Hybrid optical amplifier

Abstract

To provide a hybrid optical amplifier.SOLUTION: A hybrid optical amplifier according to an embodiment may include an erbium-doped fiber amplifier (EDFA) including multiple EDFA stages. The hybrid optical amplifier may also include a Raman amplifier inserted between two EDFA stages.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION

[0001] Embodiments described in this disclosure relate to hybrid optical amplifiers. [Background technology]

[0002]

[0002] Telecommunications systems, cable television systems, and data communication networks use optical networks to convey information between remote points. In optical networks, information is conveyed in the form of optical signals through optical fibers or other optical media. Optical networks may include various components such as amplifiers, dispersion compensators, multiplexer / demultiplexer filters, wavelength selective switches, couplers, etc. configured to perform various operations within the optical network. Furthermore, optical amplification can be used to amplify optical signals propagating through the optical network.

[0003] The subject matter claimed herein is not limited to embodiments that solve any drawbacks or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one example technology area where any embodiments described herein may be practiced. Summary of the Invention

[0004] According to one aspect of the embodiment, the hybrid optical amplifier may include an erbium-doped fiber amplifier (EDFA) including multiple EDFA stages. The hybrid optical amplifier may also include a Raman amplifier inserted between two EDFA stages.

[0005]

[0005] The object and advantages of the embodiments will be realized and attained at least by the elements, features, and combinations particularly pointed out in the claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and exemplary and are not limitations of the invention as claimed. [Brief explanation of the drawings]

[0006]

[0006] Exemplary embodiments will now be described and explained with additional specificity and detail with the aid of the accompanying drawings. [Figure 1]

[0007] FIG. 1 illustrates an exemplary embodiment of a hybrid optical amplifier. [Figure 2]

[0008] FIG. 2 illustrates another exemplary embodiment of a hybrid optical amplifier. [Figure 3]

[0009] FIG. 3 illustrates another exemplary embodiment of a hybrid optical amplifier. [Figure 4]

[0010] FIG. 4 is a flow chart of an exemplary method for performing amplification on an optical signal using a hybrid optical amplifier. [Figure 5]

[0011] 5 illustrates a block diagram of an exemplary computing system that may be used with a hybrid optical amplifier, both configured in accordance with some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0007]

[0012] An optical network may include nodes that may be configured to communicate information with each other via optical signals carried by optical fibers. In some situations, amplification of the optical signals in the optical fibers can allow the optical signals to travel longer distances by compensating for losses that may affect the optical signals, such as degradation of the optical signals due to noisy channels in the optical network.

[0008]

[0013] Amplification of optical signals within optical networks may be performed using erbium-doped fiber amplifiers (EDFAs) in some instances. However, the gain profile of EDF amplifiers may depend on a given wavelength band. Therefore, EDFAs may be limited to providing consistent amplification for a given wavelength band. For example, EDF amplification may vary between the optical communications C-band (e.g., frequencies having wavelengths between approximately 1525 nanometers (nm) and 1565 nm), the optical communications L-band (e.g., frequencies having wavelengths between approximately 1565 nm and 1605 nm), and the optical communications S-band (e.g., frequencies having wavelengths between approximately 1485 nm and 1525 nm).

[0009]

[0014] Alternatively or additionally, some optical amplifiers may be configured to produce Raman gain as part of the amplification (referred to as "Raman amplifiers"). In some cases, Raman amplifiers may be able to provide broader bandwidth amplification than EDFAs. Thus, Raman amplifiers may be used for amplification outside the specific bandwidth of EDFAs. In particular, the amplification process of Raman amplifiers may be based on Raman scattering, in which an incident optical signal interacts with vibrational modes of the optical fiber, promoting the transfer of energy into signal photons. Such scattering may result in amplification of optical signals over a wide range of wavelengths. However, compared to EDFAs, Raman amplifiers may have poorer noise characteristics and / or poorer fiber nonlinear characteristics.

[0010]

[0015] Some optical systems perform optical amplification by placing a Raman amplifier in a separate segment of optical fiber either before or after the EDFA in an attempt to increase the overall amplification bandwidth (such Raman amplifiers are referred to in this disclosure as "discrete Raman amplifiers"). However, placing a discrete Raman amplifier before the EDFA can increase the amount of noise that can enter and be amplified by the EDFA, and therefore can result in poor noise-related performance. Furthermore, placing a discrete Raman amplifier immediately after the EDFA can result in increased nonlinear distortion generated by the discrete Raman amplifier due to the input signal of the discrete Raman amplifier having a relatively high signal power.

[0011]

[0016] In accordance with one or more embodiments of the present disclosure, a hybrid optical amplifier ("hybrid amplifier") can be configured to benefit from the positive aspects of using EDFAs and Raman amplifiers together while also reducing the negative effects. In particular, as described in detail in this disclosure, a hybrid amplifier may include an EDFA that includes multiple EDFA stages. Additionally or alternatively, a hybrid amplifier may include a separate Raman amplifier inserted between two EDFA stages. Such a configuration may reduce the amount of noise added by the Raman amplifier and reduce nonlinear effects that may be added by the Raman amplifier, while the Raman amplifier amplifies signals outside the EDFA bandwidth.

[0012]

[0017] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0013]

[0018] 1 illustrates an exemplary embodiment of a hybrid amplifier 102 ("hybrid amplifier 110") in accordance with at least one embodiment of the present disclosure. In general, hybrid amplifier 102 may be configured to amplify optical signal 104 to generate amplified optical signal 110. Hybrid amplifier 102 may be included in any suitable optical device or network.

[0014]

[0019] Optical signal 104 may include any optical signal configured to carry data. For example, optical signal 104 may include an optical signal generated by a light emitting diode (LED), such as a laser diode, and / or other similar optical signal having data modulated thereon. In some embodiments, optical signal 104 may be generated by a transmission source, such as an optical transmitter, configured to transmit data and / or information over an optical network.

[0015]

[0020] In some embodiments, optical signal 104 may comprise a wavelength division multiplexing (WDM) signal, which may include multiple beams, each corresponding to a different wavelength range. Additionally or alternatively, the different wavelength ranges may correspond to different optical signal communication bands.

