Patent Description:
This section introduces aspects that may help facilitate a better understanding of the disclosure.

An optical transceiver may include one or more of the following optical devices: (i) an electrically driven light source, such as a laser diode; (ii) an optical amplifier; (iii) an optical-to-electrical converter, such as a photodiode; and (iv) an optoelectronic component that can control propagation and/or certain properties of light, such as an optical modulator or an optical switch. The optical transceiver may additionally include one or more electronic components that enable the use of these and possibly other optical devices in a manner consistent with the intended function or application. Different integration and packaging technologies may be used to combine various optical devices and the corresponding electronic components into a functional, practically useful integrated circuit, package, card, and/or assembly. Such technologies continue to expand and evolve, e.g., through the development of new solutions for the emerging products and applications.

<CIT> discloses methods and arrangements for duplex fiber handling. <CIT> discloses 3D photonic integration with light coupling elements.

Disclosed herein are various embodiments of optical transmitters, receivers, and transceivers implemented using a plurality of surface-coupled optical devices that are manufactured on the same planar substrate and then post-processed to provide some of the devices with different respective partially transparent front mirrors compatible with and/or customized for different respective optical functions. When appropriately electrically biased and driven, different subsets of such devices can operate as lasers, optical modulators, optical amplifiers, and photodetectors, respectively. In this manner, an integrated array of such devices can be customized to provide the optical functions needed for the intended end product. For example, an optical transmitter can be constructed using an integrated array that comprises three surface-coupled optical devices configured to operate as a laser, an optical modulator, and an optical amplifier, respectively. An optical receiver can be constructed using an integrated array that comprises two surface-coupled optical devices configured to operate as an optical amplifier and a photodetector, respectively.

Advantageously, the use of integrated arrays of such surface-coupled optical devices can help to streamline the system design, simplify the system integration/packaging, and/or reduce the system development and production costs.

According to the invention, provided is an apparatus as defined by claim <NUM>.

Other aspects, features, and benefits of various disclosed embodiments will become more fully apparent, by way of example, from the following detailed description and the accompanying drawings, in which:.

<FIG> shows a schematic cross-sectional side view of a surface-coupled optical device (SCOD) <NUM> according to an embodiment. Depending on the electrical configuration, SCOD <NUM> can be operated as a vertical-cavity surface-emitting laser (VCSEL), a semiconductor optical amplifier (SOA), an electro-absorption modulator (EAM), or a photodetector (PD). The different electrical configurations corresponding to these four different optical functions of SCOD <NUM> are described in more detail below.

In the invention, the same physical instance of SCOD <NUM> is reconfigurable by changing the electrical configuration thereof, to provide any selected one of the four above-mentioned optical functions or any selected one of a subset of the four optical functions. In such embodiments, the optical function of that particular SCOD <NUM> can be changed, by changing the electrical configuration thereof, such as the bias voltage and/or the bias-voltage polarity applied thereto.

In the invention, SCOD <NUM> is designed to perform a selected one of the four optical functions, e.g., by having certain physical characteristics that are beneficial for and/or geared towards that particular optical function. In some of such embodiments, that particular SCOD <NUM> may not be able to perform at least some of the other three optical functions even if placed into a corresponding electrical configuration.

SCOD <NUM> is "surface-coupled" in the sense that, in operation, this device receives and/or emits a light beam in a direction that is substantially orthogonal to the main plane of the device, which is parallel to the XY-coordinate plane of the XYZ triad shown in <FIG>. The XY-coordinate plane typically corresponds to the main plane of the planar substrate on which the layered structure of SCOD <NUM> has been formed during fabrication (see, e.g., <FIG>). Due to this geometry, a large number of SCODs <NUM> can be manufactured on a single substrate (e.g., a semiconductor wafer).

SCOD <NUM> includes a plurality of layers that are substantially parallel to the XY-coordinate plane. The direction orthogonal to those layers (i.e., parallel to the Z-coordinate axis) may hereafter be referred to as the vertical or surface-normal direction. The directions parallel to those layers may hereafter be referred to as the horizontal or lateral directions. Some of the layers may include two or more sub-layers (not explicitly shown in <FIG>) that differ from each other in chemical composition and/or the concentration and type of the introduced dopant(s). SCOD <NUM> also includes metal electrodes <NUM> and <NUM><NUM>-<NUM><NUM> electrically connected to some of the layers as described in more detail below. In an example embodiment, the vertical size (or thickness) of SCOD <NUM> is significantly smaller than its lateral size (e.g., depth and/or width).

