexes or multiplexes a light wave of at least a wavelength with a wavelength spectrum that is determined by a resolving power of said demultiplexing/multiplexing means, and
• wherein said optical fiber has a core and a clad, and the core is removed at an end portion of said optical fiber with the clad being partially left, and wherein said demultiplexing/multiplexing means is provided on said partially left clad.

An optical fiber apparatus comprising:

• an optical fiber having an optical axial direction and an end face;
• and
• demultiplexing/multiplexing means provided or formed directly on at least said end face of said optical fiber,
• wherein said demultiplexing/multiplexing means demultiplexes or multiplexes a light wave of at least a wavelength with a wavelength spectrum that is determined by a resolving power of said demultiplexing/multiplexing means, and
• wherein said optical fiber has a core and a clad, and the core is removed at an end portion of said optical fiber with the clad being entirely left, and wherein said demultiplexing/multiplexing means is provided in said entirely left clad.

An optical fiber apparatus comprising:

• an optical fiber having an optical axial direction and an end face;
• and
• demultiplexing/multiplexing means provided or formed directly on at least said end face of said optical fiber,
• wherein said demultiplexing/multiplexing means demultiplexes or multiplexes a light wave of at least a wavelength with a wavelength spectrum that is determined by a resolving power of said demultiplexing/multiplexing means, and
• wherein at least said demultiplexing/multiplexing means is integrally molded with an end portion of said optical fiber.

An optical detecting apparatus comprising:

• optical detecting means including a plurality of optical detectors;
• and
• demultiplexing/multiplexing means provided or formed directly on at least a light-receiving surface of said optical detecting means for demultiplexing or multiplexing a plurality of light waves at different wavelengths with wavelength spectra that are determined by a resolving power of said demultiplexing/multiplexing means,
• wherein said demultiplexing/multiplexing means comprises a Fabry-Perot etalon whose optical length varies along a direction approximately perpendicular to the optical-axial direction of said optical fiber.

An optical transmission system comprising:

• an optical fiber having an end face;
• and
• demultiplexing/multiplexing means provided or formed directly on said end face of said optical fiber for demultiplexing or multiplexing wavelength multiplexed optical signals having a wavelength interval and a wavelength width, with wavelength spectra that are determined by a resolving power of said demultiplexing/multiplexing means,
• wherein wavelength multiplexed optical signals are capable of being transmitted through said optical fiber,
• wherein the wavelength interval of the wavelength multiplexed optical signals is Δλ1, and the wavelength width occupied by each optical signal is Δλ2, which is not larger than Δλ1,
• wherein said demultiplexing/multiplexing means includes (1) a light entrance surface for receiving light from said optical fiber and (2) a light emergence surface, and
• wherein said demultiplexing/multiplexing means is set such that demultiplexed optical signals of different wavelengths at least partially emerge at different positions of said light emergence surface, respectively.

An optical transmission system comprising:

• a light transmission line;
• optical detecting means including a plurality of optical detectors;
• and
• demultiplexing/multiplexing means provided or formed directly on the light receiving surface of said optical detecting means, for demultiplexing or multiplexing wavelength multiplexed optical signals having a wavelength interval and a wavelength width, with wavelength spectra that are determined by a resolving power of said demultiplexing/multiplexing means,
• wherein wavelength multiplexed optical signals are capable of being transmitted through said transmission line and received by said optical detecting means,
• wherein the wavelength interval of the wavelength multiplexed optical signals is Δλ1, and the wavelength width occupied by each optical signal is Δλ2, which is not larger than Δλ1, and
• wherein said demultiplexing/multiplexing means comprises a Fabry-Perot etalon whose optical length varies along a direction approximately perpendicular to the optical-axial direction of said optical fiber.