Claims:Claims
What is claimed is:
1. An optical fiber (100) comprising:

a core region defined by a region around a central longitudinal axis, the core region having:
a first region (102) defined from the central longitudinal axis to a first radius r1 from the central longitudinal axis of the optical fiber(100), wherein the first region (102) has a first refractive index a1;
a second region (104) defined from the first radius r1 to a second radius r2 from the central longitudinal axis of the optical fiber (100), wherein the second region (104) has a second refractive index a2;
a third region (106) defined from the second radius r2 to a third radius r3 from the central longitudinal axis of the optical fiber (100), wherein the third region (106) has a third refractive index a3; and
a fourth region (108) defined from the third radius r3 to a fourth radius r4 from the central longitudinal axis of the optical fiber (100), wherein the fourth region (108) has a fourth refractive index a4, wherein the first region (102), the second region (104), the third region (106) and the fourth region (108) are concentrically arranged, wherein the first refractive index a1 is less than the second refractive index a2, the third refractive index a3 is more than the second refractive index a2 and the fourth refractive index a4 is less than the third refractive index a3; and

a cladding having a fifth refractive index a5 and a fifth radius r5 from the central longitudinal axis of the optical fiber, the cladding is defined by a fifth region (110) concentrically surrounding the fourth region (108), wherein the fifth refractive index a5 and the fifth radius r5 are fixed.

2. The optical fiber (100) as recited in claim 1, wherein the first region (102), the second region (104) and the third region (106) form an increasing step profile.

3. The optical fiber (100) as recited in claim 1, wherein the refractive index a1 of the first region (102) is in a range of 1.445 to 1.46 at 1550 nm and the radius r1 of the first region (102) is in a range of 0.1 μm to 0.3 μm.

4. The optical fiber (100) as recited in claim 1, wherein the refractive index a2 of the second region (104) is in a range of 1.447 to 1.46 at 1550 nm and the radius r2 of the second region (104) is in a range of 0.35 μm to 0.67 μm.

5. The optical fiber (100) as recited in claim 1, wherein the refractive index a3 of the third region (106) is in a range of 1.448 to 1.46 at 1550 nm and the radius r3 of the third region (106) is in a range of 1.325 μm to 1.85 μm.

6. The optical fiber (100) as recited in claim 1, wherein the refractive index a4 of the fourth region (108) is in a range of 1.45 to 1.46 at 1550 nm and the radius r4 of the fourth region (108) is in a range of 2.63 μm to 3.14 μm.

7. The optical fiber (100) as recited in claim 1, wherein the fifth refractive index a5 of the fifth region (110) is 1.444 at 1550 nm and the fifth radius r5 of the fifth region (110) is 62.5 μm.

8. The optical fiber (100) as recited in claim 1, wherein the optical fiber has a dispersion in a range of 1 to 4.6 ps/km.nm at 1460 nm and 3.6 to 9.28 ps/km.nm at 1550 nm.

9. The optical fiber (100) as recited in claim 1, wherein the optical fiber has a maximum macro bending loss of 0.03 dB/100 turns at a wavelength of 1550 nm for 32 mm bending diameter.

10. The optical fiber (100) as recited in claim 1, wherein a cable cut off wavelength of the optical fiber is less than equal to 1260 nm.

11. The optical fiber (100) as recited in claim 1, wherein a power budget of the optical fiber when compared to an optical fiber with a macro bending loss of 0.3 dB/100 turns at a wavelength of 1550 nm at a 32 mm bending diameter is reduced by at least 2.7 dB for a fiber optic link of 1000 km with 20 connections and having 50 turns at a 32 mm bending diameter at a point of connection.
Dated: 30th Day of March, 2016 Signature
Arun Kishore Narasani Patent Agent

, Description:TECHNICAL FIELD
[0001] The present disclosure relates to the field of optical fiber transmission. More particularly, the present disclosure relates to a long haul low macro bend loss optical fiber suitable for Dense Wavelength Division Multiplex (DWDM) applications.

