WO2003100926A1

WO2003100926A1 - Cr4+DOPED CRYSTAL STRIP-LOADED OPTICAL WAVEGUIDE AMPLIFIERS FOR BROADBAND OPTICAL AMPLIFICATION AROUND 1310 NM

Info

Publication number: WO2003100926A1
Application number: PCT/US2003/015667
Authority: WO
Inventors: Renyuan Gao; Anthony F. Garito
Original assignee: Photon-X, Inc.
Priority date: 2002-05-20
Filing date: 2003-05-20
Publication date: 2003-12-04
Also published as: AU2003239498A1

Abstract

The present invention discloses an optical device, comprising a Cr4+ Doped crystal substrate and at least one optically transparent strop disposed on the substrate, wherein the at least one optically transparent strip has a higher refractive index than the substrate.

Description

Cr⁴⁺ DOPED CRYSTAL STRIP-LOADED OPTICAL WAVEGUIDE AMPLIFIERS FOR BROADBAND OPTICAL AMPLIFICATION AROUND 1310 NM

CROSS-REFERENCE TO RELATED APPLICATION

[001] This application claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Provisional Application 60/381 ,854 filed May 20, 2002, the contents of which are herein incorporated by reference.

FIELD OF THE INVENTION

[002] Embodiments consistent with the present invention relate to planar waveguides and planar waveguide optical amplifiers operating in the 1200-1600 nm wavelength window, including the 1310 nm wavelength. The present invention is also related to optical devices comprising the planar waveguide.

BACKGROUND OF THE INVENTION

[003] The advent of optical amplifier and dense wavelength division multiplexing (DWDM) has revolutionized the telecommunications industry by replacing electronic data regenerators between optical fiber transmission links with less expensive, data format "transparent," optical amplification devices. For example, silica based erbium doped fiber amplifier (EDFA), operating in the 1530-1610 nm wavelength window, can be highly efficient and cost-effective and has been the predominant optical amplification device in long-haul, ultra-long haul, and transoceanic networks. Because of the tremendous success of the EDFA, most of the long-haul, ultra-long haul, and transoceanic networks use signal wavelength channels in the 1530-1610 nm erbium amplification window. However, many installed optical networks operate at the second loss window of silica optical fibers around 1310 nm, for example, cable television (CATV) distribution systems. In addition, the newly emerging metropolitan optical networks and optical Ethernet networks are increasingly being operated around 1310 nm due to more cost effective components, such as vertical cavity surface emission lasers (VCSELs) and 1310 nm transponders and transceivers. In order for these emerging technologies to continue developing into efficient and cost- effective solutions for telecommunications, as well as for the existing 1310 nm optical systems to improve operation efficiency, it is of great importance to have an efficient and cost-effective 1310 nm optical amplification device.

[004] Several different types of technologies have been attempted and evaluated in the past several years, including semiconductor optical amplifiers, Raman fiber amplifiers, and fiber amplifiers doped with Nd, Pr, and/or Dy. Due to various performance and manufacturing problems, such as low efficiency, high noise figure, and/or poor reliability, none of the above mentioned technologies have been widely used in optical networks.

[005] Among the various approaches for 1310 nm amplification, Neodymium (Nd), Praseodymium (Pr), and/or Dysprosium (Dy) doped fiber amplifiers have received the most attention, with Pr and Dy doped amplifiers being more promising because of their higher efficiency compared with Nd. However, most of the known 1310 nm Pr and Dy doped amplifiers employ halide such as fluoride, chalcogenide, chalcohalide, and arsenic glasses. These glasses are then fabricated into optical fiber preforms and then drawn into amplification optical fibers. Alternatively, planar waveguides can be formed using a doped fluoride glass substrate. In either case, the known technologies rely on fluoride, halide, chalcogenide, chalcohalide, selenide and arsenic glasses. These glasses have the problem of being extremely mechanically fragile and sometimes moisture sensitive, thus making device reliability a severe issue. Furthermore, devices based on discrete fiber components such as Pr or Dy doped fluoride fibers can be difficult, time-consuming and costly to fabricate into amplifier device modules due to the numerous splices of connecting various components in the module, such as the pump/signal coupler and tap coupler. It would be beneficial to have an easy to manufacture, integrated 1310 nm optical amplifier.