In some embodiments, metal electrodes <NUM><NUM>-<NUM><NUM> can be electrically connected to one another by being parts of the same electrode having, e.g., an O-shape in the top view thereof (e.g., if viewed along the Z-coordinate axis).

SCOD <NUM> comprises an optical resonator defined by mirrors <NUM> and <NUM>.

In an example embodiment, mirror <NUM> is a metal (e.g., gold or gold-plated) mirror having relatively high (e.g., ><NUM>%) reflectivity at the nominal operating wavelength at the side of the mirror facing down (in the projection shown in <FIG>). Mirror <NUM> is typically such that it does not allow any light to pass therethrough. As a result, the shown embodiment of SCOD <NUM> can typically be used only in an optical configuration that does not require light to be transmitted through the SCOD, e.g., in reflection.

In some alternative embodiments, mirror <NUM> can be replaced by a suitable distributed Bragg reflector (DBR) mirror. As known in the pertinent art, a DBR mirror can be formed, e.g., using a stack of semiconductor or dielectric layers, each having a quarter-wavelength thickness, with adjacent layers of the stack having alternating refractive indices. In such embodiments, SCOD <NUM> may be used in transmission.

In an example embodiment, mirror <NUM> is a partially transparent dielectric mirror that enables light of the nominal operating wavelength to be properly coupled into and/or out of the optical resonator. For illustration purposes and without any implied limitations, <FIG> shows an embodiment in which mirror <NUM> comprises four dielectric layers <NUM><NUM>-<NUM><NUM>. In an alternative embodiment, mirror <NUM> can be implemented using a different (from four) number of constituent dielectric layers.

In some embodiments, layers <NUM><NUM> and <NUM><NUM> comprise silicon dioxide, and layers <NUM><NUM> and <NUM><NUM> comprise silicon nitride. In an alternative embodiment, mirror <NUM> can be implemented using dielectric layers of other suitable chemical composition.

In some embodiments, mirror <NUM> can be replaced by a suitable DBR mirror made of semiconductor materials.

The optical resonator defined by mirrors <NUM> and <NUM> includes p-type semiconductor layers <NUM> and <NUM>, n-type semiconductor layers <NUM> and <NUM>, and a multiple-quantum-well (MQW) structure <NUM> sandwiched therebetween. MQW structure <NUM> comprises a stack of alternating relatively thin layers <NUM> and <NUM> made of different respective semiconductor materials. In an example embodiment, the semiconductor materials of layers <NUM> and <NUM> are intrinsic semiconductors. Layer <NUM> may have a higher dopant concentration than layer <NUM>, such that layers <NUM> and <NUM> can be referred to as p+ and p layers, respectively. Layer <NUM> may similarly have a higher dopant concentration than layer <NUM>, such that layers <NUM> and <NUM> can be referred to as n+ and n layers, respectively.

In the invention, MQW structure <NUM> comprises quantum dots (not explicitly shown in <FIG>), each quantum dot being respective quantum well. In some embodiments, quantum dots may be used in addition to or instead of the layer-type quantum wells shown in <FIG>.

In the embodiment shown in <FIG>, the optical resonator defined by mirrors <NUM> and <NUM> also includes an optional dielectric layer <NUM> located between mirror <NUM> and semiconductor layer <NUM>. In an example embodiment, this layer comprises SiO<NUM> or Si<NUM>N<NUM>. In an alternative embodiment, layer <NUM> can be absent.

A person of ordinary skill in the art will understand that the choices of (i) the semiconductor materials for layers <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> and (ii) the vertical distance between mirrors <NUM> and <NUM> may depend on the intended operating wavelength of SCOD <NUM>. For example, different telecommunications applications may use different embodiments of SCOD <NUM> designed for the spectral bands located near <NUM>, <NUM>, and <NUM>, respectively.

In some embodiments, SCOD <NUM> may include additional layers (not explicitly shown in <FIG>) located between layers <NUM> and <NUM><NUM>. An example of such layers can be one or more etch-stop layers and one or more buffer layers used in the manufacturing process, e.g., as explained below in reference to <FIG>.

In an example embodiment, the following semiconductor materials can be used to implement SCOD <NUM>: (i) Zn-doped In(x)Ga(<NUM>-x-y)Al(y)As for layer <NUM>; (ii) Zn-doped In(x)Al(<NUM>-x)As for layer <NUM>; (iii) In(x)Ga(<NUM>-x)As for layers <NUM>; (iv) In(x)Al(<NUM>-x)As for layers <NUM>; (v) Si-doped In(x)Al(<NUM>-x)As for layer <NUM>; and (vi) Si-doped In(x)Ga(<NUM>-x-y)Al(y)As for layer <NUM>. In alternative embodiments, other semiconductor materials and dopants can also be used.