[0016]

[0021] For example, in some embodiments, optical signal 104 may include a first sub-signal corresponding to a first wavelength range, a second sub-signal corresponding to a second wavelength range, a third sub-signal corresponding to a third wavelength range, and / or a fourth sub-signal corresponding to a fourth wavelength range. In some embodiments, the first wavelength range may correspond to what is commonly referred to as the C-band of optical signal communications, which may be approximately 1525 nm to 1565 nm. In these and other embodiments, the second wavelength range may correspond to what is commonly referred to as the L-band of optical signal communications, which may be approximately 1565 nm to 1605 nm. Additionally or alternatively, the third and fourth wavelength ranges may correspond to one or more bands that may be outside of the C-band or the L-band. For example, the third wavelength range may correspond to what is commonly referred to as the S-band of optical signal communications, which may be approximately 1485 nm to 1525 nm. Additionally or alternatively, the fourth wavelength range may correspond to what is commonly referred to as the U-band of optical signal communications, which may be approximately 1605 nm to 1645 nm.

[0017]

[0022] In these and other embodiments, optical signal 104 may have one or more polarization states. For example, in some embodiments, one or more sub-signals of optical signal 104 may be oriented according to a first polarization, and one or more sub-signals of optical signal 104 may be oriented according to a second polarization. In these and other embodiments, the first polarization may be orthogonal to the second polarization. For example, the first polarization may correspond to x-polarized light, and the second polarization may correspond to y-polarized light that is perpendicular to the x-polarized light.

[0018]

[0023] In some embodiments, the hybrid amplifier 102 includes a first EDFA stage 106a, a second EDFA stage 106b, and a third EDFA stage 106c, which may be collectively referred to as EDFAs 106 and / or EDFA stages. The EDFA stages 106 may be individually configured to provide gain to the optical signal 104, such that the power of the optical signal 104 may increase in a cumulative manner as the optical signal 104 passes through the EDFA stages 106.

[0019]

[0024] For example, the first EDFA stage 106a may be the first EDFA stage that receives and amplifies the optical signal 104. The second EDFA stage 106b may be the next EDFA stage after the first EDFA stage 106a and may apply additional amplification to the optical signal 104 after amplification by the first EDFA stage 106a. Additionally or alternatively, the third EDFA stage may be the next EDFA stage after the second EDFA stage 106b and may apply additional amplification to the optical signal 104 after amplification by the first EDFA stage 106a and the second EDFA stage 106b.

[0020]

[0025] The hybrid optical amplifier 102 may also include a separate Raman amplifier 108 ("Raman amplifier 108"). The Raman amplifier 108 may be inserted between two EDFA stages 106. For example, in some embodiments, the Raman amplifier 108 may be located between the first EDFA stage 106a and the second EDFA stage 106b.

[0021]

[0026] The Raman amplifier 108 may be configured to apply Raman gain to an optical signal that may be received by the Raman amplifier 108. For example, the Raman amplifier 108 may receive the optical signal 104 after the optical signal 104 has been amplified by the first EDFA stage 106a and apply the Raman effect to at least a portion of the received optical signal. In these and other embodiments, the Raman amplifier 108 may be configured to output the optical signal 104 to be amplified using the Raman effect and provide such signal as an input to the second EDFA stage 106b. In this manner, the optical signal 104 may be received by the second EDFA stage 106b after being amplified by both the first EDFA stage 106a and the Raman amplifier 108.

[0022]

[0027] In some embodiments, the Raman amplifier 108 may be configured to apply the Raman effect to all of the optical signal 104 received after amplification by the first EDFA stage 106a. Additionally or alternatively, the Raman amplifier 108 may be configured such that sub-signals of the optical signal 104 corresponding to particular wavelengths may bypass Raman amplification. For example, in some embodiments, the Raman amplifier 108 may be configured such that sub-signals of the optical signal corresponding to a first wavelength range and / or a second wavelength range (e.g., frequencies having wavelengths within the C-band and / or L-band) may bypass Raman amplification. Exemplary embodiments are described in further detail in this disclosure in connection with FIG. 3.

[0023]

[0028] In some examples, certain components used in Raman amplification (e.g., dispersion compensating optical fibers (DCF)) may be polarization-dependent, in that such components may affect signals having different polarizations differently. Accordingly, to help account for this in some embodiments, Raman amplifier 108 may include multiple stages, each of which may correspond to a different polarization. For example, Raman amplifier 108 may include a first Raman stage 108 a and a second Raman stage 108 b. In these and other embodiments, first Raman stage 108 a may correspond to a first polarization corresponding to optical signal 104, and second Raman stage 108 b may correspond to a second polarization corresponding to optical signal 104. Additional examples and details regarding Raman stages 108 are described further in this disclosure in connection with FIGS. 2 and 3.

[0024]

[0029] 1 may be modified, added, or omitted without departing from the scope of the present disclosure. For example, the Raman amplifier 108 may also be placed between another EDFA stage other than the lead EDFA and the next EDFA stage after the lead EDFA stage. However, as discussed above, it should be noted that the disadvantages associated with placing the Raman amplifier before the EDFA may increase the further downstream in the EDFA chain the Raman amplifier 108 is placed.

[0025]

[0030] Furthermore, the EDFA stages 106 may have similar configurations, and / or one or more of the EDFA stages 106 may be different. For example, as described in more detail below, in some embodiments, one or more of the EDFA stages 106 may include respective pump sources. In these and other embodiments, the wavelengths corresponding to two or more pump sources may be the same or different. The selection of different pump sources may be based on noise and / or gain profiles. Exemplary embodiments are described in more detail with respect to FIGS. 2 and 3.

[0026]

[0031] Additionally or alternatively, the hybrid amplifier 102 may be configured for a particular wavelength range. For example, in some embodiments, the hybrid amplifier 102 may be configured to provide amplification for frequencies corresponding to the C-band, L-band, and S-band, as described in connection with FIG. 2. Additionally or alternatively, the hybrid amplifier 102 may be configured to provide amplification for frequencies corresponding to only the S-band. In these and other embodiments, the hybrid amplifier 102 may be configured to provide amplification for one or more other frequencies (e.g., those corresponding to the U-band).

[0027]

[0032] FIG. 2 illustrates an exemplary embodiment of a hybrid optical amplifier 202 (“hybrid amplifier 202”) in accordance with at least one embodiment of the present disclosure. In general, the hybrid amplifier 202 may be configured to amplify an optical signal to generate an amplified optical signal, which may be an example of hybrid amplifier 102 of FIG. 1. In some embodiments, the optical signal may be a WDM signal having multiple sub-signals corresponding to different frequencies and corresponding wavelength ranges, such as optical signal 104 of FIG. 1. The hybrid amplifier 202 may be included in any suitable optical device or network. Additionally or alternatively, the hybrid amplifier 202 may be configured as a C-band, L-band, and S-band amplifier (“SCL amplifier”), as described in more detail below.