BACKGROUND
[0002] Over the last few years, optical fibers are being widely used for communications. One such type of optical fibers is non-zero dispersion shifted optical fibers used in wavelength division multiplexing systems for long haul applications. Typically, the performance of these optical fibers is determined based on a reduction in dispersion and bending losses over a broad range of bandwidth. In general, the dispersion and bending losses are minimized based on a refractive index profile. The refractive index profile defines the properties of a core section and a cladding section. Also, the refractive index profile illustrates a relationship between the refractive index of the optical fiber with a radius of the optical fiber. Further, this profile is determined based on a concentration of dopants and materials used during manufacturing. Furthermore, the dispersion and bending losses are controlled by varying the refractive index profile.

[0003] Currently deployed non-zero dispersion shifted optical fibers have certain drawbacks. The non-zero dispersion shifted fibers of G.656 category exhibit high macro bending losses leading to increase in system penalty and network budget. This leads to reduction in reliability of optical fiber under bending conditions.

[0004] In light of the above stated discussion, there is a need for an optical fiber that has low macro bending losses while being suitable for DWDM systems in long haul communications.

OBJECT OF THE DISCLOSURE
[0005] A primary object of the present disclosure is to provide an optical fiber, which exhibits low macro bending losses and low dispersion values.

[0006] Another object of the present disclosure is to provide the optical fiber that is suitable for DWDM communications.

[0007] Yet another object of the present disclosure is to provide the optical fiber that reduces power budget of optical the fiber system.

SUMMARY
[0008] In an aspect of the present disclosure, the present disclosure provides an optical fiber. The optical fiber includes a core region. The core region is defined by a region around the central longitudinal axis of the optical fiber. In addition, the core region has a first region. The first region is defined from the central longitudinal axis of the optical fiber to a first radius r1 from the central longitudinal axis of the optical fiber. Moreover, the core region has a second region. The second region is defined from the first radius r1 to a second radius r2 from the central longitudinal axis of the optical fiber. Further, the core region has a third region. The third region is defined from the second radius r2 to a third radius r3 from the central longitudinal axis of the optical fiber. Furthermore, the core region includes a fourth region. The fourth region is defined from the third radius r3 to a fourth radius r4 from the central longitudinal axis of the optical fiber. Also, the optical fiber includes a cladding. The cladding has a fifth refractive index a5 and a fifth radius r5 from the central longitudinal axis of the optical fiber. Moreover, the cladding is defined by a fifth region. The fifth region concentrically surrounds the fourth region. In addition, the first region has a first refractive index a1. Moreover, the second region has a second refractive index a2. Further, the third region has a third refractive index a3. Furthermore, the fourth region has a fourth refractive index a4. Also, the first region, the second region, the third region and the fourth region are concentrically arranged. In addition, the first refractive index a1 is less than the second refractive index a2 and the third refractive index a3 is more than the second refractive index a2. Also, the fourth refractive index a4 is less than the third refractive index a3. In addition, the fifth refractive index a5 and the fifth radius r5 are fixed.

[0009] In an embodiment of the present disclosure, the first region, the second region and the third region of the core form an increasing step profile.

[0010] In an embodiment of the present disclosure, the refractive index a1 of the first region is in a range of 1.445 to 1.46 at 1550 nm and the radius r1 of the first region is in a range of 0.1 μm to 0.3 μm.

[0011] In an embodiment of the present disclosure, the refractive index a2 of the second region is in a range of 1.447 to 1.46 at 1550 nm and the radius r2 of the second region is in a range of 0.35 μm to 0.67 μm.

[0012] In an embodiment of the present disclosure, the refractive index a3 of the third region is in a range of 1.448 to 1.46 at 1550 nm and the radius r3 of the third region is in a range of 1.325 μm to 1.85 μm.

[0013] In an embodiment of the present disclosure, the refractive index a4 of the fourth region is in a range of 1.45 to 1.46 at 1550 nm and the radius r4 of the fourth region is in a range of 2.63 μm to 3.14 μm.

[0014] In an embodiment of the present disclosure, the refractive index a5 of the fifth region is 1.444 at 1550 nm and the radius r5 of the fifth region is 62.5 μm.