In the invention, layers <NUM> and <NUM> and MQW structure <NUM> form a p-i-n diode (also sometimes referred to as a "PIN diode") that is electrically biased using electrodes <NUM> and <NUM>. Ohmic contact between electrode <NUM> and layer <NUM> can be created using metal contact pads <NUM> and layer <NUM> as known in the art. Ohmic contact between electrode(s) <NUM> and layer <NUM> can be created using metal contact pads <NUM> and an additional thin n+ or n++ semiconductor layer (not explicitly shown in <FIG>) located between contact pads <NUM> and layer <NUM>.

To operate SCOD <NUM> as a VCSEL, electrodes <NUM> and <NUM> can be electrically connected to apply an appropriate forward bias to PIN diode <NUM>/<NUM>/<NUM>.

As used herein, the term "forward bias" refers to an electrical configuration of a semiconductor-junction diode in which the n-type material is at a low potential, and the p-type material is at a high potential. If the forward bias is greater than the intrinsic voltage drop Vpn across the corresponding p-i-n junction, then the corresponding potential barrier can be overcome by the electrical carriers, and a relatively large forward current can flow through the junction. For example, for silicon-based diodes the value of Vpn is approximately <NUM> V. For germanium-based diodes, the value of Vpn is approximately <NUM> V, etc..

When PIN diode <NUM>/<NUM>/<NUM> is appropriately forward-biased, a relatively large injection current flows through MQW structure <NUM>, thereby causing the MQW structure to generate light that is then amplified due to the multiple passes therethrough caused by light oscillation in the optical resonator between mirrors <NUM> and <NUM>. The light generated in this manner can escape from the optical resonator of SCOD <NUM> through mirror <NUM>, thereby generating an output light beam. A person of ordinary skill in the art will understand that to enable the VCSEL function, SCOD <NUM> needs to be capable of a relatively high optical gain, which can be achieved, in part, by properly selecting the materials and structure of mirror <NUM>.

To operate SCOD <NUM> as an SOA, electrodes <NUM> and <NUM> can be electrically connected to apply an appropriate forward bias to PIN diode <NUM>/<NUM>/<NUM>, which forward bias may be different from that used in the above-described VCSEL configuration. More specifically, in the SOA configuration, the gain provided by the optical resonator of SCOD <NUM> is typically below the lasing threshold, but is nevertheless sufficient for generating new light, through stimulated emission, in response to an external light beam coupled into the optical resonator through mirror <NUM>. The corresponding value of the optical gain can be achieved, in part, by properly selecting the materials and structure of mirror <NUM>. In some embodiments, the materials and structure of mirror <NUM> selected to provide a desired SOA function of SCOD <NUM> may be different from those used to provide the above-described VCSEL function.

To operate SCOD <NUM> as an EAM, electrodes <NUM> and <NUM> can be electrically connected to apply to PIN diode <NUM>/<NUM>/<NUM> a combination of an appropriate reverse bias and a driving radio-frequency (RF) signal.

As used herein, the term "reverse bias" refers to an electrical configuration of a semiconductor-junction diode in which the n-type material is at a high electrical potential, and the p-type material is at a low electrical potential. The reverse bias typically causes the depletion layer to grow wider due to a lack of electrons and/or holes, which presents a high impedance path across the junction and substantially prevents a current flow therethrough. However, a very small reverse leakage current can still flow through the junction in the reverse-bias configuration.

The principle of operation of SCOD <NUM> in the EAM configuration is based on the so-called quantum-confined Stark effect (QCSE) due to which the optical absorption near the effective band edge of MQW structure <NUM> depends on the applied electric field. More specifically, the reverse bias applied to the PIN diode <NUM>/<NUM>/<NUM> causes MQW structure <NUM> to be subjected to an electric field of certain strength. During the positive swing of the driving RF signal, the electric-field strength increases, thereby red-shifting the band edge. During the negative swing of the driving RF signal, the electric-field strength decreases, thereby blue-shifting the band edge. These band-edge shifts change the light transmittance of MQW structure <NUM> at the carrier wavelength, thereby modulating the intensity of light that oscillates in the optical resonator between mirrors <NUM> and <NUM> and escapes from the optical resonator through mirror <NUM>.

A person of ordinary skill in the art will understand that an optimized EAM function of SCOD <NUM> may be facilitated, at least in part, by a corresponding (e.g., different from any of the above-described) selection of the materials and structure of mirror <NUM>.