[0028]

[0033] In some embodiments, hybrid amplifier 202 may include a first EDFA stage 206a, a second EDFA stage 206b, and a third EDFA stage 206c, which may be collectively referred to as EDFA 206 and / or EDFA stage 206. EDFA 206 may represent an example implementation of EDFA 106 of FIG.

[0029]

[0034] The first EDFA stage 206a may be configured to receive an optical signal and direct the optical signal toward the first EDF 214a. The first EDF 214a may be an erbium-doped optical fiber embedded with erbium ions. The erbium ions may become excited by a pump beam, which may be injected into the first EDF 214a by the pump source 212a. When the erbium ions are excited by the pump beam, they absorb energy and move to a higher energy level. When these excited erbium ions return to their lower energy state, they release energy in the form of photons at longer wavelengths, which may therefore provide amplification to the optical signal traveling through the first EDF 214a.

[0030]

[0035] In some embodiments, the first EDF 214a may have a predetermined length that may correspond to a target amount of gain bandwidth and / or gain. The specific type of EDF (e.g., Er dopant concentration) may be such that for the same length of an EDF of a different type, the gain bandwidth and / or amount of gain may differ. Additionally or alternatively, the gain bandwidth and / or amount of gain may differ for different lengths and / or EDF types depending on the pump beam wavelength. Thus, such factors may be considered and / or modified to achieve the target amount of gain and / or achieve the target gain bandwidth. For example, in some embodiments, the first EDF 214a may have a length of 2.5 meters, which may be based on the target amount of amplification and EDF type for the first EDFA stage 206a.

[0031]

[0036] In some embodiments, the pump source 212a may include a light source generator that may be configured to generate a pump beam. For example, the pump source 212a may include a laser device that may be configured to generate and / or output a pump beam.

[0032]

[0037] The pump source 212a may be configured to generate a pump beam having a particular wavelength (also referred to as operating at a particular wavelength). The particular wavelength may be selected based on one or more amplification effects that may correspond to the given wavelength. For example, a pump beam corresponding to a 980 nm wavelength may have relatively good noise performance (e.g., may not produce much noise) but may provide more limited gain. In contrast, a pump beam corresponding to a 1480 nm wavelength may have poorer noise performance but may provide greater gain compared to the 980 nm wavelength. In the example of FIG. 2, the pump wavelength corresponding to the pump source 212a may be 980 nm, which may also be referred to as the pump source 212a operating at a 980 nm pump wavelength. Such a selection may be based on balancing the introduction of noise into the optical signal early in the amplification provided by the hybrid optical amplifier 202 and reducing the amount of noise that may be amplified by subsequent stages of the hybrid amplifier 202.

[0033]

[0038] In these and other embodiments, the pump source 212a can be configured such that the resulting pump beam can be a high power pump beam, for example, the pump beam can include at least 20 decibels per milliwatt (dBm) of power.

[0034]

[0039] Additionally or alternatively, in some embodiments, pump source 212a may be controlled using a computing system, such as the computing system described below in connection with Figure 5 of this disclosure. For example, the computing system may be used to control or select the wavelength corresponding to the pump beam.

[0035]

[0040] In some embodiments, the hybrid amplifier 202 may include a filter 216a. The filter 216a, in some embodiments, may include any suitable component configured to filter predetermined wavelengths. For example, in some cases, the amplification that may be provided by the first EDFA stage 206a may be substantially higher for sub-signals of the optical signal corresponding to a first wavelength range (e.g., C-band and / or L-band) than for sub-signals corresponding to a second wavelength range (e.g., S-band). In these and other embodiments, the filter 216a may be configured to filter more of the signals corresponding to the first wavelength range than the signals corresponding to the second wavelength range, helping to avoid gain saturation in the first wavelength range from being applied to the second wavelength range, which may limit gain.

[0036]

[0041] In some embodiments, filter 216a may be a static filter that may have a fixed frequency response. Reference to a "fixed frequency response" is meant to account for unintentional drift in the frequency response due to certain conditions and is intended to convey a frequency response that is not easily adjustable, and is not meant to refer to an absolutely stationary frequency response. Additionally or alternatively, filter 216a may be a dynamic filter that may have an adjustable frequency response. In some embodiments, one or more adjustment operations may be performed or directed by a computing system such as that described in connection with FIG. 5.

[0037]

[0042] Additionally or alternatively, the hybrid amplifier 202 may also include a separate Raman amplifier 208 ("Raman amplifier 208"). The Raman amplifier 208 may be located after the first EDFA stage 206a or before the second EDFA stage 206b, which may be the next EDFA after the first EDFA stage 206a. In this manner, the Raman amplifier 208 may be configured to apply amplification after the amplification provided by the first EDFA 206a but before the amplification provided by the second EDFA stage 206b.

[0038]

[0043] As mentioned above, the sub-signals corresponding to the second wavelength range may be amplified less by the first EDFA stage 206a (and / or less by one or more subsequent EDFA stages 206a) than the sub-signals corresponding to the first wavelength range. Thus, in the illustrated example of Figure 2, the hybrid amplifier 202 may be configured to pre-separate the sub-signals corresponding to the second wavelength range from the sub-signals corresponding to the first wavelength range, such that the first wavelength range bypasses amplification.

[0039]

[0044] For example, the hybrid amplifier 202 may include a demultiplexer 220. The demultiplexer 220 may be configured to separate one or more first sub-signals corresponding to a first wavelength range from one or more second sub-signals corresponding to a second wavelength range.

[0040]

[0045] Additionally or alternatively, hybrid amplifier 202 can include a first optical path 222 optically coupled to demultiplexer 220. First optical path 222 can bypass Raman amplifier 208. In these and other embodiments, first optical path 222 can be configured to receive the first sub-signal such that the first sub-signal bypasses amplification by Raman amplifier 208.

[0041]

[0046] Additionally or alternatively, the hybrid amplifier 202 may also include a second optical path 224 optically coupled to the demultiplexer 220. The second optical path 224 may be configured to receive the second sub-signal. Additionally or alternatively, the second optical path 224 may include the Raman amplifier 208 such that the Raman amplifier 208 receives and amplifies the second sub-signal.

[0042]

[0047] In the illustrated example, Raman amplifier 208 may include a first Raman stage 208 a and a second Raman stage 208 b. In these and other embodiments, first Raman stage 208 a may correspond to a first polarization, and second Raman stage 208 b may correspond to a second polarization.

[0043]

[0048] For example, the first Raman stage 208a may include a first DCF 226a, and the second Raman stage 208b may include a second DCF 226b (commonly referred to as "DCFs 226"). The first DCF 226a may be configured to provide a better gain profile for the first polarization than for the second polarization. Additionally or alternatively, the second DCF 226b may be configured to provide a better gain profile for the second polarization than for the first polarization.