[0015] In an embodiment of the present disclosure, the optical fiber has the dispersion of 8.9 ps/nm.km at a wavelength of 1550 nm.

[0016] In an embodiment of the present disclosure, the optical fiber has the macro bending loss of 0.03 dB/100 turns at a wavelength of 1550 nm for 32 mm bending diameter.

[0017] In an embodiment of the present disclosure, the optical fiber has a pre-defined range of a cable cut off wavelength. In addition, a maximum cable cut off wavelength of the optical fiber is 1260 nm.

[0018] In an embodiment of the present disclosure, a power budget of the optical fiber when compared to an optical fiber with a macro bending loss of 0.3 dB/100 turns at a wavelength of 1550 nm at a 32 mm bending diameter is reduced by at least 2.7 dB for a fiber optic link of 1000 km with 20 connections and having 50 turns at a 32 mm bending diameter at a point of connection.
STATEMENT OF THE DISCLOSURE
[0019] The present disclosure relates to an optical fiber. The optical fiber includes a core region. The core region is defined by a region around a central longitudinal axis of the optical fiber. In addition, the core region has a first region. The first region is defined from the central longitudinal axis to a first radius r1 from the central longitudinal axis of the optical fiber. Moreover, the core region has a second region. The second region is defined from the first radius r1 to a second radius r2 from the central longitudinal axis of the optical fiber. Further, the core region has a third region. The third region is defined from the second radius r2 to a third radius r3 from the central longitudinal axis of the optical fiber. Furthermore, the core region includes a fourth region. The fourth region is defined from the third radius r3 to a fourth radius r4 from the central longitudinal axis of the optical fiber. Also, the optical fiber includes a cladding. The cladding has a fifth refractive index a5 and a fifth radius r5 from the central longitudinal axis of the optical fiber. Moreover, the cladding is defined by a fifth region. The fifth region concentrically surrounds the fourth region. In addition, the first region has a first refractive index a1. Moreover, the second region has a second refractive index a2. Further, the third region has a third refractive index a3. Furthermore, the fourth region has a fourth refractive index a4. Also, the first region, the second region, the third region and the fourth region are concentrically arranged. In addition, the first refractive index a1 is less than the second refractive index a2 and the third refractive index a3 is more than the second refractive index a2. Also, the fourth refractive index a4 is less than the third refractive index a3. In addition, the fifth refractive index a5 and the fifth radius r5 are fixed.

BRIEF DESCRIPTION OF FIGURES
[0020] Having thus described the disclosure in general terms, reference will now be made to the accompanying figures, wherein:

[0021] FIG. 1 illustrates a cross-sectional view of an optical fiber, in accordance with various embodiments of the present disclosure; and

[0022] FIG. 2 illustrates a refractive index profile of the optical fiber, in accordance with various embodiments of the present disclosure.

[0023] It should be noted that the accompanying figures are intended to present illustrations of exemplary embodiments of the present disclosure. These figures are not intended to limit the scope of the present disclosure. It should also be noted that accompanying figures are not necessarily drawn to scale.

DETAILED DESCRIPTION
[0024] In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present technology. It will be apparent, however, to one skilled in the art that the present technology can be practiced without these specific details. In other instances, structures and devices are shown in block diagram form only in order to avoid obscuring the present technology.

[0025] Reference in this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present technology. The appearance of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but not other embodiments.

[0026] Moreover, although the following description contains many specifics for the purposes of illustration, anyone skilled in the art will appreciate that many variations and/or alterations to said details are within the scope of the present technology. Similarly, although many of the features of the present technology are described in terms of each other, or in conjunction with each other, one skilled in the art will appreciate that many of these features can be provided independently of other features. Accordingly, this description of the present technology is set forth without any loss of generality to, and without imposing limitations upon, the present technology.