[006] It is well known that planar waveguide provides a platform for achieving optical components integration. Planar waveguides based optical amplifiers have been developed in silica-based glass primarily for 1550 nm wavelength amplification. The optical gain medium can be formed by various processes, such as Chemical Vapor Depositon (CVD), ion exchange, photolithography, flame-hydrolysis, and reactive ion-etching, and the resulting gain medium is a straight line or curved rare earth doped waveguide. Such rare earth doped waveguide is pumped by pump lasers with various wavelengths. The pump lasers are combined with the signal (e.g., 1535 nm -1610 nm for erbium doped channel waveguide) by a directional coupler. Optical isolators are inserted into the optical path for preventing back-reflected signal amplification in the rare earth doped channel waveguides.

[007] It is known to use rare earth doped glass waveguides. In order to form glass channel waveguides, glass films need to be formed for the undercladding, core, and overcladding layers. Typical fabrication processes of glass films include, for example, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), and flamehydrolysis. These fabrication processes require complex equipments and can be time-consuming and costly. Further, these processes are developed only for silica based glass, which is only compatible with erbium amplifiers operating in the 1550 nm wavelength window. Therefore, it is desirable to have a waveguide amplifier material system and fabrication process that can be versatile, reliable and cost- effective. The present invention discloses, in one embodiment, a planar waveguide optical amplifier operating in the 1200 nm -1600 nm wavelength window covering the 1310 nm wavelength based on a rib waveguide configuration.

[008] The present invention can overcome one or more of the above- described problems or disadvantages associated with the prior art.

SUMMARY OF THE INVENTION

[009] The present invention discloses optical devices, such as waveguides and optical waveguide amplifiers, comprising a Chromium (Cr⁴⁺) doped crystal substrate and at least one optically transparent strip disposed on the substrate, wherein the optically transparent strip has a higher refractive index than the Cr⁴⁺ doped crystal substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

[010] In the drawings: [011] FIG. 1 is a schematic illustration of the strip-loaded amplification waveguide cross-section.

[012] FIG. 2 is a schematic illustration of the fabrication process of forming the strip-loaded waveguide.

[013] FIG. 3 is a measured emission spectrum of the Cr⁴⁺:YAG (Y₃Al₅θι₂, yttrium aluminum garnet) crystal.

[014] FIG. 4 is a schematic illustration of the configuration of a 1.3μm

waveguide amplifier.

[015] FIG. 5 shows a curved waveguide amplifier for 1310 nm broadband amplification.

[016] FIG. 6 shows the 1310 nm signal mode distribution in the cross- section of a Cr⁴⁺ doped crystal strip-loaded amplifier.

[017] FIG. 7 shows the 1310 nm pump mode distribution in the cross- section of a Cr⁴⁺ doped crystal strip-loaded amplifier.

DETAILED DESCRIPTION OF THE INVENTION

[018] In the following description, reference is made to the accompanying drawings that form a part thereof, and in which is shown by way of illustration specific exemplary embodiments in which the invention can be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments can be utilized and that changes can be made without departing from the scope of the present invention. [019] Disclosed herein is an optical device, such as a waveguide and an optical waveguide amplifier, comprising a Cr⁴⁺ doped crystal substrate and at least one optically transparent strip disposed on the substrate, wherein the at least one strip has a higher refractive index than that of the Cr⁴⁺ doped crystal substrate.

[020] The Cr⁴⁺ doped crystal can be chosen, for example, from Cr⁴⁺ doped into the following crystals: Ca₂GeO₄; Li₂MgSiO₄; Li₂ZnSiO₄; Li₂CaGeO₄; Li₂CaSiO₄; Li₂CdGeO₄; Li₂CdSiO₄; Li₂MgGeO₄; Li₂ZnGeO₄; Li₂ZnSiO₄; Mg₂GeO₄; LiGaSiO₄; Y₂SiO₅; Ca₂AI₂SiO₇; Y₃AI₅O₁₂; Zn₂SiO₄; MgSiO₄; LiAIO₂; LiGaO₂; LiAIO₂; Lu₃AI₅O₁₂; Y₃AI₅O₁₂ (YAG); Y₃Ga₅O₁₂; Gd₃Ga₅Oι₂; Ti:AI₂O₃; Ca₂SiO₄; LiAIGeO ; CaMgSiO₄; LiScGeO4; LilnGeO₄; and LiScGeO₄.