[0044]

[0049] The first Raman stage 208a may include a first pump source 228a, and the second Raman stage 208b may include a second pump source 228b (commonly referred to as "pump source 228"). The pump source 228 may be configured to generate a pump beam in a manner similar to that described with respect to the pump source 212a. Additionally or alternatively, the pump beams generated by the first pump source 228a and the second pump source 228b, respectively, may be injected into the first DCF 226a and the second DCF 226b, respectively, to help provide Raman amplification within the DCFs 226.

[0045]

[0050] The pump sources 228 may be configured to generate each pump beam to have a specific wavelength. The specific wavelength may be selected based on one or more amplification effects that may correspond to the given wavelength. In some embodiments, the specific wavelengths corresponding to the pump sources 228 may be the same. Additionally or alternatively, the specific wavelengths corresponding to the pump sources 228 may be different. For example, as shown in FIG. 2, the first pump source 228a may correspond to a wavelength of 1400 nm, and the second pump source 228b may correspond to a wavelength of 1410 nm. In some embodiments, the difference in wavelengths may be to reduce interference between amplification of one polarization and amplification of the other polarization.

[0046]

[0051] 2, the first Raman stage 208a and the second Raman stage 208b may be arranged in a cascade manner, such that the second sub-signal can be amplified by the first Raman stage 208a and then by the second Raman stage 208b. The order of which polarization corresponds to which Raman stage 208 may vary depending on the particular implementation.

[0047]

[0052] In some embodiments, the hybrid amplifier 202 may include a multiplexer 230. The multiplexer 230 may be located after the Raman amplifier 208 as shown and may be optically coupled to the first optical path 222 and the second optical path 224. The multiplexer 230 may be configured to recombine the first sub-signal and the second sub-signal after amplification of the second sub-signal by the Raman amplifier 208.

[0048]

[0053] In the illustrated example, at this point, the recombined optical signal, which may be amplified by the first EDFA stage 206a and the Raman filter 208, may be received by the second EDFA stage 206b. The second EDFA stage 206b may include a second EDF 214b, which may be identical to or similar to the first EDF 214a of the first EDFA stage 206a. In these and other embodiments, the second EDF 214b may have substantially the same length as the first EDF 214a. Additionally or alternatively, the second EDF 214b may have a different length than the first EDF 214a. For example, the second EDF 214b may have a length of 3 meters, while the first EDF 214a may have a length of 2.5 meters. The difference in length may correspond to different target gains and / or gain bandwidths for the first EDFA stage 206a and the second EDFA stage 206b and / or may correspond to different types of EDF used for the two stages.

[0049]

[0054] In these and other embodiments, second EDFA stage 206b may include pump source 212b, which may be the same as or similar to pump source 212a. In some embodiments, the wavelength corresponding to pump source 212b may be the same as that corresponding to pump source 212a. For example, as shown, both pump source 212a and pump source 212b may generate respective pumping beams corresponding to 980 nm. Additionally or alternatively, the wavelengths corresponding to pump source 212a and pump source 212b may be different.

[0050]

[0055] In some embodiments, second EDFA stage 206b may include filter 216b. In some embodiments, filter 216b may be the same as or similar to filter 216a. Additionally or alternatively, filter 216b may differ from filter 216a in terms of its particular frequency response and / or tunability.

[0051]

[0056] After amplification by the second EDFA stage 206b, the optical signal may be received at the third EDFA stage 206. The third EDFA stage 206c may include a third EDF 214c, which may be the same as or similar to the first EDF 214a of the first EDFA stage 206a and the first EDF 214b of the second EDFA stage 206b. In these and other embodiments, the third EDF 214c may have substantially the same length as the first EDF 214a and the second EDF 214b. Additionally or alternatively, the third EDF 214c may have a different length than the first EDF 214a and the second EDF 214b.

[0052]

[0057] For example, the third EDF 214c may have a length of 5 meters, while the first EDF 214a may have a length of 2.5 meters and the second EDF 214b may have a length of 3 meters. The difference in length may correspond to a different target gain and / or gain bandwidth for the third EDFA stage 206c compared to the other EDFA stages 206a, a different type of EDF used for the different EDFA stages, and / or different pump wavelengths used for the different EDFA stages.

[0053]

[0058] In these and other embodiments, third EDFA stage 206c may include pump source 212c, which may be similar or equivalent to pump sources 212a and 212b. In some embodiments, the wavelength corresponding to pump source 212c may be the same as that corresponding to pump source 212a and / or pump source 212b. Additionally or alternatively, the wavelength corresponding to pump source 212c may be different from the wavelengths of pump source 212a and / or pump source 212b. For example, as shown, pump source 212a and pump source 212b may both generate respective pump beams corresponding to 980 nm, while pump source 212c may generate a pump beam corresponding to 1480 nm. In some embodiments, 1480 nm may be selected for the pump beam due to the increased gain that may be provided. Furthermore, by using 1480 nm in the final EDFA stage, any extra noise that may be associated with the 1480 nm pump beam may be less of an issue because no further amplification by the hybrid amplifier 202 may be provided.

[0054]

[0059] In some embodiments, the hybrid amplifier 202 may include a gain equalizing filter 232 configured to receive the optical signal after amplification by the third EDFA stage 206 c. The gain equalizing filter 232 may include any suitable component configured to filter the optical signal such that the power of the optical signal across different communication bands (e.g., C-band, L-band, and S-band) is substantially the same. The signal output after the gain equalizing filter 232 may be an amplified version of the signal received at the first EDFA stage 206 a, passed through the first EDFA stage 206 a, then the Raman amplifier 208, then the second EDFA stage 206 b, then the third EDFA stage 206 c, and cumulatively amplified by the hybrid optical amplifier 202.

[0055]

[0060] In some embodiments, gain equalization filter 232 may be a static filter, which may have a fixed frequency response. Additionally or alternatively, gain equalization filter 232 may be a dynamic filter, which may have an adjustable frequency response. In some embodiments, one or more adjustment operations may be performed or directed by a computing system, such as the one described in connection with FIG. 5.

[0056]

[0061] Modifications, additions, or omissions may be made to the hybrid amplifier 202 without departing from the scope of the present disclosure. For example, the number of EDFA stages 206 may vary. Furthermore, the placement of the Raman amplifiers 208 and / or the number of Raman amplifiers 208 may vary. Furthermore, the hybrid amplifier 202 may include one or more other components that assist in facilitating the propagation and / or manipulation of the optical signal to achieve a target amount of gain. Furthermore, the wavelengths corresponding to different pump sources, the particular type of optical fiber used, and / or the lengths of the different optical fibers may vary depending on the particular implementation and design goals.