[0027] FIG. 1 illustrates a cross-sectional view of an optical fiber 100, in accordance with various embodiments of the present disclosure. The optical fiber 100 is a fiber used for transmitting information as light pulses from one end to another. In addition, the optical fiber 100 is a thin strand of glass or plastic capable of transmitting optical signals. The optical fiber 100 is configured to transmit large amounts of information over long distances with relatively low attenuation. In an embodiment of the present disclosure, the optical fiber 100 is utilized for broadband communication applications.

[0028] In another embodiment of the present disclosure, the optical fiber 100 may be utilized for other applications. The optical fiber 100 is a non-zero dispersion shifted fiber. The non-zero dispersion shifted fiber is a single mode optical fiber used for long haul transmission systems. The single mode optical fiber is a fiber which is configured for transmission of single mode of light. In addition, the non-zero dispersion shifted fiber is a fiber used for reducing dispersion and macro bending losses in broadband communications. The dispersion corresponds to a spreading of the optical signals over time.

[0029] In an embodiment of the present disclosure, the type of the dispersion which occurs inside the single mode optical fiber is chromatic dispersion. The chromatic dispersion is the spreading of the optical signals which results from different speeds of light rays travelling inside the optical fiber 100. Moreover, the chromatic dispersion occurs due to material dispersion and waveguide dispersion.

[0030] The material dispersion occurs due to a change in a refractive index of the optical fiber 100 with an optical frequency. Moreover, the waveguide dispersion occurs due to dependency of mode propagation on wavelength. Going further, the non-zero dispersion shifted fiber is a fiber which exhibits the chromatic dispersion at a wavelength of 1550 nanometer. In addition, the chromatic dispersion exhibited is less than the chromatic dispersion of a standard single mode optical fiber at a wavelength of 1550 nanometers. In an embodiment of the present disclosure, the optical fiber 100 has a pre-determined value of dispersion (provided below in the detailed description of FIG. 2).

[0031] In an embodiment of the present disclosure, the non-zero dispersion shifted fiber enables decrease of the dispersion over a range of wavelength and decreases non-linearity in the optical fiber 100. The range of wavelength corresponds to a range in which the optical fiber 100 is configured to operate. In an embodiment of the present disclosure, the optical fiber 100 is used for wavelength division multiplexing systems. The wavelength division multiplexing system is a system in which the optical signals with different wavelengths are combined and transmitted together. Accordingly, the optical signals are separated at another end.

[0032] Further, the wavelength division multiplexing systems is of two types. The two types of the wavelength division multiplexing systems include coarse wavelength division multiplexing system and dense wavelength division multiplexing system. The coarse wavelength division multiplexing system utilizes a small number of channels with a nominal wavelength in a range of 1310 nanometer and 1625 nanometer. The dense wavelength division multiplexing system utilizes a large number of channels.

[0033] In an embodiment of the present disclosure, the non-zero dispersion shifted fiber is a positive non-zero dispersion shifted fiber. The positive non-zero dispersion shifted fiber exhibits a positive chromatic dispersion at the operational wavelength. In an embodiment of the present disclosure, the optical fiber 100 complies with specific telecommunication standards. The telecommunication standards are defined by International Telecommunication Union-Telecommunication (hereinafter “ITU-T”). In an embodiment of the present disclosure, the optical fiber 100 is compliant with G.656 recommendation standard set by the ITU-T.

[0034] Furthermore, the ITU-T G.656 recommendation describes a geometrical, mechanical and transmission attributes of the single mode optical fiber (the optical fiber 100). In an embodiment of the present disclosure, the range of wavelength for the optical fiber 100 as per the ITU-T G.656 standard is 1460 nanometer to 1625 nanometer. Moreover, the ITU-T G.656 standard defines a plurality of attributes associated with the optical fiber 100. The plurality of attributes includes a mode field diameter, a cladding diameter, cable cut-off wavelength, macro bending loss, dispersion and refractive index. In addition, the plurality of attributes includes core concentricity error, cladding non-circularity, attenuation coefficient and the like.

