Patent Description:
This section is intended to provide a background or context for the embodiments of the invention set forth in the claims. The description herein is not admitted to be prior art through included in this section.

Single-mode optical fibers and multi-mode optical fibers are significant different in mode and number, and are two different kinds of optical fibers used in different applications. The multi-mode optical fibers and single-mode optical fibers are both used in data centers. Compared with the multi-mode optical fibers, the single-mode fiber is cheaper, but single-mode transceivers are more expensive than multi-mode transceivers. By comprehensive evaluation, when the transmission distance is less than <NUM>-<NUM> meters, multi-mode transmission is still the most cost effective option.

However, as the mass and scale of the data centers increase, the system bandwidth becomes higher and the reach distance becomes longer, the transmissions of longer distances in the data centers still rely on the single-mode optical fibers. Therefore, both the single-mode optical fibers and the multi-mode optical fibers exist in a data center, which requires special processing for couplings. An optical fiber that can achieve both single and multiple transmission modes would greatly simplify cable management and reduce upgrade costs of transceivers in future. <CIT> discloses such an optical fiber that can achieve both single mode and multimode transmission.

In view of the above, it is necessary to provide an improved novel optical fiber that combines both single-mode and multi-mode transmissions.

The technical solution provided by the present invention is a novel optical fiber according to claim <NUM>. The novel optical fiber of the invention can achieve both single-mode transmission and multi-mode transmission, which greatly simplifies the management of the optical cables, reduces the future upgrade cost of transceivers. The optical fiber has a good low loss characteristics by including the transition layers. The optical fiber has a better resistance to bending by including a lower doped layer or a recessed layer.

The present invention will be further described in detail below in conjunction with the drawings and the specific embodiments.

The embodiments of the present invention will be further described in conjunction with the accompanying drawings.

The above described objects, features and advantages of the embodiments of the present invention will be described in detail in conjunction with the accompanying drawings. It should be noted that the features in the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in the description of the embodiments of the invention. The described embodiments do not represent the complete invention but only part of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention, without creative efforts, fall within the scope of the present invention.

Without specific definition, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art of the invention. The terms used in the description of the present invention are for the purpose of describing the particular embodiments, and are not intended to limit the embodiments of the invention.

The invention provides a novel optical fiber including both a single-mode fiber and a multi-mode fiber, and capable of achieving both single-mode transmission and multi-mode transmission, which greatly simplifies cable management and reduces future upgrade costs of transceivers. The novel optical fiber includes, from the inside to the outside, a single-mode core, a multi-mode layer, and an outer cover layer all coaxially disposed. The single-mode core is located at a center of the optical fiber and has an upper step index. The multi-mode layer surrounds the single-mode core, and has a refractive index of α-profile distribution. A plurality of transition layers is disposed on an inner side and optionally an outer side of the multi-mode layer. The transition layers are coaxial with the single-mode core and the outer cover layer, and the transition layers cling to the multi-mode layer. A refractive index of the transition layers disposed on the inner side of the multi-mode layer is equal to a refractive index of a contact portion of the multi-mode layer which is in contact with the transition layers disposed on the inner side of the multi-mode layer. A refractive index of an optional transition layer disposed on the outer side of the multi-mode layer is equal to a refractive index of an outer contact portion of the multi-mode layer which is in contact with the transition layer disposed on the outer side of the multi-mode layer.

Among the transition layers, a transition layer is disposed between the single-mode core and the multi-mode layer, which is also referred to as a first transition layer. As compared to pure silica, the first transition layer has a relative refractive index δ<NUM> of <NUM>% to <NUM>%. The first transition layer has a one-side width W<NUM> between <NUM> and <NUM>. The relative refractive index δ<NUM> of the first transition layer is lower than a relative refractive index δ<NUM> of the single-mode core, and equal to a refractive index of a contact portion of the multi-mode layer (i.e., the inner side of the multi-mode layer) which is in contact with the first transition layer. The difference is reduced, and meanwhile the viscosity of the precursor of the transition layer is between the viscosities of the single-mode core and of the multi-mode layer during pre-fabrication. Uniform drawing of a multilayer sandwich structure can thus be realized, which relieves the stress risers and large attenuation caused by a viscosity mismatch during the drawing process, and makes the new fiber have a lower loss characteristics.