[0057]

[0062] FIG. 3 illustrates an exemplary embodiment of a hybrid optical amplifier 302 (“hybrid amplifier 302”) in accordance with at least one embodiment of the present disclosure. In general, the hybrid amplifier 302 may be configured to amplify an optical signal to generate an amplified optical signal, which may be another implementation of the hybrid amplifier 102 of FIG. 1. In some embodiments, the optical signal may be a WDM signal having multiple sub-signals corresponding to different frequencies and corresponding wavelength ranges, such as the optical signal 104 of FIG. 1. The hybrid amplifier 302 may be included in any suitable optical device or network. Additionally or alternatively, the hybrid amplifier 302 may be configured as an S-band amplifier, as described in more detail below.

[0058]

[0063] In some embodiments, the hybrid amplifier 302 may include a first EDFA stage 306a, a second EDFA stage 306b, and a third EDFA stage 306c, which may be collectively referred to as the EDFA 306 and / or the EDFA stages 306. The EDFA 306 may represent another example implementation of the EDFA 106 of FIG. 1. Additionally, the hybrid amplifier may include a separate Raman amplifier 308 (“Raman amplifier 308”) disposed between the first EDFA stage 306a and the second EDFA stage 306b.

[0059]

[0064] The first EDFA stage 306a may be substantially similar to the first EDFA stage 206a of FIG. 2. For example, the first EDFA stage 306a may include a pump source 312a that is substantially similar to or similar to the pump source 212a of FIG. 2 and an EDF 314a that is substantially similar to or similar to the first EDF 214a of FIG. 2. Furthermore, the first EDFA stage 306a may include a filter 316a that is substantially similar to or similar to the filter 216a of FIG. 2. However, in this exemplary embodiment, a difference between the filter 316a and the filter 216a is that the filter 316a may be configured to filter frequencies higher than those corresponding to the S-band (e.g., frequencies corresponding to the C-band and the L-band). As a result, frequencies corresponding to the C-band and the L-band may not pass through the second EDFA stage 306b. Note that a reference to not passing the C-band and the L-band does not necessarily mean that any portions of these bands are not passed. Rather, such a reference indicates that these bands are sufficiently attenuated by the target amount.

[0060]

[0065] The Raman amplifier 308 may provide additional amplification to the optical signal after amplification by the first EDFA stage 306a and after passing through filter 316a. In the illustrated example of Figure 3, the hybrid amplifier 302 may not include separate optical paths such as optical paths 222 and 224 in Figure 2 because the C-band and L-band are already filtered. Thus, the entire optical signal passing through filter 316a may be received at the Raman amplifier 308 in the illustrated example.

[0061]

[0066] The Raman amplifier 308 may be substantially similar to or similar to the Raman filter 208 of Figure 2. For example, in some embodiments, the Raman amplifier 308 may include a first Raman stage 308a that is substantially similar to or similar to the first Raman stage 208a of Figure 2. For example, the first Raman stage 308a may include a first DCF 326a that is substantially similar to or similar to the first DCF 226a of the first Raman stage 208a of Figure 2. Additionally or alternatively, the first Raman stage 308a may include a first pump source 328a that is substantially similar to or similar to the first pump source 228a of the first Raman stage 208a of Figure 2.

[0062]

[0067] Further, Raman amplifier 308 may include a second Raman stage 308b that is substantially similar to or similar to second Raman stage 208b of Figure 2. For example, second Raman stage 308a may include a second DCF 326b that is substantially similar to or similar to second DCF 226b of second Raman stage 208b of Figure 2. Additionally or alternatively, second Raman stage 308b may include a second pump source 328a that is substantially similar to or similar to second pump source 228b of second Raman stage 208b of Figure 2.

[0063]

[0068] The second EDFA stage 306b may be substantially similar to the second EDFA stage 206b of Figure 2. For example, the second EDFA stage 306b may include a pump source 312b that is substantially similar to or similar to the pump source 212b of Figure 2 and an EDF 314b that is substantially similar to or similar to the second EDF 214b of Figure 2. Further, the second EDFA stage 306b may include a filter 316b that is substantially similar to or similar to the filter 216b of Figure 2. However, similar to filter 316a compared to filter 216a, a difference between filter 316b and filter 216b may be that filter 316b may be configured to filter frequencies higher than those corresponding to the S-band.

[0064]

[0069] The third EDFA stage 306c may be substantially similar to or similar to the third EDFA stage 206c of Figure 2. For example, the third EDFA stage 306c may include a pump source 312c that is substantially similar to or similar to the pump source 212c of Figure 2 and an EDF 314c that is substantially similar to or similar to the third EDF 214c of Figure 2.

[0065]

[0070] In these and other embodiments, the hybrid optical amplifier 302 may include a gain equalizing filter 332 that is substantially similar or equivalent to the gain equalizing filter 232 of Figure 2. However, the specific frequency response of the gain equalizing filter 332 may differ from the frequency response of the gain equalizing filter 232 based on the hybrid amplifier 302 being configured as an S-band amplifier rather than an SCL-band amplifier as in Figure 2. The signal output after the gain equalizing filter 332 may be an amplified version of the signal received by the first EDFA stage 306a, passed through the first EDFA stage 306a, then the Raman amplifier 308, then the second EDFA stage 306b, then the third EDFA stage 306c, and cumulatively amplified by the hybrid optical amplifier.

[0066]

[0071] Modifications, additions, or omissions may be made to the hybrid amplifier 302 without departing from the scope of the present disclosure. For example, the number of EDFA stages 306 may vary. Furthermore, the placement of the Raman amplifiers 308 and / or the number of Raman amplifiers 308 may vary. Furthermore, the hybrid amplifier 302 may include one or more other components that assist in facilitating the propagation and / or manipulation of the optical signal to achieve a target amount of gain. Furthermore, the wavelengths corresponding to different pump sources, the particular type of optical fiber used, and / or the lengths of the different optical fibers may vary depending on the particular implementation and design goals.

[0067]

[0072] 4 is a flowchart of an example method 400 of performing amplification on an optical signal using a hybrid optical amplifier configured in accordance with at least one embodiment of the present disclosure. One or more operations of method 400 may be performed by any suitable element of a hybrid EDFA / Raman optical amplifier, such as hybrid amplifier 102 of FIG. 1, hybrid amplifier 202 of FIG. 2, and / or hybrid amplifier 102 of FIG. 3. Although shown as separate steps, various steps of method 400 may be divided into additional steps, combined into fewer steps, or eliminated, depending on the desired implementation. Furthermore, the order in which various steps are performed may vary depending on the desired implementation.