[0035] The mode field diameter defines a section or area of the optical fiber 100 in which the optical signals travel. Moreover, the mode field diameter is larger than a core diameter at 1550 nm. The cable cut-off wavelength is a wavelength above which the single mode operation of the optical fiber 100 is enabled. In addition, the refractive index of the optical fiber is a property which determines the velocity with which the optical signal travels inside the optical fiber 100. In an embodiment of the present disclosure, each of the plurality of attributes has a specific value or a range of value (mentioned below in the detailed description of the FIG. 2).

[0036] As shown in the FIG. 1, the optical fiber 100 includes a core region and a cladding region. The core region is an inner part of the optical fiber 100 and the cladding section is an outer part of the optical fiber 100. Moreover, the core region is defined by a region around a central longitudinal axis of the optical fiber 100. In addition, the cladding region surrounds the core region. The core region and the cladding region are formed along the central longitudinal axis of the optical fiber 100. Moreover, the core region and the cladding region are formed during the manufacturing stage of the optical fiber 100. The core region has a refractive index which is greater than a refractive index of the cladding region. In an embodiment of the present disclosure, the core region has a higher refractive index than the cladding region. In an embodiment of the present disclosure, the refractive index profile changes from a center of the optical fiber 100 to the radius of the optical fiber 100.

[0037] The refractive index profile determines a relationship between the refractive index of the optical fiber 100 with a radius of the optical fiber 100. In addition, the refractive index profile illustrates a change in the refractive index of the optical fiber 100 with an increase in the radius of the optical fiber 100. Also, the refractive index profile is maintained as per a desired level based on a concentration of chemicals used for the production of the optical fiber 100. In an embodiment of the present disclosure, the production of the optical fiber 100 is carried out after construction of an optical fiber preform.

[0038] Moreover, the refractive index profile of the optical fiber 100 is determined during the manufacturing of the optical fiber preform. The refractive index profile is determined based on a concentration of chemicals used during the manufacturing of the optical fiber preform. The chemicals used for the manufacturing of the optical fiber 100 include one or more materials and one or more dopants. Moreover, the one or more materials and the one or more dopants are deposited over a surface of an initial material by performing flame hydrolysis. In an embodiment of the present disclosure, the initial material is a substrate rod or a tube. The deposition is done for achieving a pre-structure of the optical fiber 100.

[0039] Further, the one or more materials correspond to a mixture of chemicals used for forming the optical fiber 100. The one or more materials include silicon dioxide. The silicon dioxide is deposited over the initial material during the manufacturing of the optical fiber 100. Also, silicon dioxide is formed by using a precursor material. The precursor material corresponds to silicon tetrachloride. In an embodiment of the present disclosure, the one or more dopants include germanium dioxide, phosphorous pentoxide, aluminium trioxide and the like. Moreover, germanium dioxide is formed by using a precursor material. The precursor material corresponds to germanium tetrachloride. In addition, each of the one or more dopants in added in a pre-determined quantity based on a specific requirement. Moreover, the one or more dopants are added for defining the refractive index profile of the core region of the optical fiber 100.

[0040] Further, the optical fiber 100 is manufactured by performing a specific chemical deposition technique of a plurality of chemical deposition techniques. Each of the plurality of chemical deposition techniques performs a chemical vapor deposition over a surface of the initial material by flame hydrolysis or inside the initial material. The plurality of chemical deposition techniques includes a modified chemical vapor deposition technique, an outside vapor deposition technique, an axial vapor deposition technique and the like. Each of the plurality of chemical deposition techniques ensures a specific refractive index required. Also, each of the plurality of chemical deposition techniques is used to manufacture the core region and the cladding region of the optical fiber 100.

[0041] In an embodiment of the present disclosure, the radius of the optical fiber 100 is maintained under a pre-defined value set as per the ITU-T standards. In addition, the optical signals to be transmitted travel through the core region of the optical fiber 100. The optical signals are confined inside the core region based on a property of total internal reflection. In an embodiment of the present disclosure, the core region is associated with a different refractive index profile.

[0042] In an embodiment of the present disclosure, the cladding region is defined by a different refractive index profile. Moreover, the refractive index profile of the core region and the cladding region is shown through a single graph (as shown in the FIG. 2). Going further, the optical fiber 100 includes the core region. The core region has the refractive index profile (as shown in the FIG. 2). In addition, the optical fiber 100 includes a plurality of regions in the core region of the optical fiber 100. In an embodiment of the present disclosure, the core region of the optical fiber 100 is divided into the plurality of regions.