Among the transition layers, a transition layer is disposed between the multi-mode layer and the outer cover layer, which is also referred to as a second transition layer. As compared to pure silica, the second transition layer has a relative refractive index δ<NUM> of -<NUM>% to <NUM> %. A one-side width W<NUM> of the second transition layer is between <NUM> and <NUM>. The relative refractive index δ<NUM> is equal to a refractive index of a contact portion of the multi-mode layer (i.e., the outer side of the multi-mode layer), ensuring that the multi-mode layer has a lower loss characteristics and reduced difficulties in molding.

The single-mode core is germanium-doped silica glass having a radius r<NUM> between <NUM> and <NUM>, and a relative refractive index δ<NUM> which is higher than the relative refractive index δ<NUM> of the first transition layer, δ<NUM>-δ<NUM>= <NUM>%~<NUM>%.

The multi-mode layer has a relative refractive index δ<NUM> which is between the relative refractive index δ<NUM> of the first transition layer and the relative refractive index δ<NUM> of the second transition layer, and is α-profile distributed. A radius r<NUM> of the multi-mode layer is between <NUM> and <NUM>. The α is between <NUM> and <NUM>.

The novel fiber has a radius r<NUM> of between <NUM> and <NUM>.

The outer cover layer is of pure silica glass.

According to the claimed invention, a lower doped layer of lower step index is disposed between the single-mode core and the multi-mode layer. A relative refractive index δ<NUM> of the lower doped layer is lower than the relative refractive index δ<NUM> of the first transition layer, and a one-side width W<NUM> of the lower doped layer is between <NUM> and <NUM>. δ<NUM>-δ<NUM>=-<NUM>% ~ -<NUM>%. In a specific embodiment, the lower doped layer includes a multi-layer structure disposed coaxially, among which a main lower doped layer has a lower step index, and the other layers are auxiliary lower doped layers. For example, the lower doped layer includes the main lower doped layer and an auxiliary lower doped layer. A width W<NUM> of a single layer of the main lower doped layer is between <NUM> and <NUM>, and δ<NUM>-δ<NUM>=-<NUM>%~-<NUM>%. A width W<NUM> of a single layer of the auxiliary lower doped layer is between <NUM> and <NUM>, and δ<NUM>-δ<NUM>=-<NUM>%~-<NUM>%.

In a specific embodiment, a recessed layer having a lower step index is included between the multi-mode layer and the outer cover. A relative refractive index δ<NUM> of the recessed layer is lower than the relative refractive index δ<NUM> of the second transition layer. The recessed layer has a one-sided width W<NUM> between <NUM> and <NUM>. The relative refractive index δ<NUM> is between -<NUM>% and -<NUM>%. The outer cover layer is of pure silica glass. In a specific embodiment, the recessed layer comprises a multi-layer structure disposed coaxially, among which a main recessed layer has a lower step index, and the other layers are auxiliary recessed layers. For example, the recessed layer includes the main recessed layer and an auxiliary recessed layer. A width W<NUM> of a single layer of the main recessed layer is between <NUM> and <NUM>, and a relative refractive index δ<NUM> of the main recessed layer is between -<NUM>% and -<NUM>%. A width W<NUM> of a single layer of the auxiliary recessed layer is between <NUM> and <NUM>, and a relative refractive index δ<NUM> of the auxiliary recessed layer is between -<NUM>% and -<NUM>%.

Example <NUM> not being covered by the claimed invention.

As shown in <FIG>, the novel optical fiber includes a single-mode core, a first transition layer, a multi-mode layer and an outer cover layer disposed coaxially from the inside to the outside. The single-mode core is located at a center of the optical fiber and has an upper step index. The multimode layer surrounds the first transition layer and has a refractive index of α-profile distribution. The single mode core has a radius r<NUM> of <NUM> and a relative refractive index δ<NUM> of <NUM>%. The first transition layer has a step index, and a one-side width W<NUM> of <NUM>. A relative refractive index δ<NUM> of the first transition layer is <NUM>%. The multi-mode layer has a radius r<NUM> of <NUM>. The α is <NUM>. The outer cover layer is of pure silica glass. A radius r<NUM> of the novel optical fiber is <NUM>. Main characteristics of the novel optical fiber are as follows: the mode field (@ <NUM>) diameter of the single-mode core is <NUM>, the cut-off wavelength of the optical fiber is <NUM>, and the over filled launch bandwidth of the multi-mode layer is <NUM>. km at a waveform of <NUM> and is <NUM>. km at a waveform of <NUM>.

