Patent Description:
The following relates to optical communication transceivers, including gimballess quasi-omni optical communication transceivers.

An optical transceiver may include an optical transmitter and an optical receiver. In some examples, the optical transceiver may be placed on a gimbal to enable coarse-pointing for and/or for actuating the optical transceiver. An omni-directional laser communication system is intended eliminate a usage of precision beam-pointing, which may streamline certain application scenarios. Additionally, as a size or weight of the optical transceiver increases, the ease with which the optical transceiver may be actuated may decrease. Accordingly, techniques that simplify laser beam pointing and/or maintain or reduce a size or weight of the optical transceiver in applications in which the optical transceiver is mobile may be desired.

<CIT> discloses a wireless optical communication receiver is provided.

<CIT> discloses a fluorescent activated light detector for detection of time modulated infrared signals of preselected wavelength.

An optical transceiver may include an optical transmitter and an optical receiver, where the optical transmitter may be configured to convey information by transmitting light (for example, via lasers) and the optical receiver may be set up to receive information by receiving the transmitted light. In mobile applications, it may be advantageous to simplify laser beam pointing to a target, which may present challenges for optical wireless communications systems, as failure to accurately point laser beams may result in failure to receive the light or failure to retrieve the correct information from the light. Additionally or alternatively, it may be advantageous to decrease a size or a weight of an assembly including the optical transceiver. One method of doing so may involve removing a gimbal (e.g., a coarse-beam-pointing gimbal) from the assembly, which may enhance the compactness and/or may decrease the assembly's weight.

One method of enabling the optical transceiver to compensate for the removal of the gimbal may be for the optical transceiver to include a support structure with multiple optical transmitters and multiple optical receivers pointing in various directions such that there is overlap between transmit beams and/or receive beams of the optical transmitters and/or optical receivers, respectively, in the far-field. In order to support transmissions with narrower beamwidths, each of the optical beam transmit paths may employ larger diameter optics (e.g., reflective or refractive types). Accordingly, as the diameter of the transmit path optics grows, less room on the surface of the support structure may be available for the optics of the optical receivers. This may lead to a smaller aperture diameter optics for each of the optical receivers. Accordingly, the magnitude of the transmit signal as collected by the receiver may decrease.

The methods and apparatuses described herein may enable increased beam collection efficiency while mitigating adverse effects associated with decreasing optical receivers' beam-condensing optics diameters. For instance, the optical transceiver may include a support structure with a surface and a set of optical transmitters perforating the surface of the support structure, where each optical transmitter of the set of optical transmitters is oriented in a different direction relative to each other within the set of optical transmitters. Additionally, the optical transceiver may include an optical receiver (e.g., a single optical receiver), where the optical receiver may include a luminescence wavelength-converting fiber and a detector. The luminescence wavelength-converting fiber may be disposed on the surface of the support structure and may be wrapped at least partially around the support structure. Additionally, at least one end of the luminescence wavelength-converting fiber (e.g., one or both ends of the luminescence wavelength-converting fiber) may be coupled with a detector (e.g., photodetector) with or without a beam concentrator. Wrapping the luminescence wavelength-converting fiber at least partially around the support structure may enable elimination of receive optics apertures (e.g., lenses). Accordingly, if the luminescence wavelength-converting fiber avoids first portions of the support structure associated with components of the optical transmitters and is wrapped around second portions of the support structure where one or more components of the optical transmitters are not present, the optical transceiver may be capable of receiving transmissions over the second portions of the support structure.

Features of the disclosure are initially described in the context of optical transceivers as described with reference to <FIG> and <FIG>. Features of the disclosure are described in the context of an optical communication system as described with reference to <FIG>. These and other features of the disclosure are further illustrated by and described with reference to an apparatus diagram and flowcharts that relate to gimballess quasi-omni optical communication transceivers as described with reference to <FIG>.

<FIG> illustrates an example of an optical transceiver <NUM> that supports gimballess quasi-omni optical communication transceivers in accordance with examples as disclosed herein. An optical transceiver <NUM> may include optical transmitters (e.g., optical transmitters <NUM>-a, <NUM>-b, <NUM>-c, <NUM>-d, and <NUM>-e) and optical receivers. The optical transmitters may be configured to transmit light at a wavelength and the optical receivers may be configured to receive light at the wavelength or a different wavelength. In some examples, the optical transmitters may transmit the light via one or more lasers and/or optical elements (e.g., lenses).