[021] In one embodiment of the invention, the Cr⁴⁺ doped crystal may be co-doped with another ion, such as Yb³⁺.

[022] The optically transparent strip is made of at least one material chosen from glasses and polymers. In addition, the optically transparent strip has a refractive index ranging, for example, from about 1.5 to about 5, further from about 1.5 to about 2.5, and even further from about 1.8 to 2.0.

[023] The polymers can be chosen, for example, from hydrocarbon polymers, nanoporous random glassy polymers, and polymer nanocomposites.

[024] As disclosed herein, the hydrocarbon polymers and the nanoporous random glassy polymers are chosen, for example, from polymers, copolymers, and terpolymers comprising at least one halogenated monomer represented by one of the following formulas:

[026] wherein R¹, R², R³, R⁴, and R⁵, which may be identical or different, are each chosen from linear and branched hydrocarbon-based chains, possibly forming at least one carbon-based ring, being saturated or unsaturated, wherein at least one hydrogen atom of the hydrocarbon-based chains may be halogenated; a halogenated alkyl, a halogenated aryl, a halogenated cyclic alky, a halogenated alkenyl, a halogenated alkylene ether, a halogenated siloxane, a halogenated ether, a halogenated polyether, a halogenated thioether, a halogenated silylene, and a halogenated silazane; Y₁ and Y₂, which may be identical or different, are each chosen from H, F, CI, and Br atoms. Y₃ is chosen from H, F, CI, and Br atoms, CF₃, and CH₃.

[027] Alternatively, the hydrocarbon polymers and the nanoporous random glassy polymers may comprise a condensation product made from the monomers listed below: [028] HO-R-OH + NCO-R'-NCO; and

[029] HO-R-OH + Ary¹-Ary²,

[030] wherein R and R', which may be identical or different, are each chosen from halogenated alkylene, halogenated siloxane, halogenated ether, halogenated silylene, halogenated arylene, halogenated polyether, and halogenated cyclic alkylene; Ary¹ and Ary², which may be identical or different, are each chosen from halogenated aryls and halogenated alkyl aryls.

[031] Ary as used herein, is defined as being a saturated, or unsaturated, halogenated aryl, or a halogenated alkyl aryl group.

[032] Alternatively, the hydrocarbon polymers and the nanoporous random glassy polymers are chosen from halogenated cyclic olefin polymers, halogenated cyclic olefin copolymers, halogenated polycyclic polymers, halogenated polyimides, halogenated polyether ether ketones, halogenated epoxy resins, halogenated polysulfones, and halogenated polycarbonates.

[033] In one embodiment, the halogenated aryl, alkyl, alkylene, alkylene ether, alkoxy, siloxane, ether, polyether, thioether, silylene, and silazane groups are at least partially halogenated, meaning that at least one hydrogen in the group has been replaced by a halogen. In another embodiment, at least one hydrogen in the group may be replaced by fluorine. Alternatively, these aryl, alkyl, alkylene, alkylene ether, alkoxy, siloxane, ether, polyether, thioether, silylene, and silazane groups may be completely halogenated, meaning that each hydrogen of the group has been replaced by a halogen. In an exemplary embodiment, the aryl, alkyl, alkylene, alkylene ether, alkoxy, siloxane, ether, polyether, thioether, silylene, and silazane groups may be completely fluorinated, meaning that each hydrogen has been replaced by fluorine. Furthermore, the alkyl and alkylene groups may include between 1 and 12 carbon atoms.