As shown in <FIG>, the novel optical fiber includes a single-mode core, a first transition layer, a multi-mode layer, a second transition layer, and an outer cover layer coaxially disposed from the inside to the outside. The single-mode core is located at a center of the optical fiber and has an upper step index. The multi-mode layer is disposed between the first transition layer and the second transition layer, and has a refractive index of α-profile distribution. The single mode core has a radius r<NUM> of <NUM> and a relative refractive index δ<NUM> of <NUM>%. The first transition layer has a step index, and a one-side width W<NUM> of <NUM>. A relative refractive index δ<NUM> of the first transition layer is <NUM>%. The multi-mode layer has a radius r<NUM> of <NUM>. The α is <NUM>. The second transition layer has a step index, and a one-side width W<NUM> of <NUM>. A relative refractive index δ<NUM> of the second transition layer is -<NUM>%. The outer cover layer is of pure silica glass. A radius r<NUM> of the novel optical fiber is <NUM>. Main characteristics of the novel optical fiber are as follows: the mode field diameter of the single mode core is <NUM>, the cut-off wavelength of the novel optical fiber is <NUM>, and the over filled launch bandwidth of the multi-mode layer is <NUM>-km at a wavelength of <NUM> and is <NUM>-km at a wavelength of <NUM>.

As shown in <FIG>, the novel optical fiber includes a single-mode core, a lower doped layer, a first transition layer, a multi-mode layer and an outer layer coaxially disposed from the inside to the outside. The single-mode core is located at a center of the optical fiber and has an upper step index. The multi-mode layer surrounds the transition layer and has a refractive index of α-profile distribution. The single mode core has a radius r<NUM> of <NUM> and a relative refractive index δ<NUM> of <NUM>%. The lower doped layer has a one-side width W<NUM> of <NUM> and a relative refractive index δ<NUM> of <NUM>%. The first transition layer has a step index, and a one-side width W<NUM> of <NUM>. A relative refractive index δ<NUM> of the first transition layer is <NUM>%. The multi-mode layer has a radius r<NUM> of <NUM>. The α is <NUM>. The outer cover layer is of pure silica glass. A radius r<NUM> of the novel optical fiber is <NUM>. Main characteristics of the novel optical fiber are as follows: the mode field diameter of the single-mode core is <NUM> at a wavelength of <NUM>, and the cut-off wavelength of the optical fiber is <NUM>, and the over filled launch bandwidth of the multi-mode layer is <NUM>·km at a wavelength of <NUM>, and is <NUM>-km at a wavelength of <NUM>. The macrobend loss of the novel optical fiber when wound for <NUM> turns around a bend radius of <NUM> is <NUM> dB at a wavelength of <NUM> and is <NUM> dB at a wavelength of <NUM>.

As shown in <FIG>, the novel optical fiber includes a single-mode core, a lower doped layer, a first transition layer, a multi-mode layer, a second transition layer, and an outer cover layer coaxially disposed from the inside to the outside. The single-mode core is located at a center of the optical fiber and has an upper step index. The multi-mode layer is disposed between the first transition layer and the second transition layer, and has a refractive index of α-profile distribution. The single mode core has a radius r<NUM> of <NUM>, and a relative refractive index δ<NUM> of <NUM>%. A one-side width W<NUM> of the lower doped layer is <NUM> and a relative refractive index δ<NUM> of the lower doped layer is <NUM>%. The first transition layer has a step index, and a one-side width W<NUM> of <NUM>. A relative refractive index δ<NUM> of the first transition layer is <NUM>%. The multi-mode layer has a radius r<NUM> of <NUM>. The α is <NUM>. The second transition layer has a step index, and a one-side width W<NUM> of <NUM>. A relative refractive index δ<NUM> of the second transition layer is -<NUM>%. The cover layer is of pure silica glass. A radius r<NUM> of the novel optical fiber is <NUM>. Main characteristics of the novel optical fiber are as follows: the mode field diameter of the single mode core is <NUM> at a wavelength of <NUM>, the cut-off wavelength is <NUM>, and the over filled launch bandwidth of the multi-mode layer is <NUM>-km at a wavelength of <NUM> and is <NUM>-km at a wavelength of <NUM>. The macrobend loss of the novel optical fiber when wound for <NUM> turns around a bend radius of <NUM> is <NUM>. 067dB at <NUM>, and the fiber attenuation at <NUM> is about <NUM>.