In some mobile laser communications (lasercom) applications (e.g., mobile underwater laser communications, mobile terrestrial laser communications, mobile aerial laser communications, mobile satellite laser communications), it may be advantageous to simplify laser beam pointing to a target, which may present challenges for optical wireless communications systems, as failure to accurately point laser beams may result in failure to receive the light or failure to retrieve the correct information from the light. Some optical laser assemblies may include a coarse-pointing gimbal. However, the coarse-pointing gimbal may include mechanical components that may experience delays between when the coarse-pointing gimbal points a laser in a first direction as compared to pointing the laser in a second direction and/or that may break down unexpectedly. Additionally, a more compact or more light-weight optical transceiver <NUM> (e.g., an optical laser transceiver) may be used as compared to stationary laser communications applications. In order to simplify laser beam pointing and/or to enhance compactness or decrease a weight of an optical transceiver assembly, the coarse-pointing gimbal (e.g., a two-axis gimbal) may be removed and the optical transceiver may be set up as an omni optical transmitter or a quasi-omni optical transmitter.

For instance, the optical transceiver <NUM> may include a support structure <NUM> with a set (e.g., ensemble) of optical transmitters oriented such that beams of the optical transmitters overlap in the far-field. If the beams of the set of optical transmitters overlap such that there is no gap at least in the far-field, the optical transceiver <NUM> may be referred to as an omni optical transceiver. Additionally or alternatively, if the beams of the set of optical transmitters overlap such that no gap larger than a threshold amount is present in at least the far-field, the optical transceiver <NUM> may be referred to as a quasi-omni optical transceiver. Optical transceivers <NUM> whose lasercom assemblies do not include gimbals may be referred to as gimballess optical transceivers. The optical transceiver <NUM> may include enough optical transmitters with a spatial arrangement such that transmit beams overlap in the far-field (e.g., such that the optical transceiver <NUM> is an omni or quasi-omni optical transceiver). A total number of optical transmitters and/or optical receiver may be reduced by scanning a field-of-regard using a two-axis mechanical fine-pointing mirror.

Free-space optical communications may be advantageous for communications systems that use beams with a beamwidth below a threshold amount (e.g., narrow beamwidth communications systems). For instance, to achieve a narrow beamwidth, a wavelength of lasers of the optical transmitters may be reduced and/or associated optics diameters may be increased for a given system (e.g., optical transceiver <NUM>) design. Such wavelengths may be, for instance, between <NUM> nanometers and <NUM> nanometers or greater than <NUM> nanometers. In some examples, the transmitter optics diameter may depend on a size of the support structure <NUM> (e.g., a size of the sphere) and a quantity of optical transmitters (e.g., transmit apertures) used. For instance, the diameter of the optics for each optical transmitter may be just large enough such that overlap (e.g., partial or complete overlap) between transmit beams is still present in the far-field. However, as the optics diameters of the optical transmitters increase, the optics diameters of the optical receivers may decrease by a corresponding amount. Accordingly, the optical transceiver may be less likely to receive transmissions from other devices performing laser communications with the optical transceiver.

One method of mitigating the reduced optics diameters of the optical receivers may be to have a separate support structure for the set of optical receivers. However, having the separate support structure may reduce a compactness or may increase a size, a weight, or an amount of materials used for the lasercom assembly. Accordingly, using the separate structure may decrease the ease with which such optical transceivers are moved between locations.