[034] The hydrocarbon polymers and the nanoporous random glassy polymers may also be chosen from, for example, halogenated polymers containing functional groups such as phosphinates, phosphates, carboxylates, silanes, siloxanes, sulfides, including POOH, POSH, PSSH, OH, SO H, SO R, SO₄R, COOH, NH₂, NHR, NR₂, CONH₂, and NH-NH₂, wherein R is chosen from aryls, alkyls, alkylenes, siloxanes, silanes, ethers, polyethers, thioethers, silylenes, and silazanes. Further, the hydrocarbon polymers and the nanoporous random glassy polymers may also be chosen from, for example, homopolymers and copolymers of vinyl, acrylate, methacrylate, vinyl aromatic, vinyl esters, alpha beta unsaturated acid esters, unsaturated carboxylic acid esters, vinyl chloride, vinylidene chloride, and diene monomers. Even further, the hydrocarbon polymers and the nanoporous random glassy polymers may be chosen from, for example, hydrogen-containing fluoroelastomers, hydrogen- containing perfluoroelastomers, hydrogen containing fluoroplastics, perfluorothermoplastics, and cross-linked halogenated polymers.

[035] Examples the hydrocarbon polymers and the nanoporous random glassy polymers include: poly[2,2-bistrifluoromethyl-4,5-difluoro-1 ,3-dioxole-co- tetrafluoroethylene], poly[2,2-bisperfluoroalkyl-4,5-difluoro-1 ,3-dioxole-co- tetrafluoroethylene], poly[2,3-(perfluoroalkenyl) perfluorotetrahydrofuran], poly[2,2,4-trifluoro-5-trifluoromethoxy-1 ,3-dioxole-co-tetrafluoroethylene], poly(pentafluorostyrene), fluorinated polyimide, fluorinated polymethylmethacrylate, polyfluoroacrylates, polyfluorostyrene, fluorinated polycarbonates, fluorinated poly (N-vinylcarbazole), fluorinated acrylonitrile- styrene copolymer, fluorinated Nafion®, fluorinated poly(phenylenevinylene), perfluoro-polycyclic polymers, polymers of fluorinated cyclic olefins, and copolymers of fluorinated cyclic olefins.

[036] In addition, the hydrocarbon polymers and the nanoporous random glassy polymers may also be chosen from, for example, polymethylmethacrylates, polystyrenes, polycarbonates, polyimides, epoxy resins, cyclic olefin copolymers, cyclic olefin polymers, acrylate polymers, PET, polyphenylene vinylene, polyether ether ketone, poly (N-vinylcarbazole), acrylonitrile-styrene copolymer, and poly(phenylenevinylene).

[037] As disclosed herein, the nanoporous random glassy polymers can also be chosen, for example, from those disclosed in U.S. Application No. 10/ 359,725, which is incorporated herein by reference.

[038] As disclosed herein, the polymer nanocomposites comprise a host matrix and a plurality of nanoparticles within the host matrix. The host matrix comprises at least one polymer chosen from the hydrocarbon polymers and the nanoporous random glassy polymers as disclosed above. The host matrix may comprise a combination of one or more different hydrocarbon polymers, such as halogenated polymers, for example, fluoropolymers, blended together. [039] Nanoparticles are particles of a material that have a size measured on a nanometer scale. Generally, nanoparticles are larger than a cluster (which might be only a few hundred atoms in some cases), but with a relatively large surface area-to-bulk volume ratio. While most nanoparticles have a size from about 10 nm to about 500 nm, the term nanoparticles can cover particles having sizes that fall outside of this range. For example, particles having a size as small as about 1 nm and as large as about 1x10³ nm could still be considered nanoparticles.

[040] Nanoparticles can be made from a wide array of materials. Among these materials examples include metal, glass, ceramics, refractory materials, dielectric materials, carbon or graphite, natural and synthetic polymers including plastics and elastomers, dyes, ion, alloy, compound, composite, or complex of transition metal elements, rare-earth metal elements, group VA elements, semiconductors, alkaline earth metal elements, alkali metal elements, group MIA elements, and group IVA elements or polymers and dyes.

[041] Further, the materials may be crystalline, amorphous, or mixtures, or combinations of such structures. Nanoparticles may be bare, coated, bare core-shell, coated core-shell. In addition, nanoparticles themselves may be considered a nanoparticle matrix, which may comprise a wide array of materials, single elements, mixtures of elements, stoichiometric or non-stoichiometric compounds.