To operate SCOD <NUM> as a PD, electrodes <NUM> and <NUM> can be electrically connected to apply to PIN diode <NUM>/<NUM>/<NUM> an appropriate dc reverse bias, which may be different from (e.g., larger than) that used in the above-described EAM configuration. The reverse bias creates a relatively large electric field across the p-i-n junction that can separate the electrical carriers (e.g., holes and electrons) generated therein by the absorbed light coupled into the optical resonator of SCOD <NUM> through mirror <NUM>. The separated electrical carriers generate a photocurrent that can be collected and measured as known in the art to determine the light intensity.

A person of ordinary skill in the art will understand that an optimized PD function of SCOD <NUM> may be facilitated, at least in part, by a corresponding (e.g., different from any of the above-described) selection of the materials and structure of mirror <NUM>.

The lateral dimensions of the optical resonator in SCOD <NUM> can be defined using an external aperture (not explicitly shown in <FIG>) and/or ion-implanted regions <NUM>. Ion-implanted regions <NUM> can be formed by implanting suitable ions (e.g., the hydrogen ions, H+) into MQW structure <NUM> around its periphery, e.g., as indicated in <FIG>. The ion-implantation process disrupts, perturbs, and/or destroys the semiconductor lattice in regions <NUM>, thereby inhibiting the flow of electrical current(s) therethrough and/or hindering the physical processes therein that are pertinent to the above-described optical functions of SCOD <NUM>. In an example embodiment, the middle portion of MQW structure <NUM> laterally bounded by regions <NUM> may have an approximately circular cross-sectional shape in a plane parallel to the XY-coordinate plane. In alternative embodiments, other cross-sectional geometric shapes are also possible.

Encapsulating and/or filler materials can be used as known in the pertinent art to cover and/or fill the gaps (if any) between the various layers, structures, and electrodes of SCOD <NUM>, thereby providing a substantially monolithic and mechanically robust overall device structure.

One beneficial optical characteristic of SCOD <NUM> is that its operation, in various above-described configurations, can be substantially polarization-independent due to the surface-coupled nature of the device. For comparison, waveguide-based semiconductor optical devices (e.g., lasers, amplifiers, modulators, and photodetectors) can typically be polarization-dependent, e.g., due to a relatively large difference in the group indices (i.e., effective refractive indices) of the transverse electric (TE) and transverse magnetic (TM) polarizations in the corresponding optical waveguides. This particular characteristic can make it relatively difficult to construct a polarization-diverse waveguide-based semiconductor optical device having a substantially polarization-independent response and/or capable of appropriately handling polarization-division-multiplexed (PDM) signals. Advantageously, the latter problem can be significantly alleviated or avoided altogether with the use of various embodiments of SCOD <NUM>.

<FIG> pictorially illustrate a manufacturing method that can be used to make an array <NUM> of SCODs <NUM> according to an embodiment.

<FIG> shows a schematic cross-sectional side view of array <NUM>. For illustration purposes and without any implied limitations, <FIG> shows an embodiment in which array <NUM> comprises four SCODs <NUM>, which are labeled <NUM><NUM>-<NUM><NUM>. In an alternative embodiment, array <NUM> may have a different (from four) number of SCODs <NUM>.

SCODs <NUM><NUM>-<NUM><NUM> are supported on and electrically and mechanically connected to a device carrier <NUM> using solder bumps <NUM> attached to electrodes <NUM>, <NUM> (also see <FIG>). The orientation of SCODs <NUM><NUM>-<NUM><NUM> is such that mirrors <NUM> are facing away from a surface <NUM> of device carrier <NUM>, on which the SCODs are mounted. Electrical connections between each of SCODs <NUM><NUM>-<NUM><NUM> and the corresponding external electrical circuit(s) (such as, circuit <NUM>, <FIG>) can be provided by patterned conducting (such as metal) layers located within the body and/or on surface <NUM> of device carrier <NUM>. In various embodiments, device carrier <NUM> can be implemented using any one or any suitable combination of the following: one or more substrates, one or more redistribution layers (RDLs), one or more interposers, one or more laminate plates, and one or more circuit sub-mounts, etc..

In some embodiments, SCODs <NUM><NUM>-<NUM><NUM> can be nominally identical.

In some other embodiments, SCODs <NUM><NUM>-<NUM><NUM> may have nominally identical portions <NUM> (also see <FIG>), but different respective mirrors <NUM><NUM>-<NUM><NUM>. In such embodiments, some of mirrors <NUM><NUM>-<NUM><NUM> may differ from some of the other mirrors, e.g., in reflectivity/transmissivity, thickness, the number of constituent layers <NUM> (see <FIG>), and/or the chemical composition of at least some of those constituent layers.