The present disclosure describes an optical transceiver <NUM> that may enable increased optics diameters for optical transceivers <NUM> while mitigating the amount by which optics diameters of optical receivers are decreased. Additionally, the described optical transceiver <NUM> may have beneficial properties related to a size, weight, or an amount of materials used for the optical transceiver <NUM> as compared to lasercom assemblies whose optical transceivers include a separate support structure for the optical transceiver. For instance, an optical transceiver <NUM> may include a support structure <NUM> with a surface and a set of optical transmitters perforating the surface of the support structure <NUM>, where each optical transmitter of the set of optical transmitters is oriented in a different direction relative to each other optical transmitter of the set of optical transmitters (e.g., optical transmitter <NUM>-a oriented in a first direction <NUM>-a and optical transmitter <NUM>-b oriented in a second direction <NUM>-b different than the first direction). Additionally, the optical transceiver <NUM> may include an optical receiver, where the optical receiver may include a luminescence wavelength-converting fiber <NUM> and a detector <NUM>. The luminescence wavelength-converting fiber <NUM> may be disposed on the surface of the support structure <NUM>, where the luminescence wavelength-converting fiber <NUM> is wrapped at least partially around the support structure <NUM> and is located between at least two pairs of the set of optical transmitters (e.g., optical transmitters <NUM>-b and <NUM>-d). Additionally, the luminescence wavelength-converting fiber <NUM> may be configured to absorb light at a first wavelength and emit light within a channel of the luminescence wavelength-converting fiber <NUM> at a second wavelength (e.g., a second wavelength different than the first wavelength). The detector <NUM> may be coupled with the luminescence wavelength-converting fiber <NUM> at least one end (e.g., one or both ends) of the luminescence wavelength-converting fiber <NUM>, where the detector <NUM> may be configured to convert the light at the second wavelength to an electrical signal. In some examples, the luminescence wavelength-converting fiber <NUM> may include or may be a single optical fiber. Additionally or alternatively, the luminescence wavelength-converting fiber <NUM> may include or be more than one optical fiber (e.g., where each end of each optical fiber is adjoined with at least one end of each other optical fiber such that the detector <NUM> is coupled with one or two ends, or where the detector <NUM> is coupled with one or more ends of each optical fiber).

In some examples, the optical transceiver <NUM> may include a set of lenses or a set of mirrors covering a perforated portion of the surface of the support structure <NUM>. In such examples, each lens of the set of lenses may be associated with a respective optical transmitter of the set of optical transmitters.

In some examples, the luminescence wavelength-converting fiber <NUM> may be wrapped at least once around the support structure <NUM>. Additionally, or alternatively, the luminescence wavelength-converting fiber <NUM> may be wrapped multiple times around the support structure <NUM>. In some examples, the luminescence wavelength-converting fiber <NUM> may be wrapped around the support structure <NUM> such that at least one quarter of a remaining portion (e.g., the portion not covered by the set of optical transmitters <NUM>) of the surface of the support structure is covered by the luminescence wavelength-converting fiber <NUM>. In some examples, the luminescence wavelength-converting fiber <NUM> may be wrapped around the support structure <NUM> such that each optical transmitter and/or lenses associated with each optical transmitter are not covered. Additionally or alternatively, the luminescence wavelength-converting fiber <NUM> may be wrapped around the support structure <NUM> such that a portion (e.g., at or above <NUM>%, at or above <NUM>%, at or above <NUM>%, at or above <NUM>%,) of the surface that is not perforated by any optical transmitters and/or covered by lenses covering the optical transmitters is covered by the luminescence wavelength-converting fiber <NUM>.

In some examples, the support structure <NUM> may be formed in the shape of a sphere, a spheroid (e.g., an ellipsoid), or a polyhedron (e.g., dodecahedron, octahedron, icosahedron, uniform polyhedrons, isohedrons). In other examples, the support structure <NUM> may be formed in a shape of at least a quarter of a sphere (e.g., a half-sphere), at least a quarter of an ellipsoid (e.g., a half-ellipsoid), or at least quarter of a polyhedron (e.g., a half-polyhedron). In some examples, each optical transmitter may be configured to emit light at the first wavelength.

In some examples, the first wavelength may have a value outside of a visible spectrum of light. Having the value outside the visible spectrum of light may decrease a likelihood that laser communications are detected for secure applications (e.g., applications in which detection of laser communications by an intercepting recipient may have an adverse effect).

In some examples, the optical transceiver <NUM> may perform laser communications. For instance, the optical transceiver <NUM> may absorb, at the luminescence wavelength-converting fiber <NUM> of the optical receiver, light at the first wavelength. The optical transceiver <NUM> may emit light within the channel of the luminescence wavelength-converting fiber <NUM> at a second wavelength based on absorbing the light at the first wavelength and may convert, using a detector <NUM> of the optical receiver, the light at the second wavelength to an electrical signal ,where the detector <NUM> is coupled with at least one end of the luminescence wavelength-converting fiber <NUM>.

In some examples, the luminescence wavelength-converting fiber <NUM> be a fiberoptics cable and may operate according to red-shifted luminescence. Additionally or alternatively, the luminescence wavelength-converting fiber <NUM> may be an optical waveguide (e.g., a glass fiber-optic cable, a glass slab doped with fluorescent dyes, a plasmonic nano-antenna phased-array). In some examples, incident light (e.g., laser light from a communication system) may be absorbed and re-emitted at a different wavelength (e.g., absorbed and re-emitted by dye molecules of the luminescence wavelength-converting fiber <NUM>). The waveguide may collect a portion of the emitted light and may propagate it to the end (e.g., the end coupled with the detector <NUM>) with re-absorption (e.g., due to red-shifted luminescence).