[042] A plurality of nanoparticles may include an outer coating layer, which at least partially coats nanoparticles and can inhibit their agglomeration. Suitable coating materials may have a tail group, which is compatible with the host matrix, and a head group, that could attach to the surface of the particles either through physical adsorption or chemical reaction. The nanoparticles disclosed herein may be doped with an effective amount of dopant material. An effective amount is that amount necessary to achieve the desired result. The nanoparticles of doped glassy media, single crystal, or polymer are embedded in the host matrix material. The active nanoparticles may be randomly and uniformly distributed. The nano-particles of rare-earth doped, or co-doped, glasses, single crystals, organic dyes, or polymers are embedded in the polymer core material.

[043] The nanoparticles may comprise at least one semiconductor material chosen, for example, from Si, PbS, Ge, GaP, GaAs, InP, InAs, InSb, PbSe, and PbTe. In addition, the nanoparticles may comprise at least one dielectric material chosen, for example, from NaCI, TiO₂, SiO₂, B₂O₃, Ge₂O₃, ZnO₂, LiNbO₃, and BaTiO₃.

[044] The material that forms the nanoparticle may be in the form of an ion, alloy, compound, or complex, and may comprise at least one of the following: oxide, phosphate, halophosphate, phosphinate, arsenate, sulfate, borate, aluminate, gallate, silicate, germanate, vanadate, niobate, tantalite, tungstate, molybdate, alkalihalogenate, halogenide, nitride, selenide, sulfide, sulfoselenide, tetrafluoroborate, hexafluorophosphate, phosphonate, and oxysulfide. [045] In addition, the polymer nanocomposites can be chosen, for example, from those disclosed in U.S. Application No. 10/367,683, which is incorporated herein by reference.

[046] In one embodiment, a Cr⁴⁺ doped crystal wafer, such as a Cr⁴⁺:Ca₂GeO₄ crystal wafer, is used with waveguide confinement and a rib structure of the polymer strip is formed on the surface of the wafer film. Figure 1 shows the rib waveguide amplification waveguide cross-section. The wafer is fabricated by growing a single crystal with diameter of 1-10 centimeters. The single crystal rod is cut into wafer disks with thickness of 0.5-3 millimeters by a diamond saw. The top surface of the crystal is then polished by wafer polishing techniques.

[047] The waveguide structure can be chosen from, for example, three forms:

[048] (1 ) the polymer strip core is on the Cr⁴⁺ doped crystal substrate, wherein the waveguide overcladding is air;

[049] (2) the polymer strip core is on the Cr⁴⁺ doped crystal substrate, wherein the waveguide overcladding is chosen from other polymer materials; and

[050] (3) the polymer strip core is on the Cr⁴⁺ doped crystal substrate, wherein the waveguide overcladding is air or chosen from other polymer materials. In addition, there is a thin layer, for example, 0.5-3 micrometers, of Cr⁴⁺ doped crystal with elevated refractive index between the polymer strip and the Cr⁴⁺ doped crystal substrate. This layer can be realized by, for example, ion- exchange. [051] Also disclosed herein is a fabrication process of forming the strip- loaded waveguide, for example, as shown in Figure 2. In one embodiment, a metal layer of 10-100 nanometers is deposited on top of the Cr⁴⁺ doped crystal wafer by evaporation or sputtering. The metal is chosen, for example, from aluminum and gold. A photoresist layer with a thickness of 100-500 nm is deposited on top of the metal film by spin-coating. The Cr⁴⁺ doped crystal wafer subsequently undergoes photolithography, metal etching and reactive ion etching to form the waveguide patterns on the wafer. The width of the rib structure is ranging from 1 to 10 micrometers. The Cr⁴⁺ doped crystal is chosen, for example, from Cr⁴⁺:YAG, Cr⁴⁺:Ca₂GeO₄, and Cr⁴⁺:Mg₂SiO₄ crystals. The Cr⁴⁺ doped crystal wafer then undergoes spin-coating process, which applies a polymer or polymer nanocomposite coating on top of it. The refractive index of the coating is higher than that of the underlying wafer. The thickness of the coating ranges, for example, from 1 to 10 micrometers.

[052] As shown in Figure 3, the emission band of the Cr⁴⁺:YAG crystal with 980 nm pumping spans from 1200 nm to 1600 nm.

