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US 5,080,462 AGranted
Optical wavelength converter device and optical wavelength converter system
AssigneeFuji Photo Film Co., Ltd.
InventorChiaki Goto
Life of this patent
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Abstract
An optical wavelength converter device is of the fiber type including a cladding and a core surrounded by the cladding, the cladding having a lower refractive index than the refractive index of the core. The optical wavelength converter device serves to convert a fundamental wave into a secondary harmonic wave. The cladding has an exit end surface shaped for converting the wavefront of a wavelength-converted wave from the conical wavefront into a planar or spherical wavefront. A optical wavelength converter system comprises such an optical wavelength converter device and an optical device for diffractively or refractively converting the wavefront of the wavelength-converted wave from a conical wavefront into a planar or spherical wavefront.
Claims8
An optical wavelength converter device comprising an optical fiber including:
- i) a cladding having a first refractive index;
- ii) a core of a nonlinear optical material disposed in said cladding and having a second refractive index higher than said first refractive index, whereby said optical fiber converts the wavelength of a fundamental wave introduced into said core and radiates a wavelength-converted wave into said cladding;
- iii) said cladding having an exit end surface for emitting the wavelength-converted wave, said exit end surface having a conical or substantially conical shape for converting the conical wavefront of said wavelength-converted wave into a planar or spherical wavefront;
- iv) the material of said cladding and the diameter of said core being selected such that the wavelength dependencies .differential..theta./.differential..lambda., .differential.n/.differential..lambda. of a phase matching angle .theta.o and a refractive index n of the cladding with respect to the wavelength-converted wave are related to each other as follows:
- ##EQU81## where .lambda. is the wavelength of the wavelength converted wave;
- and v) the difference between the left- and right-hand sides of the above equation falling within a range smaller than sin.sup.-1 (.lambda./2Dn), where D is the effective diameter of the wavelength-converted wave.
3 more elements
An optical wavelength converter system comprising:
- i) an optical fiber including a cladding having a first refractive index, and a core of a nonlinear optical material disposed in said cladding and having a second refractive index higher than said first refractive index, whereby said optical fiber converts the wavelength of a fundamental wave introduced into said core and radiates a wavelength-converted wave into said cladding, said cladding having an exit end surface for emitting the wavelength-converted wave;
- ii) an optical device disposed in a position to receive the wavelength-converted wave emitted from the said exit end surface, for diffractively converting the wavefront of the wavelength-converted wave from a conical wavefront into a planar or spherical wavefront;
- and
- iii) the material of said cladding and the diameter of said core being selected such that the wavelength dependency .differential..theta.A/.differential..lambda. of an angle .theta.A at which the wavelength-converted wave is emitted from the cladding exit end surface approximates .theta.A/.lambda. within an error range smaller than sin.sup.-1 (.lambda./2D) where .lambda. is the wavelength of the wavelength-converted wave, and D is the effective diameter of the wavelength-converted wave.
1 more element
An optical wavelength converter system comprising:
- i) an optical fiber including a cladding having a first refractive index, and a core of a nonlinear optical material disposed in said cladding and having a second refractive index higher than said first refractive index, whereby said optical fiber converts the wavelength of a fundamental wave introduced into said core and radiates a wavelength-converted wave into said cladding, said cladding having an exit end surface for emitting the wavelength-converted wave;
- ii) an optical device disposed in a position to receive the wavelength-converted wave emitted from the said exit end surface, for refractively converting the wavefront of the wavelength-converted wave from a conical wavefront into a planar or spherical wavefront;
- and
- iii) the material of said cladding and the diameter of said core being selected such that the wavelength dependency .differential..theta.A/.differential..lambda. [.degree./nm] of an angle .theta.A at which the wavelength-converted wave is emitted from the cladding exit end surface falls in the range:
- ##EQU82## where .lambda. is the wavelength of the wavelength-converted wave.
