Optical waveguides – Having nonlinear property
Patent
1996-12-11
1998-04-28
Lee, John D.
Optical waveguides
Having nonlinear property
359332, 359576, G02B 610, G02F 135
Patent
active
057456291
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to an optical device having a multi-layer structure consisting of optical material films and a method of producing the device, and more specifically to a method of producing a waveguide for a nonlinear optical device having a periodically oriented structure and a grating having a periodic refractive index distribution, by use of film forming and film laminating of an optical material.
It is known that a quasi phase matching (QPM) method is useful for various electro-optical devices using nonlinear interactions of optical waves, such as a wavelength conversion device and the like. A QPM device is formed of a ferroelectric crystal such as LiNbO.sub.3 or LiTaO.sub.3, which is a nonlinear optical material. In the QPM device, a periodic domain structure having periodic inversion of the sign of the nonlinear coefficient is introduced. To introduce the periodic domain structure in the ferroelectric crystal, a method of applying an electric field or irradiating an electron beam is used.
However, the ferroelectric crystal is expensive, and it is difficult to machine the ferroelectric crystal to have a fine structure. For these reasons, researches on organic nonlinear optical materials and optical devices using organic nonlinear materials have recently been active. To achieve an excellent nonlinear optical property for an organic optical device, for example, a polymer film having the second order nonlinear optical dye moieties is used. The polymer film is poled by applying an electric field at a predetermined temperature.
In details, a polymer film waveguide is formed on a substrate, for example, by a spin-coat method. The spin-coated polymer film is applied for an electric field at about glass transition temperature by corona-poling apparatus to have a periodic domain structure. This polymer film waveguide can be used for a second harmonic generation (SHG) device. For efficient wavelength conversion, it is definitely important to meet a phase matching condition in the waveguide.
However, it is not easy to form a periodic domain structure in a polymer film waveguide corresponding to a coherence length by electric field poling. Therefore, the efficiency of wavelength conversion is still small at present. The poled polymer film poled by the electric field has also such a problem that relaxation of aligned molecules occurs after fabrication.
On the other hand, recently, wide-band and low-loss optical fibers using organic polymer materials (hereinafter, these fibers will be described as plastic fibers) are manufactured. Various researches for applying plastic fibers to optical fiber communication networks are active. Since the low-loss wavelength range of the plastic optical fiber is, for example, 650 nm in a visible wavelength region, it is desired to develop optical devices such as an optical amplifier for a plastic optical fiber system in a visible wavelength region, a novel optical fiber oscillator and the like.
The fiber-type optical amplifier has many features such as it is able to amplify a light beam by light excitation with high efficiency and high gain in a wide band, and to reveal a good matching with a fiber system. For example, by use of a silica-based material, rare-earth doped fiber amplifiers, which exhibit optical amplifying properties in an infrared region, have been developed. However, optical fiber oscillators (i.e., lasers), or optical fiber amplifiers, which can be used in a visible wavelength region, still have not been utilized.
Some of fluorescent organic dyes, for example, rhodamine dye, can exhibit excellent optical amplification property in a visible region. Since plastic fibers have low glass transition temperatures, it is easy to incorporate the organic dye into the plastic fiber. Therefore, by incorporating organic dye which is conformable to a necessary wavelength region and have a large stimulated emission area, it is theoretically able to achieve high efficient optical oscillation and optical amplification in every range within a visible region.
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REFERENCES:
patent: 4243398 (1981-01-01), Nomura et al.
patent: 4913844 (1990-04-01), Demartino
patent: 5119228 (1992-06-01), Fang
patent: 5217792 (1993-06-01), Chidsey et al.
patent: 5289308 (1994-02-01), Horsthuis et al.
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