[053] In Figure 4, a schematic illustration of the configuration of a 1.3μm

waveguide amplifier is shown. The 1.3μm signal is coupled with pump signal

through a wavelength division multiplexer (WDM) and injected into the amplification waveguide channel. Optical isolators are placed at the input and the output end of the waveguide amplifier to prevent back reflected signal light. The pump wavelength for, for example, the Cr⁴⁺:YAG rib waveguide amplifier are ranging from 900 nm to 1200 nm. Therefore the readily available 980nm diode laser can be used.

[054] Figure 5 shows a curved waveguide amplifier for 1310 nm broadband amplification. The curved waveguide allows long amplification waveguide path length in a small area. A directional WDM coupler is placed on the waveguide chip to combine the signal and pump.

[055] FIG. 6 shows the 1310 nm signal mode distribution in the cross- section of a Cr⁴⁺ doped crystal strip-loaded amplifier.

[056] FIG. 7 shows the 1310 nm pump mode distribution in the cross- section of a Cr⁴⁺ doped crystal strip-loaded amplifier.

Claims

WHAT IS CLAIMED IS:

1. An optical device, comprising a Cr⁴⁺ doped crystal substrate and at least one optically transparent strip disposed on said substrate, wherein said at least one optically transparent strip has a higher refractive index than said substrate.

2. The optical device of Claim 1 , wherein the Cr⁴⁺ doped crystal is chosen from: Cr⁴⁺:Ca₂GeO₄; Cr⁴⁺:Li₂MgSiO₄; Cr⁴⁺:Li₂ZnSiO₄; Cr⁴⁺:Li₂CaGeO₄; Cr⁴⁺:Li₂CaSiO₄; Cr⁴⁺:Li₂CdGeO₄; Cr⁴⁺:Li₂CdSiO₄; Cr⁴⁺:Li₂MgGeO₄; Cr⁴⁺:Li₂ZnGeO₄; Cr⁴⁺:Li₂ZnSiO₄; Cr⁴⁺:Mg₂GeO₄; Cr⁴⁺:LiGaSiO₄; Cr⁴⁺:Y₂SiO₅; Cr⁴⁺:Ca₂AI₂SiO₇; Cr⁴⁺:Y₃AI₅Qι₂; Cr⁴⁺:Zn₂SiO₄; Cr⁴⁺:MgSiO₄; Cr⁴⁺:LiAIO₂; Cr⁴⁺:LiGaO₂; Cr⁴⁺:LiAIO₂; Cr⁴⁺:Lu₃AI₅O₁₂; Cr⁴⁺:Y₃AI₅O₁₂ (YAG); Cr⁴⁺:Y₃Ga₅O₁₂; Cr⁴⁺:Gd₃Ga₅O₁₂; Cr⁴⁺:Ti:AI₂O₃; Cr⁴⁺:Ca₂SiO₄; Cr⁴⁺:LiAIGeO₄; Cr⁴⁺:CaMgSiO₄; Cr⁴⁺:LiScGeO4; Cr⁴⁺:LilnGeO ; and Cr⁴⁺:LiScGeO₄.

3. The optical device of Claim 1 , wherein the optically transparent strip is made of at least one material chosen from glasses and polymers.

4. The optical device of Claim 1 , wherein the at least one strip has a refractive index ranging from about 1.5 to about 2.5.

5. The optical device of Claim 1 , wherein the at least one strip has a refractive index ranging from about 1.8 to about 2.0.

6. The optical device of Claim 3, wherein the polymers are chosen from hydrocarbon polymers, nanoporous random glassy polymers, and polymer nanocomposites.

7. The optical device of Claim 6, wherein the hydrocarbon polymers and the nanoporous random glassy polymers are chosen from halogenated elastomers, perhalogenated elastomers, halogenated plastics, and perhalogenated plastics.

8. The optical device of Claim 6, wherein the hydrocarbon polymers and the nanoporous random glassy polymers are chosen from polymers, copolymers, and terpolymer comprising at least one halogenated monomer chosen from the following formulas:

wherein:

- R¹, R², R³, R⁴, and R⁵, which may be identical or different, are each chosen from linear and branched hydrocarbon-based chains, capable of forming at least one carbon-based ring, being saturated or unsaturated, wherein at least one hydrogen atom of the hydrocarbon-based chains may be halogenated; a halogenated alkyl, a halogenated aryl, a halogenated cyclic alky, a halogenated alkenyl, a halogenated alkylene ether, a halogenated siloxane, a halogenated ether, a halogenated polyether, a halogenated thioether, a halogenated silylene, and a halogenated silazane;

- Yi and Y₂, which may be identical or different, are chosen from H, F, CI, and Br atoms; and

- Y₃ is chosen from H, F, CI, and Br atoms, CF₃, and CH₃.