[0068]

[0073] In some embodiments, method 400 may include block 402. In block 402, an optical signal may be received at a hybrid optical amplifier. Optical signal 104 in FIG. 1 is an example of an optical signal, and hybrid amplifier 102 in FIG. 1, hybrid amplifier 202 in FIG. 2, or hybrid amplifier 302 in FIG. 3 may be examples of a hybrid amplifier.

[0069]

[0074] In block 404, the optical signal may be amplified using a first erbium-doped fiber amplifier (EDFA) stage of an EDFA included in a hybrid optical amplifier. First EDFA stage 106a in Figure 1, first EDFA stage 206a in Figure 2, and first EDFA stage 306a in Figure 3 are examples of first EDFA stages.

[0070]

[0075] In block 406, the optical signal may be amplified using a Raman amplifier included in a hybrid optical amplifier. Amplifying using a Raman amplifier may occur after amplifying the optical signal using a first EDFA stage, as described above in connection with one or more of Figures 1-3. Raman amplifier 108 of Figure 1, Raman amplifier 208 of Figure 2, and Raman amplifier 308 of Figure 3 are examples of Raman amplifiers.

[0071]

[0076] In some embodiments, the Raman amplifier may include a first Raman stage configured to accommodate a first polarization and a second Raman stage configured to accommodate a second polarization, as described above with respect to one or more of Figures 1 through 3. Additionally or alternatively, in some embodiments, the first Raman stage may include a first pump source, and the second Raman stage may include a second pump source operating at a different pumping wavelength than the first pump source.

[0072]

[0077] At block 408, the optical signal may be amplified using a second EDFA stage of the EDFA. Amplifying the optical signal using the second EDFA stage may be performed after amplifying the optical signal using a Raman amplifier. In some embodiments, the first EDFA stage is the first EDFA stage of the EDFA, and the second EDFA stage is the next EDFA stage of the EDFA after the first EDFA stage.

[0073]

[0078] Modifications, additions, or omissions may be made to method 400 without departing from the scope of the present disclosure. For example, one skilled in the art will understand that the functions and / or operations performed with respect to this and other processes, operations, and methods disclosed herein may be performed in a different order. Furthermore, the described functions and operations are provided by way of example only, and some functions and operations may be optional, combined into fewer functions and operations, or expanded into additional functions and operations without detracting from the essence of the disclosed embodiments.

[0074]

[0079] Additionally or alternatively, in some embodiments, the EDFA may include more EDFA stages than a first EDFA stage and a second EDFA stage. For example, in some embodiments, method 400 may include amplifying the optical signal using a third EDFA stage of the EDFA after amplifying the optical signal using the second EDFA stage. Additionally or alternatively, the EDFA stages may include pump sources configured to operate at predetermined pump wavelengths. For example, the first EDFA stage may include a first pump source operating at a first pump wavelength, and the second EDFA stage may include a second pump source operating at a second pump wavelength. In some embodiments, the first pump wavelength and the second pump wavelength may be the same, while in other embodiments, the first pump wavelength and the second pump wavelength may be different. Additionally or alternatively, in embodiments in which the EDFA includes a third EDFA stage, the third EDFA stage may include a third pump source operating at a third pump wavelength. In some embodiments, the third pump wavelength may be the same as one or more of the first pump wavelength or the second pump wavelength. Additionally or alternatively, the third pump wavelength may be different from both the first pump wavelength and the second pump wavelength.

[0075]

[0080] In these and other embodiments, the method may include other operations, such as separating a first optical signal corresponding to a first wavelength range from a second optical signal corresponding to a second wavelength range. In some embodiments, separating a first sub-signal from a second sub-signal by a demultiplexer 220 as described with respect to FIG. 2 may be an example of separating.

[0076]

[0081] The operations may further include bypassing amplification of the first optical signal using a Raman amplifier. For example, using first optical path 222 to bypass amplification of the first sub-signal by Raman amplifier 208, bypassing Raman amplifier 202 in FIG. 2, may be an example of bypassing amplification of the first optical signal.

[0077]

[0082] Additionally or alternatively, the operation may include amplifying the second optical signal using a Raman amplifier. For example, including Raman amplifier 202 of FIG. 2 in second optical path 224 to amplify the second sub-signal with Raman amplifier 208 may be an example of amplifying the second optical signal.

[0078]

[0083] In these and other embodiments, the operation may include recombining the first and second optical signals after amplifying the second optical signal using a Raman amplifier. In some embodiments, combining the first sub-signal with the second sub-signal by multiplexer 230 as described with respect to FIG. 2 may be an example of combining.

[0079]

[0084] 5 is a block diagram of an example computing system 502 that may be used in connection with a hybrid optical amplifier in accordance with at least one embodiment of the present disclosure. For example, the computing system 502 may be used to adjust the pumping wavelength of a pump source (e.g., one or more of the pump sources described above in connection with FIGS. 1, 2, and 3) of the hybrid optical amplifier and / or the frequency response of a filter (e.g., one or more of the filters described above in connection with FIGS. 1, 2, and 3) of the hybrid optical amplifier.

[0080]

[0085] The computing system 502 may include a processor 550, a memory 552, and storage 554. The processor 550, the memory 552, and the storage 554 may be communicatively coupled.

[0081]

[0086] Generally, processor 550 may include any suitable special-purpose or general-purpose computer, computing entity, or processing device, including various computer hardware or software modules, and may be configured to execute instructions stored on any applicable computer-readable storage medium. For example, processor 550 may include a microprocessor, microcontroller, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or any other digital or analog circuit configured to interpret and / or execute program instructions and / or process data. Although shown as a single processor in FIG. 5, processor 550 may include any number of processors configured to individually or collectively perform or direct the execution of any number of operations described in this disclosure. Additionally, one or more processors may reside on one or more different electronic devices, such as different servers.

[0082]

[0087] In some embodiments, processor 550 may be configured to interpret and / or execute program instructions and / or process data stored in memory 552, data storage 554, or memory 552 and data storage 554. In some embodiments, processor 550 may fetch program instructions from data storage 554 and load the program instructions into memory 552. After the program instructions are loaded into memory 552, processor 550 may execute the program instructions.