As shown in <FIG>, the novel optical fiber includes a single-mode core, a first transition layer, a multi-mode layer, a second transition layer, a recessed layer, and an outer cover layer coaxially disposed from the inside to the outside. The single-mode core is located at a center of the optical fiber and has an upper step index. The multi-mode layer is disposed between the first transition layer and the second transition layer, and has a refractive index of α-profile distribution. The single mode core has a radius r<NUM> of <NUM>, and a relative refractive index δ<NUM> of <NUM>%. The first transition layer has a step index, and a one-side width W<NUM> of <NUM>. The relative refractive index δ<NUM> of the first transition layer is <NUM>%. A radius r<NUM> of the multi-mode layer is <NUM>. The α is <NUM>. The second transition layer has a step index, and a one-side width W<NUM> of <NUM>. A relative refractive index δ<NUM> of the second transition layer is <NUM>. A one-side width W<NUM> of the recessed layer is <NUM>, and a relative refractive index δ<NUM> of the recessed layer is -<NUM>%. The outer cover layer is of pure silica glass. A radius r<NUM> of the novel optical fiber is <NUM>. Main characteristics of the novel optical fiber are as follows: the over filled launch bandwidth of the multi-mode layer is <NUM>·km at a wavelength of <NUM> and is <NUM>-km at a wavelength of <NUM>.

As shown in <FIG>, the novel optical fiber includes a single-mode core, a first transition layer, a multi-mode layer, a second transition layer, a recessed layer, and an outer cover layer coaxially disposed from the inside to the outside. The single-mode core is located at a center of the optical fiber and has an upper step index. The multi-mode layer is disposed between the first transition layer and the second transition layer, and has a refractive index of α-profile distribution. The single mode core has a radius r<NUM> of <NUM>, and a relative refractive index δ<NUM> of <NUM>%. The first transition layer has a step index, and a one-side width W<NUM> is <NUM>. A relative refractive index δ<NUM> of the first transition layer is <NUM>%. The multi-mode layer has a radius r<NUM> of <NUM>,. The α is <NUM>. The second transition layer has a step index, and a one-side width W<NUM> of <NUM>. A relative refractive index δ<NUM> of the second transition layer is -<NUM>%. The recessed layer has a one-side width W<NUM> of <NUM>, and a relative refractive index δ<NUM> of - <NUM>%. The outer cover layer is of pure silica glass. A radius r<NUM> of the novel optical fiber is <NUM>.

As shown in <FIG>, the novel optical fiber includes a single-mode core, an auxiliary lower doped layer, a main lower doped layer, a first transition layer, a multi-mode layer, a second transition layer, a recessed layer and an outer cover layer coaxially disposed from the inside to the outside. The single-mode core is located at a center of the optical fiber and has an upper step index and a refraction index of α-profile distribution. The single mode core has a radius r<NUM> of <NUM> and a relative refractive index δ<NUM> of <NUM>%. A width W<NUM> of a single layer of the auxiliary lower doped layer is <NUM>, and a relative refractive index δ<NUM> is <NUM>%. A width W<NUM> of a single layer of the main lower doped layer is <NUM>, and the relative refractive index δ<NUM> of the main lower doped layer is <NUM>%. The first transition layer has a step index, and a one-side width W<NUM> of <NUM>. A relative refractive index δ<NUM> of the first transition layer is <NUM>%. The multi-mode layer has a radius r<NUM> of <NUM>. The α is <NUM>. The second transition layer has a step index, and a one-side width W<NUM> of <NUM>. A relative refractive index δ<NUM> of the second transition layer is <NUM>. A one-side width W<NUM> of the recessed layer is <NUM>, and the relative refractive index δ<NUM> of the recessed layer is -<NUM>%. The outer cover layer is of pure silica glass. A radius r<NUM> of the novel optical fiber is <NUM>. Main characteristics of the novel optical fiber are as follows: the macrobend loss when wound for <NUM> turns around a bend radius of <NUM> is <NUM> dB at a wavelength of <NUM> and is <NUM> dB at a wavelength of <NUM>.