9. The optical device of Claim 8, wherein R¹, R², R³, R⁴, and R⁵ are at least partially fluorinated.

10. The optical device of Claim 8, wherein R¹, R², R³, R⁴, and R⁵ are completely fluorinated.

11. The optical device of Claim 8, wherein at least one of R¹, R², R³, R⁴, and R⁵ is chosen from C₁-C₁₀, linear and branched, saturated and unsaturated hydrocarbon-based chains.

12. The optical device of Claim 6, wherein the hydrocarbon polymers and the nanoporous random glassy polymers are chosen from polymer condensation products of at least one of the following monomeric reactions:

HO-R-OH + NCO-R'-NCO; and HO-R-OH + Ary¹ -Ary²,

wherein:

- R and R\ which may be identical or different, are chosen from one of halogenated alkylenes, halogenated siloxanes, halogenated ethers, halogenated silylenes, halogenated arylenes, halogenated polyethers, and halogenated cyclic alkylenes; and - Ary¹ and Ary², which may be identical or different, are chosen from halogenated aryls and halogenated alkyl aryls.

13. The optical device of Claim 6, wherein the hydrocarbon polymers and the nanoporous random glassy polymers are chosen from halogenated polycarbonates, halogenated cyclic olefin polymers, halogenated cyclic olefin copolymers, halogenated polycyclic polymers, halogenated polyimides, halogenated polyether ether ketones, halogenated epoxy resins, and halogenated polysulfones.

14. The optical device of Claim 6, wherein the hydrocarbon polymers and the nanoporous random glassy polymers are chosen from halogenated polymers comprising at least one functional group chosen from phosphinates, phosphates, carboxylates, silanes, siloxanes, and sulfides.

15. The optical device of Claim 14, wherein the at least one functional group is chosen from POOH, POSH, PSSH, OH, SO₃H, SO₃R, SO₄R, COOH, NH₂, NHR, NR₂, CONH₂, and NH-NH₂, wherein R is chosen from linear and branched hydrocarbon-based chains, capable of forming at least one carbon- based ring, being saturated or unsaturated; alkylenes, siloxanes, silanes, ethers, polyethers, thioethers, silylenes, and silazanes.

16. The optical device of Claim 6, wherein the hydrocarbon polymers and the nanoporous random glassy polymers are chosen from homopolymers and copolymers of vinyl, acrylate, methacrylate, vinyl aromatic, vinyl ester, alpha beta unsaturated acid ester, unsaturated carboxylic acid ester, vinyl chloride, vinylidene chloride, and diene monomers.

17. The optical device of Claim 6, wherein the hydrocarbon polymers and the nanoporous random glassy polymers are chosen from poly[2,2- bistrifluoromethyl-4,5-difluoro-1 ,3-dioxole-co-tetrafluoroethylene], poly[2,2- bisperfluoroalkyl-4,5-difluoro-1 ,3-dioxole-co-tetrafluoroethylene], poly[2,3- (perfluoroalkenyl) perfluorotetrahydrofuran], poly[2,2,4-trifluoro-5- trifluoromethoxy-1 ,3-dioxole-co-tetrafluoroethylene], poly(pentafluorostyrene), fluorinated polyimide, fluorinated polymethylmethacrylate, polyfluoroacrylates, polyfluorostyrene, fluorinated polycarbonates, fluorinated poly (N-vinylcarbazole), fluorinated acrylonitrile-styrene copolymer, fluorinated Nation®, fluorinated poly(phenylenevinylene), perfluoro-polycyclic polymers, polymers of fluorinated cyclic olefins, and copolymers of fluorinated cyclic olefins.