[0043] Each of the plurality of regions is defined by a corresponding refractive index and a corresponding radius. In an embodiment of the present disclosure, the refractive index of each of the plurality of regions of the core region is different. In an embodiment of the present disclosure, the radius of each of the plurality of regions of the core region is different. In an embodiment of the present disclosure, the refractive index of each of the plurality of regions of the core region changes in steps. In an embodiment of the present disclosure, the refractive index profile of the core region forms a step profile (as shown in the FIG. 2).

[0044] Further, in an embodiment of the present disclosure, the refractive index profile of the core region of the optical fiber 100 changes from the center of the optical fiber 100 to the radius of the core. Moreover, the refractive index of each of the plurality of regions of the core region has a pre-defined range of value. In addition, the radius of each of the plurality of regions of the core region has a pre-defined range of value. In an embodiment of the present disclosure, the pre-defined range of value of the refractive index is set to enable minimum dispersion and low macro bending loss.

[0045] In an embodiment of the present disclosure, the pre-defined range of value of the refractive index of each of the plurality of regions is set to maintain the dispersion and macro bending loss in a pre-defined range or value. The pre-defined range or value is decided based on the ITU-T G.656 standard. In an embodiment of the present disclosure, the pre-defined range of the value of the core radius is optimized to enable the minimum dispersion and low macro bending loss. In addition, each region of the plurality of regions has the corresponding refractive index value.

[0046] Further, in an embodiment of the present disclosure, the refractive index of each region of the plurality of regions is fixed over a cross-sectional area of each region. Going further, the core region has a first region 102, a second region 104, a third region 106 and a fourth region 108. In an embodiment of the present disclosure, the plurality of regions includes the first region 102, the second region 104, the third region 106 and the fourth region 108. Moreover, the first region 102, the second region 104, the third region 106 and the fourth region 108 are concentrically arranged.

[0047] Furthermore, the second region 104 surrounds the first region 102, the third region 106 surrounds the second region 104 and the fourth region 108 surrounds the third region 106. The first region 102, the second region 104, the third region 106 and the fourth region 108 is associated with the corresponding refractive index and the corresponding radius. The refractive index of the second region 104 is more than the refractive index of the first region 102. In addition, the refractive index of the third region 106 is more than the refractive index of the second region 104. Moreover, the refractive index of the fourth region 108 is less than the refractive index of the third region 106.

[0048] In an embodiment of the present disclosure, the refractive index of the first region 102, the second region 104, the third region 106 and the fourth region 108 changes in steps. In an embodiment of the present disclosure, the first region 102, the second region 104 and the third region 106 form an increasing step profile. In an embodiment of the present disclosure, the third region 106 and the fourth region 108 form a decreasing step profile. In addition, the refractive index of the first region 102, the second region 104, the third region 106 and the fourth region 108 is optimized for low macro bending loss and low dispersion. Moreover, the macro bending loss and the dispersion is optimized within a pre-defined limit specified by the ITU-T. In an embodiment of the present disclosure, the refractive index and the radius are optimized based on a change in the concentration of a dopant used. In an embodiment of the present disclosure, the dopant includes germanium dioxide, phosphorous pentoxide, aluminium trioxide and the like.

[0049] Further, the radius of the first region 102, the second region 104, the third region 106 and the fourth region 108 is optimized for the low macro bending loss and low dispersion. Moreover, the macro bending loss and the dispersion is optimized within a pre-defined limit specified by the ITU-T. The radius of the second region 104 is more than the radius of the first region 102. In addition, the radius of the third region 106 is more than the radius of the second region 104 and the first region 102. Also, the radius of the fourth region 108 is more than the radius of the third region 106, the second region 104 and the first region 102.