The methods and apparatuses described herein may eliminate receive optics apertures (e.g., lenses), which may allow for an increased transmit optics aperture diameters to be employed on a single support structure <NUM> as compared to lasercom assemblies that use receive optics apertures. Accordingly, beam collimation and link efficiency may increase (e.g., link margin may improve). Additionally, the optical transceiver <NUM> may be nondirectional, which may reduce the etendue of the system such that larger active area photodetectors may be used.

Although luminescence wavelength-converting fiber <NUM> is illustrated as being wrapped around support structure <NUM> in a single direction (e.g., horizontally in the plane of X direction <NUM> and Z direction <NUM>) in <FIG>, luminescence wavelength-converting fiber <NUM> may be wrapped around support structure <NUM> in multiple directions (e.g., may be wrapped vertically in the plane of Y direction <NUM> and Z direction <NUM> as well as horizontally as shown in the orientation of <FIG>) to increase coverage of support structure <NUM> between optical transmitters <NUM>. In some cases, one or more wraps of luminescence wavelength-converting fiber <NUM> (e.g., in a first direction) may cross other wraps of luminescence wavelength-converting fiber <NUM> (e.g., in a second direction). Further, luminescence wavelength-converting fiber <NUM> may be wrapped in more than two directions (e.g., a first direction, a second direction orthogonal to the first direction, a third direction that crosses both the first direction and the second direction), which may allow for additional coverage of support structure <NUM> between optical transmitters <NUM>.

<FIG> illustrates an example of an optical transceiver <NUM> that supports gimballess quasi-omni optical communication transceivers in accordance with examples as disclosed herein. In some examples, one or more aspects of optical transceiver <NUM> may be an example of one or more aspects of optical transceiver <NUM> as described herein. For instance, support structures <NUM>-a or <NUM>-b may each be examples of one or more aspects of the support structure <NUM> as described with reference to <FIG>; optical transmitter <NUM>-f and <NUM>-g may be examples of one or more aspects of optical transmitters <NUM> as described with reference to <FIG>; luminescence wavelength-converting fiber <NUM>-a may be an example of one or more aspects of a luminescence wavelength-converting fiber <NUM> as described with reference to <FIG>; detector <NUM>-a may be an example of one or more aspects of a detector <NUM> as described with reference to <FIG>; directions <NUM>-c and <NUM>-d may be examples of one or more aspects of directions <NUM>-a or <NUM>-b as described with reference to <FIG>.

In some examples the luminescence wavelength-converting fiber <NUM>-a and optical transmitters <NUM>-d and <NUM>-e may be on separate assemblies or separate support structures (e.g., optical transceiver <NUM> may have separate transmitter and receiver configurations). For instance, luminescence wavelength-converting fiber <NUM>-a may be wrapped around support structure <NUM>-b and the set of optical transmitters may perforate the surface of support structure <NUM>-a. The separate support structures may be coupled together (e.g., via a coupling component <NUM>, which may be a rod).

Having the luminescence wavelength-converting fiber <NUM>-a and optical transmitters <NUM>-f and <NUM>-g on separate assemblies may enable multiple links in different directions to be maintained simultaneously. In some examples, the luminescence wavelength-converting fiber <NUM>-a may be wrapped around at least a portion of support structure <NUM>-b (e.g., at or above <NUM>%, at or above <NUM>%, at or above <NUM>%, at or above <NUM>%, at or above <NUM>%) and the optical transmitters <NUM>-f and <NUM>-g may perforate the surface of support structure <NUM>-a. In some examples, support structure <NUM>-b having the luminescence wavelength-converting fiber <NUM>-a may have one or more advantages as compared to the support structure <NUM>-b having receive optics apertures (e.g., lenses). For instance, the luminescence wavelength-converting fiber <NUM>-a may be capable of covering a higher portion of the first support structure than the receive optics apertures. Additionally, in examples in which the luminescence wavelength-converting fiber <NUM>-a consists of a single fiber-optic cable (e.g., as compared to multiple fiber-optic cables with adjoined ends), an electrical signal produced by the detector <NUM>-a may have less noise (e.g., a higher signal-to-noise ratio).