As shown in <FIG>, the novel optical fiber includes a single-mode core, a first transition layer, a multi-mode layer, a second transition layer, a main recessed layer, an auxiliary recessed layer, and an outer cover layer disposed coaxially from the inside to the outside. The single-mode core is located at a center of the optical fiber and has an upper step index and a refractive index of α-profile distribution. The single-mode core has a radius r<NUM> of <NUM> and a relative refractive index δ<NUM> of <NUM>%. The first transition layer has a step index, and a one-side width W<NUM> of <NUM>. A relative refractive index δ<NUM> of the first transition layer is <NUM>%. A radius r<NUM> of the multi-mode layer is <NUM>. The α is <NUM>. The second transition layer has a step index, and a one-side width W<NUM> of <NUM>. A relative refractive index δ<NUM> of the second transition layer is -<NUM>%. A width W<NUM> of a single layer of the main recessed layer is <NUM>, and a relative refractive index δ<NUM> is of the main recessed layer -<NUM>%. A width W<NUM> of a single layer of the auxiliary recessed layer is <NUM>, and a relative refractive index δ<NUM> of the auxiliary recessed layer is -<NUM>%. The outer cover layer is of pure silica glass. A radius r<NUM> of the novel optical fiber is <NUM>. Main characteristics of the novel optical fiber are as follows: the macrobend loss when wound for <NUM> turns around a bend radius of <NUM> is <NUM> dB at <NUM> and is <NUM> dB at <NUM>.

The above embodiment shows that the single-mode core of the novel optical fiber of the present invention has a mode field diameter of <NUM> to <NUM>, and a cut-off wavelength of <NUM>-<NUM>. The over filled launch bandwidth of the multi-mode layer is <NUM>~<NUM>·km at a wavelength of <NUM> and is <NUM>~<NUM>-km at a wavelength of <NUM>. The macrobend loss of the optical fiber when wound for <NUM> turns around a bend radius of <NUM> is <NUM> to <NUM> dB at a wavelength of <NUM> and is <NUM> to <NUM> dB at a wavelength of <NUM>.

Claim 1:
A novel optical fiber comprising:
a single-mode core, a multi-mode layer and an outer cover layer coaxially disposed from the inside to the outside,
wherein:
the single-mode core is located at a center of the novel optical fiber and has a step index,
the multi-mode layer surrounds the single-mode core and has a refractive index of α-profile distribution,
a plurality of transition layers is disposed on an inner side and optionally an outer side of the multi-mode layer,
the transition layers are coaxial with the single-mode core and the outer cover layer,
the transition layers cling to the multi-mode layer,
a refractive index of a transition layer disposed on the inner side of the multi-mode layer is equal to a refractive index of an inner contact portion of the multi-mode layer which is in contact with the transition layer disposed on the inner side of the multi-mode layer,
a refractive index of an optional transition layer disposed on the outer side of the multi-mode layer is equal to a refractive index of an outer contact portion of the multi-mode layer which is in contact with the transition layer disposed on the outer side of the multi-mode layer;
a transition layer is disposed between the single-mode core and the multi-mode layer as a first transition layer, and as compared with pure silica, a relative refractive index δ<NUM> of the first transition layer is between <NUM>% and <NUM>%, and a one-side width W<NUM> of the first transition layer is between <NUM> and <NUM>;
when a transition layer is disposed between the multi-mode layer and the outer cover layer as a second transition layer, as compared to pure silica, a relative refractive index δ<NUM> of the second transition layer is between -<NUM>% and <NUM>%, and a one-side width W<NUM> of the second transition layer is between <NUM> and <NUM>;
the single-mode core is germanium-doped silica glass, has a radius r<NUM> of between <NUM> and
<NUM>, and a relative refractive index δ<NUM> which is higher than the relative refractive index δ<NUM> of the first transition layer, and δ<NUM>-δ<NUM>= <NUM>%~<NUM>%; and
the novel optical fiber further comprises a lower doped layer having a lower step index disposed between the single-mode core and the multi-mode layer, wherein a relative refractive index δ<NUM> of the lower doped layer is lower than the relative refractive index δ<NUM> of the first transition layer, a one-side width W<NUM> of the lower doped layer is between <NUM> and <NUM>, and δ<NUM>-δ<NUM>=-<NUM>% - -<NUM>%.