18. The optical device of Claim 6, wherein the hydrocarbon polymers and the nanoporous random glassy polymers are chosen from polymethylmethacrylates, polystyrenes, polycarbonates, polyimides, epoxy resins, cyclic olefin copolymers, cyclic olefin polymers, acrylate polymers, PET, polyphenylene vinylene, polyether ether ketone, poly (N-vinylcarbazole), acrylonitrile-styrene copolymer, and poly(phenylenevinylene).

19. The optical device of Claim 6, wherein the polymer nanocomposites comprise a host matrix comprising at least one polymer chosen from the hydrocarbon polymers and the nanoporous random glassy polymers; and a plurality of nanoparticles within the host matrix.

20. The optical device of Claim 19, wherein the nanoparticles are chosen from nanoparticles made of at least one of metal, glass, ceramics, refractory materials, natural and synthetic polymers, and dyes.

21. The optical device of Claim 19, wherein the nanoparticles are chosen from nanoparticles made of at least one of dielectric materials, carbon and graphites, ions, alloys, compounds, composites, and complex of transition metal elements, rare-earth metal elements, group VA elements, semiconductors, alkaline earth metal elements, alkali metal elements, group IIIA elements, and group IVA elements.

22. The optical device of Claim 19, wherein the nanoparticles comprise at least one coating.

23. The optical device of Claim 19, wherein the nanoparticles comprise at least one semiconductor material.

24. The optical device of Claim 23, wherein the at least one semiconductor material is chosen from Si, PbS, Ge, GaP, GaAs, InP, InAs, InSb, PbSe, and PbTe.

25. The optical device of Claim 21 , wherein the dielectric materials are chosen from NaCI, TiO₂, SiO₂, B₂O₃, Ge₂O₃, ZnO₂, LiNbO₃, and BaTiO₃.

26. The optical device of Claim 19, wherein the nanoparticles comprise at least one of oxide, phosphate, halophosphate, phosphinate, arsenate, sulfate, borate, aluminate, gallate, silicate, germanate, vanadate, niobate, tantalite, tungstate, molybdate, alkalihalogenate, halogenide, nitride, selenide, sulfide, sulfoselenide, tetrafluoroborate, hexafluorophosphate, phosphonate, and oxysulfide.

27. The optical device of Claim 1 , further comprising a layer between the Cr⁴⁺ doped crystal substrate and the at least one strip, wherein the layer has a refractive index higher than the Cr⁴⁺ doped crystal.

28. The optical device of Claim 27, wherein the layer is a part of the Cr ⁺ doped crystal substrate that has been impregnated or ion-exchanged with at least one cation.

29. The optical device of Claim 1 , further comprising a polymer overcladding on top of the strip and Cr⁴⁺ doped crystal substrate.

30. The optical device of Claim 1 , wherein the optical device is a waveguide.

31. The optical device according to Claim 30, wherein the waveguide operates in the 1200-1600 nm wavelength window.

32. The optical device of Claim 31 , wherein the waveguide operates at approximately the 1310 nm wavelength.

33. The optical device of Claim 1 , wherein the optical device is an optical waveguide amplifier.

34. The optical device of Claim 33, wherein the optical waveguide amplifier operates in the 1200-1600 nm wavelength window.

35. The optical device of Claim 32, wherein the optical waveguide amplifier operates at approximately 1310 nm.

36. A strip-loaded optical waveguide amplifier, comprising a Cr⁴⁺ doped crystal substrate and at least one strip disposed on said substrate, wherein said at least one strip has a higher refractive index than that of said substrate.

37. The strip-loaded optical waveguide amplifier of Claim 36, which operates in the 1200-1600 nm wavelength window.

38. The strip-loaded optical waveguide amplifier of Claim 37, which operates at approximately 1310 nm.

39. The strip-loaded optical waveguide amplifier of Claim 36, further comprising a layer between the Cr⁴⁺ doped crystal substrate and the at least one strip, wherein the layer has a refractive index higher than the Cr⁴⁺ doped crystal.

40. The strip-loaded optical waveguide amplifier of Claim 39, wherein the layer is a part of the Cr⁴⁺ doped crystal substrate that has been impregnated or ion-exchanged with at least one cation.

41. The optical device of Claim 1 , wherein the Cr⁴⁺ doped crystal is co- doped with another ion.

42 The optical device of Claim 41 , wherein said ion is Yb³⁺.