<FIG> illustrates an example of an optical communication scheme <NUM> that supports gimballess quasi-omni optical communication transceivers in accordance with examples as disclosed herein. In some examples, optical communication scheme <NUM> may implement one or more aspects of optical transceivers <NUM> and/or <NUM>. For instance, optical transmitter <NUM>-h may be an example of one or more of optical transmitters <NUM> as described with reference to <FIG> and/or <NUM>; luminescence wavelength-converting fiber <NUM>-b may be an example of a luminescence wavelength-converting fiber <NUM> as described with reference to <FIG> and/or <NUM> and detector <NUM>-b may be an example of a detector <NUM> as described with reference to <FIG> and/or <NUM>.

In some examples, optical transmitter <NUM>-h may be covered by a lens <NUM>. Additionally, both ends of luminescence wavelength-converting fiber <NUM>-b may be coupled with detector <NUM>-b. In some examples, luminescence wavelength-converting fiber <NUM>-b and detector <NUM>-b may be included within an optical receiver <NUM>. In one example, optical transmitter <NUM>-h may transmit light <NUM> (e.g., via a laser) corresponding to information to be communicated at a first wavelength. Optical receiver <NUM> may receive the light <NUM> using luminescence wavelength-converting fiber <NUM>-b. For instance, luminescence wavelength-converting fiber <NUM>-b may include a layer <NUM> which may receive the light <NUM> at the first wavelength and may be doped with fluorescent dye that may absorb the light <NUM> at the first wavelength and emit light <NUM> at a second wavelength (e.g., a red-shifted wavelength). Additionally or alternatively, layer <NUM> may be a plasmonic nano-antenna phased-array. The light <NUM> emitted by the layer <NUM> of luminescence wavelength-converting fiber <NUM>-b may propagate within a channel <NUM> to detector <NUM>-b, where detector <NUM>-b may convert the light to an electrical signal corresponding to the information to be communicated. In some examples, a mirror may be used in conjunction with or in place of the lens <NUM> for some or each of the set of lenses in order to transmit the light.

<FIG> shows a block diagram <NUM> of an optical transceiver <NUM> that supports gimballess quasi-omni optical communication transceivers in accordance with examples as disclosed herein. The optical transceiver <NUM> may be an example of aspects of an optical transceiver as described with reference to <FIG>. The optical transceiver <NUM>, or various components thereof, may be an example of means for performing various aspects of gimballess quasi-omni optical communication transceivers as described herein. For example, the optical transceiver <NUM> may include a luminescence wavelength-converting fiber <NUM>, a detector <NUM>, an optical transmitter <NUM>, or any combination thereof. Each of these components may communicate, directly or indirectly, with one another.

The luminescence wavelength-converting fiber <NUM> may be configured as or otherwise support a means for absorbing, at a luminescence wavelength-converting fiber of an optical receiver, light at a first wavelength, where the luminescence wavelength-converting fiber is disposed on a surface of a support structure such that the luminescence wavelength-converting fiber is wrapped at least partially around the support structure and located between at least two pairs of a set of optical transmitters, where the set of optical transmitters perforates the surface of the support structure, and where each optical transmitter of the set of optical transmitters is oriented in a different direction relative to each other optical transmitter of the set of optical transmitters. In some examples, the luminescence wavelength-converting fiber <NUM> may be configured as or otherwise support a means for emitting light within a channel of the luminescence wavelength-converting fiber at a second wavelength based at least in part on absorbing the light at the first wavelength. The detector <NUM> may be configured as or otherwise support a means for converting, using a detector of the optical receiver, the light at the second wavelength to an electrical signal, where the detector is coupled with at least one end of the luminescence wavelength-converting fiber.

In some examples, each optical transmitter of the set of optical transmitters is associated with one or more respective concentrating optical elements (e.g., a lens or a set of lenses). In some examples, the set of optical elements covers a perforated portion of the surface of the support structure.

In some examples, the luminescence wavelength-converting fiber is wrapped multiple times around the support structure.

In some examples, the luminescence wavelength-converting fiber is wrapped around the support structure such that a perforated portion of the surface of the support structure associated with the set of optical transmitters is not covered by the luminescence wavelength-converting fiber and at least one quarter of a remaining portion of the surface of the support structure is covered by the luminescence wavelength-converting fiber.