[0050] In an embodiment of the present disclosure, the radius of the first region 102, the second region 104, the third region 106 and the fourth region 108 increases from the center of the core region. Going further, the first region 102 is defined from the central longitudinal axis of the optical fiber 100 to a first radius r1 from the central longitudinal axis of the optical fiber 100. The first region 102 has a first refractive index a1 (provided below in the detailed description of the FIG. 2). In addition, the second region 104 is defined from the first radius r1 to a second radius r2 from the central longitudinal axis of the optical fiber 100. The second region 104 has a second refractive index a2 (mentioned below in the detailed description of the FIG. 2). Further, the third region 106 is defined from the second radius r2 to a third radius r3 from the central longitudinal axis of the optical fiber 100. The third region 106 has a third refractive index a3 (stated below in the detailed description of the FIG. 2). Furthermore, the fourth region 108 defined from the third radius r3 to a fourth radius r4 from the central longitudinal axis of the optical fiber 100. The fourth region 108 has a fourth refractive index a4 (provided below in the detailed description of the FIG. 2).

[0051] In an embodiment of the present disclosure, the first refractive index a1 is less than the second refractive index a2 and the third refractive index a3 is more than the second refractive index a2. Also, the fourth refractive index a4 is less than the third refractive index a3. In addition, the refractive index and the radius associated with each region of the core are optimized for achieving a pre-defined value of the dispersion and the macro bending loss.

[0052] Further, the optical fiber 100 includes a cladding. The cladding surrounds the core region. In addition, the cladding is concentrically arranged around the core region. Moreover, the cladding covers the core region. Further, the cladding is defined by a specific refractive index and a specific radius. In an embodiment of the present disclosure, the refractive index and the radius of the cladding is optimized for achieving the pre-defined value of the dispersion and the macro bending loss in the optical fiber 100 (provided in the detailed description of the FIG. 2).

[0053] In an embodiment of the present disclosure, the radius of the cladding is more than the radius of the core region. In an embodiment of the present disclosure, the refractive index of the cladding is constant throughout the cross-sectional area. In an embodiment of the present disclosure, the radius of the cladding is fixed (mentioned below in the detailed description of the FIG. 2).

[0054] As shown in the FIG. 1, the cladding is defined by a fifth region 110. The fifth region 110 concentrically surrounds the fourth region 108. In addition, the fifth region 110 has a fifth refractive index a5 and a fifth radius r5 from the central longitudinal axis of the optical fiber 100. In an embodiment of the present disclosure, the fifth refractive index a5 is less than the first refractive index a1, the second refractive index a2, the third refractive index a3 and the fourth refractive index a4. In an embodiment of the present disclosure, the fifth radius r5 is more than the first radius r1, the second radius r2, the third radius r3 and the fourth radius r4.

[0055] In an embodiment of the present disclosure, the value of the fifth refractive index a5 is constant throughout a cross-sectional area of the fifth region 110 (as shown in the FIG. 2). In an embodiment of the present disclosure, the fifth radius r5 of the fifth region 110 is fixed (mentioned below in the detailed description of the FIG. 2). Further, the value of the fifth refractive index a5 and the fifth radius r5 is optimized for achieving the pre-defined value of the dispersion and the macro bending loss.

[0056] FIG. 2 illustrates a refractive index profile 200 of the optical fiber 100, in accordance with various embodiments of the present disclosure. It may be noted that to explain a graphical appearance of the refractive index profile 200, references will be made to the structural elements of the optical fiber 100. The refractive index profile 200 illustrates a relationship between the refractive index of the optical fiber 100 and the radius of the optical fiber 100 (as stated above in the detailed description of the FIG. 1). In an embodiment of the present disclosure, the refractive index profile 200 shows the change in the refractive index of the optical fiber 100 with the radius of the optical fiber 100.

[0057] Further, in an embodiment of the present disclosure, the refractive index profile 200 is a step profile. In an embodiment of the present disclosure, the first region 102, the second region 104 and the third region 106 form the increasing step profile. In an embodiment of the present disclosure, the third region 106 and the fourth region 108 form the decreasing step profile. Further, the refractive index a1 of the first region 102 is in a range of 1.445 to 1.46 at 1550 nm. In an embodiment of the present disclosure, the refractive index a1 of the first region 102 is 1.45 at 1550 nm. In addition, the radius r1 of the first region 102 is in a range of 0.1 μm to 0.3 μm. In an embodiment of the present disclosure, the radius r1 of the first region 102 is 0.25 μm.