[0083]

[0088] Memory 552 and data storage 554 may include computer-readable storage media that carry or have computer-executable instructions or data structures stored thereon. Such computer-readable storage media may include any available media that can be accessed by a general-purpose or special-purpose computer, such as processor 550. By way of example, and not limitation, such computer-readable storage media may include tangible or non-transitory computer-readable storage media, including random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), compact disk read-only memory (CD-ROM) or other optical disk storage, magnetic disk storage or other magnetic storage devices, flash memory devices (e.g., solid-state memory devices), or any other storage medium that can be used to store specific program code in the form of computer-executable instructions or data structures and that can be accessed by a general-purpose or special-purpose computer. Combinations of the above may also be included within the scope of computer-readable storage media. Computer-executable instructions may comprise, for example, instructions and data configured to cause processor 550 to perform a particular operation or group of operations.

[0084]

[0089] Modifications, additions, or omissions may be made to computing system 502 without departing from the scope of the present disclosure. For example, in some embodiments, computing system 502 may include any number of other components that may not be explicitly shown or described.

[0085]

[0090] The terms used in this disclosure, and particularly in the appended claims (e.g., the body of the appended claims), are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including, but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "including, but not limited to," etc.).

[0086]

[0091] Furthermore, where a specific number recited in an introduced claim is intended, such intention will be expressly recited in the claim; absent such recitation, no such intention exists. For example, to facilitate understanding, the following appended claims may include the use of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to mean that introducing a claim recitation with the indefinite article "a" or "an" limits any particular claim that includes such an introduced claim recitation to embodiments containing only one such recitation, even if the same claim includes the introductory phrases "one or more" or "at least one" and an indefinite article term such as "a" (e.g., "a" and / or "an" should be construed to mean "at least one" or "one or more"); the same is true when using definite article terms used to introduce claim recitations.

[0087]

[0092] Also, even when a specific number of recitations in a claim is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the unmodified recitation of "two recitations" without other modifiers means at least two recitations or more than two recitations). Furthermore, when usage similar to "such as at least one of A, B, and C" or "such as one or more of A, B, and C" is used, generally, such configuration is intended to include A only, B only, C only, A and B together, A and C together, B and C together, or A, B, and C together, etc. Note that use of the term "and / or" is intended to be structured in this manner.

[0088]

[0093] Furthermore, any disjunction or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibility of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" should be understood to include the possibilities of "A" or "B" or "A and B," even if the term "and / or" is used elsewhere.

[0089]

[0094] All examples and conditional language set forth in this disclosure are intended for educational purposes to assist the reader in understanding the concepts contributed by the inventors to further the disclosure and technology, and should be construed as without limitation to such specifically described examples and conditions. Although embodiments of the present disclosure have been described in detail, various changes, substitutions, and alterations can be made thereto without departing from the spirit and scope of the present disclosure.

[0090] In addition to the above description, the following notes are also provided.

[0091] (Appendix 1) 1. A hybrid optical amplifier comprising: an erbium-doped fiber amplifier (EDFA) including multiple EDFA stages; and a Raman amplifier inserted between two EDFA stages of the plurality of EDFA stages; A hybrid optical amplifier comprising:

[0092] (Appendix 2) 2. The hybrid optical amplifier according to claim 1, wherein the Raman amplifier is inserted between a leading EDFA stage among the plurality of EDFA stages and a next EDFA stage among the plurality of EDFA stages that immediately follows the leading EDFA stage.

[0093] (Appendix 3) 10. The hybrid optical amplifier of claim 1, wherein the Raman amplifier includes a first Raman stage configured to accommodate a first polarization and a second Raman stage configured to accommodate a second polarization.

[0094] (Appendix 4) 4. The hybrid optical amplifier of claim 3, wherein the first Raman stage includes a first pump source and the second Raman stage includes a second pump source operating at a pumping wavelength different from that of the first pump source.

[0095] (Appendix 5) 10. The hybrid optical amplifier of claim 1, wherein a final EDFA stage of the plurality of EDFA stages includes a first pump source operating at a first pump wavelength different from a second pump wavelength corresponding to a second pump source, each of the second pump sources corresponding to another EDFA stage of the plurality of EDFA stages.

[0096] (Appendix 6) 6. The hybrid optical amplifier of claim 5, wherein the first pump wavelength corresponds to better noise characteristics than the second pump wavelength, and the second pump wavelength corresponds to better gain characteristics than the first pump wavelength.

[0097] (Appendix 7) 2. The hybrid optical amplifier of claim 1, further comprising: a demultiplexer configured to separate a first optical signal corresponding to a first wavelength range from a second optical signal corresponding to a second wavelength range; a first optical path optically coupled to the demultiplexer, the first optical path bypassing the Raman amplifier and configured to receive the first optical signal; a second optical path optically coupled to the demultiplexer, the second optical path including the Raman amplifier, the second optical path configured to receive a second sub-signal and amplify the second optical signal with the Raman amplifier; and a multiplexer disposed after the Raman amplifier and optically coupled to the first optical path and the second optical path, the multiplexer configured to recombine the first optical signal and the second optical signal after second amplification by the Raman amplifier; A hybrid optical amplifier comprising:

[0098] (Appendix 8) 8. The hybrid optical amplifier of claim 7, wherein the first wavelength range includes one or more of an optical communications C-band or an optical communications L-band.

[0099] (Appendix 9) 8. The hybrid optical amplifier of claim 7, wherein the second wavelength range includes the S-band of optical communications.

[0100] (Appendix 10) 10. The hybrid optical amplifier of claim 1, wherein the one or more EDFA stages each include a filter configured to filter optical signals corresponding to a wavelength range that includes one or more of the optical telecommunications C-band or the optical telecommunications L-band.

[0101] (Appendix 11) receiving an optical signal at a hybrid optical amplifier; amplifying the optical signal using a first erbium-doped fiber amplifier (EDFA) stage of an EDFA included in the hybrid optical amplifier; amplifying the optical signal using a Raman amplifier included in the hybrid optical amplifier, wherein amplifying using the Raman amplifier occurs after amplifying the optical signal using a first EDFA stage; and amplifying the optical signal using a second EDFA stage of the EDFA after amplifying the optical signal using a Raman amplifier; A method comprising:

[0102] (Appendix 12) 12. The method of claim 11, wherein the first EDFA stage is the first EDFA stage of the EDFA, and the second EDFA stage is the next EDFA stage of the EDFA after the first EDFA stage.

[0103] (Appendix 13) 12. The method of claim 11, wherein the Raman amplifier includes a first Raman stage configured to accommodate a first polarization and a second Raman stage configured to accommodate a second polarization.

[0104] (Appendix 14) 14. The method of claim 13, wherein the first Raman stage includes a first pump source and the second Raman stage includes a second pump source operating at a different pumping wavelength than the first pump source.