In some examples, the support structure is formed in a shape of a sphere, a spheroid, or a polyhedron.

In some examples, the support structure is formed in a shape of at least a quarter of a sphere, at least a quarter of an ellipsoid, or at least a quarter of a polyhedron.

In some examples, the detector is coupled with each end of the luminescence wavelength-converting fiber.

In some examples, the luminescence wavelength-converting fiber includes a single optical fiber.

In some examples, the luminescence wavelength-converting fiber includes more than one optical fiber.

In some examples, the optical transmitter <NUM> may be configured as or otherwise support a means for emitting, from an optical transmitter of the set of optical transmitters, light at the first wavelength.

In some examples, the first wavelength has a value outside of a visible spectrum of light.

<FIG> shows a flowchart illustrating a method <NUM> that supports gimballess quasi-omni optical communication transceivers in accordance with examples as disclosed herein. The operations of method <NUM> may be implemented by an optical transceiver or its components as described herein. For example, the operations of method <NUM> may be performed by an optical transceiver as described with reference to <FIG>. In some examples, an optical transceiver may execute a set of instructions to control the functional elements of the device to perform the described functions. Additionally, or alternatively, the optical transceiver may perform aspects of the described functions using special-purpose hardware.

At <NUM>, the method may include absorbing, at a luminescence wavelength-converting fiber of an optical receiver, light at a first wavelength, where the luminescence wavelength-converting fiber is disposed on a surface of a support structure such that the luminescence wavelength-converting fiber is wrapped at least partially around the support structure and located between at least two pairs of a set of optical transmitters, where the set of optical transmitters perforates the surface of the support structure, and where each optical transmitter of the set of optical transmitters is oriented in a different direction relative to each other optical transmitter of the set of optical transmitters. The operations of <NUM> may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of <NUM> may be performed by a luminescence wavelength-converting fiber <NUM> as described with reference to <FIG>.

At <NUM>, the method may include emitting light within a channel of the luminescence wavelength-converting fiber at a second wavelength based at least in part on absorbing the light at the first wavelength. The operations of <NUM> may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of <NUM> may be performed by a luminescence wavelength-converting fiber <NUM> as described with reference to <FIG>.

At <NUM>, the method may include converting, using a detector of the optical receiver, the light at the second wavelength to an electrical signal, where the detector is coupled with at least one end of the luminescence wavelength-converting fiber. The operations of <NUM> may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of <NUM> may be performed by a detector <NUM> as described with reference to <FIG>.

In some examples, an apparatus as described herein may perform a method or methods, such as the method <NUM>. The apparatus may include features, circuitry, logic, means, or instructions (e.g., a non-transitory computer-readable medium storing instructions executable by a processor), or any combination thereof for performing the following aspects of the present disclosure:.

Some drawings may illustrate signals as a single signal; however, the signal may represent a bus of signals, where the bus may have a variety of bit widths.

" The detailed description includes specific details to provide an understanding of the described techniques. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

As used herein, including in the claims, "or" as used in a list of items (for example, a list of items prefaced by a phrase such as "at least one of" or "one or more of') indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). For example, an exemplary step that is described as "based on condition A" may be based on both a condition A and a condition B without departing from the scope of the appended claims.

Claim 1:
A system, comprising:
a support structure (<NUM>) having a surface;
a set of optical transmitters (<NUM>) perforating the surface of the support structure (<NUM>), wherein each optical transmitter (<NUM>) of the set of optical transmitters (<NUM>) is oriented in a different direction (<NUM>-a, <NUM>-b) relative to each other optical transmitter (<NUM>) of the set of optical transmitters (<NUM>); and
an optical receiver (<NUM>) comprising:
a luminescence wavelength-converting fiber (<NUM>) disposed on the surface of the support structure (<NUM>), wherein the luminescence wavelength-converting fiber (<NUM>) is wrapped at least partially around the support structure (<NUM>) and located between at least two pairs of the set of optical transmitters (<NUM>), and wherein the luminescence wavelength-converting fiber (<NUM>) is configured to absorb light (<NUM>) at a first wavelength and emit light (<NUM>) within a channel (<NUM>) of the luminescence wavelength-converting fiber (<NUM>) at a second wavelength; and
a detector (<NUM>) coupled with at least one end of the luminescence wavelength-converting fiber (<NUM>), wherein the detector (<NUM>) is configured to convert the light (<NUM>) at the second wavelength to an electrical signal.