[0058] Furthermore, the refractive index a2 of the second region 104 is in a range of 1.447 to 1.46. In an embodiment of the present disclosure, the refractive index a2 of the second region 104 is 1.4515 at 1550 nm. In addition, the radius r2 of the second region 104 is in a range of 0.35 μm to 0.67 μm. In an embodiment of the present disclosure, the radius r2 of the second region 104 is 0.65 μm. Moreover, the refractive index a3 of the third region 106 is in a range of 1.448 to 1.46 at 1550 nm. In an embodiment of the present disclosure, the refractive index a3 of the third region 106 is 1.453 at 1550 nm. In addition, the radius r3 of the third region 106 is in a range of 1.325 μm to 1.85 μm. In an embodiment of the present disclosure, the radius r3 of the third region 106 is 1.83 μm.

[0059] Going further, the refractive index a4 of the fourth region 108 is in a range of 1.45 to 1.46 at 1550 nm. In an embodiment of the present disclosure, the refractive index a4 of the fourth region 108 is 1.45 at 1550 nm. In addition, the radius r4 of the fourth region 108 is in a range of 2.63 μm to 3.14 μm. In an embodiment of the present disclosure, the radius r4 of the fourth region 108 is 3.13 μm. Moreover, the fifth refractive index a5 of the fifth region 110 is 1.444 at 1550 nm. Also, the fifth radius r5 of the fifth region 110 is 62.5 μm.

[0060] Further, the optical fiber 100 has the dispersion in a range of 1 to 4.6 ps/nm.km at a wavelength of 1460 nm and 3.6 to 9.28 ps/nm.km at a wavelength of 1550 nm. In addition, the optical fiber 100 has the maximum macro bending loss of 0.03 dB/100 turns at a wavelength of 1550 nm for 32mm bending diameter. Furthermore, the optical fiber 100 has a pre-defined range of the cable cut off wavelength. Moreover, the cable cut off wavelength of the optical fiber 100 is less than equal to 1260 nm. In an embodiment of the present disclosure, the cable cut off wavelength of the optical fiber 100 is 1150 nm. In an embodiment of the present disclosure, the refractive index and the radius of the optical fiber 100 are optimized for achieving the pre-defined value of the dispersion and the macro bending loss.

[0061] In an embodiment of the present disclosure, a power budget of the optical fiber 100 is reduced by at least 2.7 dB for 20 connections. In an example, consider a first optical fiber with a macro bending loss of 0.03 dB/100 turns at 1550 nm for 32mm bending diameter and a second optical fiber with a macro bending loss of 0.3 dB/100 turns at 1550 nm at 32mm bending diameter. Further, a fiber optic link of 1000 km with 20 connections is taken. The fiber optic link has 50 turns at 32mm bending diameter at point of connection. Accordingly, a power requirement of the first optical fiber is 2.7 dB less as compared to the power requirement of the second optical fiber.

[0062] Going further, the present disclosure provides numerous advantages over the prior art. The present disclosure provides the non-zero dispersion shifted optical fiber with the low dispersion. In addition, the present disclosure, the non-zero dispersion shifted optical fiber provides low macro bending losses. Moreover, the present disclosure provides the low dispersion and the low macro bending loss in the single profile. In addition, the present disclosure provides the optical fiber that reduces power budget of the optical fiber system.

[0063] The foregoing descriptions of specific embodiments of the present technology have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present technology to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present technology and its practical application, to thereby enable others skilled in the art to best utilize the present technology and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present technology.

[0064] While several possible embodiments of the disclosure have been described above and illustrated in some cases, it should be interpreted and understood as to have been presented only by way of illustration and example, but not by limitation. Thus, the breadth and scope of a preferred embodiment should not be limited by any of the above-described exemplary embodiments.