2 more elements
An optical wavelength converter system comprising:
- i) an optical fiber including a cladding having a first refractive index, and a core of a nonlinear optical material disposed in said cladding and having a second refractive index higher than said first refractive index, whereby said optical fiber converts the wavelength of a fundamental wave introduced into said core and radiates a wavelength-converted wave into said cladding, said cladding having an exit end surface for emitting the wavelength-converted wave;
- and
- ii) a reflective optical device for converting the wavefront of the wavelength-converted wave from a conical wavefront into a planar wavefront, said reflective optical device having a central axis aligned with the center of said core of the optical fiber, said reflective optical device also having a first conical refection surface for reflecting the wavelength-converted wave emitted from the cladding exit end surface of the optical fiber, toward said central axis, and a second conical reflecting surface for reflecting the wavelength-converted wave, which has been reflected by said first reflecting surface, in a direction away from the optical fiber.
An optical wavelength converter system comprising:
- i) an optical fiber including a cladding having a first refractive index, and a core of a nonlinear optical material disposed in said cladding and having a second refractive index higher than said first refractive index, whereby said optical fiber converts the wavelength of a fundamental wave introduced into said core and radiates a wavelength-converted wave into said cladding, said cladding having an exit end surface for emitting the wavelength-converted wave;
- and
- ii) a reflective optical device for converting the wavefront of the wavelength-converted wave from a conical wavefront into a spherical wavefront, said reflective optical device having a central axis aligned with the center of said core of the optical fiber, said reflective optical device also having a first substantially conical reflecting surface for reflecting the wavelength-converted wave emitted from the cladding exit end surface of the optical fiber, toward said central axis, and a second substantially conical reflecting surface for reflecting the wavelength-converted wave, which has been reflected by said first reflecting surface, in a direction away from the optical fiber, at least one of said reflecting surfaces having a curvature.
An optical wavelength converter system comprising:
- i) an optical fiber including a cladding having a first refractive index, and a core of a nonlinear optical material disposed in said cladding and having a second refractive index higher than said first refractive index, whereby said optical fiber converts the wavelength of a fundamental wave introduced into said core and radiates a wavelength-converted wave into said cladding, said cladding having an exit end surface for emitting the wavelength-converted wave;
- ii) refractive and diffractive optical devices positioned to receive the wavelength-converted wave emitted from the cladding exit end surface of said optical fiber, for respectively refracting and diffracting the wavelength-converted wave to convert the conical wavefront thereof refractively and diffractively into a planar or spherical wavefront;
- and
- iii) said optical devices being separate from said optical fiber, and arranged to satisfy the equation:
- ##EQU83## where .differential..theta.t/.differential..lambda. is the wavelength dependency of the total angle .theta.t at which the wavelength-converted wave is deflected by the optical devices, and .differential..theta.A/.differential..lambda. is the wavelength dependency of the angle .theta.A at which the wavelength-converted wave is emitted from the cladding exit end surface.
2 more elements
An optical wavelength converter system comprising:
- i) an optical fiber including a cladding having a first refractive index, and a core of a nonlinear optical material disposed in said cladding and having a second refractive index higher than said first refractive index, whereby said optical fiber converts the wavelength of a fundamental wave introduced into said core and radiates a wavelength-converted wave into said cladding, said cladding having an exit end surface for emitting the wavelength-converted wave;
- ii) refractive and diffractive optical devices positioned to receive the wavelength-converted wave emitted from the cladding exit end surface of said optical fiber, for respectively refracting and diffracting the wavelength-converted wave to convert the conical wavefront thereof refractively and diffractively into a planar or spherical wavefront, and
- iii) one of said optical devices being formed directly on the cladding exit end surface, and arranged to satisfy the equation:
- ##EQU84## where .differential..theta.t/.differential..lambda. is the wavelength dependency of the total angle .theta.t at which the wavelength-converted wave is deflected by the optical devices, n is the refractive index of the cladding, .theta.o is the phase matching angle, and .differential..theta.o/.differential..lambda. is the wavelength dependency of the phase matching angle .theta.o.
1 more element
Dependencies are inferred from the claim text.