[0105] (Appendix 15) 12. The method of claim 11, further comprising, after amplifying the optical signal with the second EDFA stage, amplifying the optical signal with a third EDFA stage of the EDFA.

[0106] (Appendix 16) 15. The method according to claim 14, wherein: the first EDFA stage includes a first pump source operating at a first pumping wavelength; the second EDFA stage includes a second pump source operating at a second pump wavelength that is the same as the first pump wavelength; and The method, wherein the third EDFA stage includes a second pump source operating at a third pump wavelength different from the first pump wavelength and the second pump wavelength.

[0107] (Appendix 17) 11. The method according to claim 10, wherein: Separating a first optical signal corresponding to a first wavelength range from a second optical signal corresponding to a second wavelength range; bypassing amplifying the first optical signal using the Raman amplifier; amplifying the second optical signal using the Raman amplifier; and recombining the first optical signal and the second optical signal after amplification of the second optical signal using the Raman amplifier; A method comprising:

[0108] (Appendix 18) 18. The method of claim 17, wherein the first wavelength range includes one or more of an optical communications C-band or an optical communications L-band.

[0109] (Appendix 19) 18. The method of claim 17, wherein the second wavelength range comprises the optical communications S-band.

[0110] (Appendix 20) 12. The method of claim 11, wherein one or more of the first EDFA stage or the second EDFA stage includes a filter configured to filter optical signals corresponding to a wavelength range including one or more of an optical communications C-band or an optical communications L-band, respectively. [Explanation of symbols]

[0111] 102 Hybrid Optical Amplifier 104 Optical Signal 106 EDFA 108 Separate Raman Amplifier

Claims

1. 1. A hybrid optical amplifier comprising: an erbium-doped fiber amplifier (EDFA) including multiple EDFA stages; and a Raman amplifier inserted between two EDFA stages of the plurality of EDFA stages; A hybrid optical amplifier comprising:

2. 2. The hybrid optical amplifier according to claim 1, wherein the Raman amplifier is inserted between a leading EDFA stage of the plurality of EDFA stages and a next EDFA stage of the plurality of EDFA stages that immediately follows the leading EDFA stage.

3. 10. The hybrid optical amplifier of claim 1, wherein the Raman amplifier includes a first Raman stage configured to accommodate a first polarization and a second Raman stage configured to accommodate a second polarization.

4. 4. The hybrid optical amplifier of claim 3, wherein the first Raman stage includes a first pump source and the second Raman stage includes a second pump source operating at a pumping wavelength different from that of the first pump source.

5. 2. The hybrid optical amplifier of claim 1, wherein a final EDFA stage of the plurality of EDFA stages includes a first pump source operating at a first pump wavelength different from second pump wavelengths corresponding to second pump sources, each of the second pump sources corresponding to another EDFA stage of the plurality of EDFA stages.

6. 6. The hybrid optical amplifier of claim 5, wherein the first pump wavelength corresponds to better noise characteristics than the second pump wavelength, and the second pump wavelength corresponds to better gain characteristics than the first pump wavelength.

7. 10. The hybrid optical amplifier of claim 1, further comprising: a demultiplexer configured to separate a first optical signal corresponding to a first wavelength range from a second optical signal corresponding to a second wavelength range; a first optical path optically coupled to the demultiplexer, the first optical path bypassing the Raman amplifier and configured to receive the first optical signal; a second optical path optically coupled to the demultiplexer, the second optical path including the Raman amplifier, the second optical path configured to receive a second sub-signal and amplify the second optical signal with the Raman amplifier; and a multiplexer disposed after the Raman amplifier and optically coupled to the first optical path and the second optical path, the multiplexer configured to recombine the first optical signal and the second optical signal after second amplification by the Raman amplifier; A hybrid optical amplifier comprising:

8. 8. The hybrid optical amplifier of claim 7, wherein the first wavelength range includes one or more of the optical telecommunications C-band or the optical telecommunications L-band.

9. 8. The hybrid optical amplifier of claim 7, wherein the second wavelength range includes the optical communications S-band.

10. 10. The hybrid optical amplifier of claim 1, wherein one or more EDFA stages each include a filter configured to filter optical signals corresponding to a wavelength range including one or more of the optical communications C-band or the optical communications L-band.

11. receiving an optical signal at a hybrid optical amplifier; amplifying the optical signal using a first erbium-doped fiber amplifier (EDFA) stage of an EDFA included in the hybrid optical amplifier; amplifying the optical signal using a Raman amplifier included in the hybrid optical amplifier, wherein amplifying using the Raman amplifier occurs after amplifying the optical signal using a first EDFA stage; and amplifying the optical signal using a second EDFA stage of the EDFA after amplifying the optical signal using a Raman amplifier; A method comprising:

12. 12. The method of claim 11, wherein the first EDFA stage is a leading EDFA stage of the EDFA, and the second EDFA stage is a next EDFA stage of the EDFA after the first EDFA stage.

13. 12. The method of claim 11, wherein the Raman amplifier includes a first Raman stage configured to accommodate a first polarization and a second Raman stage configured to accommodate a second polarization.

14. 14. The method of claim 13, wherein the first Raman stage includes a first pump source and the second Raman stage includes a second pump source operating at a different pumping wavelength than the first pump source.

15. 12. The method of claim 11, further comprising the step of amplifying the optical signal with a third EDFA stage of the EDFA after amplifying the optical signal with the second EDFA stage.

16. 16. The method of claim 15, wherein: the first EDFA stage includes a first pump source operating at a first pumping wavelength; the second EDFA stage includes a second pump source operating at a second pump wavelength that is the same as the first pump wavelength; and The method, wherein the third EDFA stage includes a second pump source operating at a third pump wavelength different from the first pump wavelength and the second pump wavelength.

17. 12. The method of claim 11 : Separating a first optical signal corresponding to a first wavelength range from a second optical signal corresponding to a second wavelength range; bypassing amplifying the first optical signal using the Raman amplifier; amplifying the second optical signal using the Raman amplifier; and recombining the first optical signal and the second optical signal after amplification of the second optical signal using the Raman amplifier; A method comprising:

18. 20. The method of claim 17, wherein the first wavelength range includes one or more of the optical telecommunications C-band or the optical telecommunications L-band.

19. 20. The method of claim 17, wherein the second wavelength range comprises the optical communications S-band.

20. 12. The method of claim 11, wherein one or more of the first EDFA stage or the second EDFA stage each includes a filter configured to filter optical signals corresponding to a wavelength range including one or more of an optical communications C-band or an optical communications L-band.

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