In some embodiments, different subsets of SCODs <NUM><NUM>-<NUM><NUM> may be specifically designed and configured to perform different respective optical functions selected from the above-described VCSEL, SOA, EAM, and PD functions. In different ones of such embodiments, the number of such subsets can be two, three, or four.

Array <NUM> of <FIG> can be fabricated by first forming a corresponding array <NUM> of portions <NUM> on a suitable substrate <NUM> as illustrated in <FIG>. In an example embodiment, substrate <NUM> can be an InP substrate. Portions <NUM> can be formed on substrate <NUM> in a conventional manner, e.g., using a multistep fabrication process comprising at least some of the following: photolithography, ion implantation, dry and/or wet etching, thermal treatments and anneals, oxidation, chemical and physical vapor deposition, epitaxial growth, electrochemical deposition, and chemical-mechanical planarization.

In the next fabrication step, array <NUM> is flip-chip bonded to device carrier <NUM> using solder bumps <NUM>. After the flip-chip bonding, substrate <NUM> is removed, e.g., by reactive etching, thereby exposing layers <NUM> of portions <NUM> (e.g., as indicated in <FIG>) or the corresponding etch-stop layers (not explicitly shown in <FIG>). Mirrors <NUM><NUM>-<NUM><NUM> are then formed on the exposed top surfaces of the resulting circuit <NUM> (<FIG>), thereby converting the latter into array <NUM> (<FIG>).

<FIG> shows a block diagram of an optical assembly <NUM> according to an embodiment. Optical assembly <NUM> comprises a SCOD <NUM> mounted on device carrier <NUM>, e.g., as described above in reference to <FIG>. Optical assembly <NUM> further comprises an optical circulator <NUM> configured to couple light in and/or out of SCOD <NUM>.

Optical circulator <NUM> has three optical ports, which are labeled in <FIG> using reference numerals <NUM>, <NUM>, and <NUM>, respectively. Port <NUM> is configured to direct an optical input beam <NUM> received from an external light source to port <NUM>. Port <NUM> is configured to direct light of beam <NUM> toward mirror <NUM> of SCOD <NUM>. Port <NUM> is further configured to receive an optical output beam <NUM> emitted by SCOD <NUM> through mirror <NUM> and direct it to port <NUM>. Port <NUM> is configured to direct light of optical beam <NUM> to external circuits.

In some embodiments, a lens (not explicitly shown in <FIG>) may be placed between port <NUM> of optical circulator <NUM> and mirror <NUM> of SCOD <NUM> to improve the optical coupling efficiency and/or reduce optical losses.

In some embodiments, port <NUM> may comprise a collimator configured to collimate the light thereat.

In some embodiments, optical circulator <NUM> can be implemented using the fiber-optic circulator Model <NUM>-<NUM>-APC commercially available from Thorlabs, Inc.

In some embodiments, an array of optical circulators <NUM> may be used to couple light in and out of array <NUM> (<FIG>). In such an array, not all of the ports of optical circulators <NUM> may be used. For example, an optical circulator <NUM> optically coupled to a SCOD <NUM> configured to operate as a VCSEL may use only ports <NUM> and <NUM> to couple the light of output optical beam <NUM> out of the that SCOD. As another example, an optical circulator <NUM> optically coupled to a SCOD <NUM> configured to operate as a PD may use only ports <NUM> and <NUM> to couple the light of input optical beam <NUM> into that SCOD.

<FIG> shows a block diagram of an optical assembly <NUM> according to another embodiment. Optical assembly <NUM> comprises a SCOD <NUM> mounted on device carrier <NUM>, e.g., as described above in reference to <FIG>. Optical assembly <NUM> further comprises a planar lightwave circuit (PLC) <NUM> configured to couple light in and/or out of SCOD <NUM>. The main plane of planar lightwave circuit <NUM> is parallel to the YZ-coordinate plane.

Circuit <NUM> comprises optical waveguides <NUM> and <NUM> connected to an edge <NUM> of that circuit as indicated in <FIG>. More specifically, the end portions of waveguides <NUM> and <NUM> are oriented with respect to edge <NUM> at an angle that is slightly (e.g., within ±<NUM> degrees) different from <NUM> degrees. The ends of waveguides <NUM> and <NUM> are separated from one another by a relatively small distance d selected such that both ends are in the field of view of a coupling lens <NUM> located between edge <NUM> of circuit <NUM> and mirror <NUM> of SCOD <NUM>.

In some alternative embodiments, lens <NUM> can be replaced by a suitable set of two or more different lenses configured for optimal light-coupling efficiency for the intended application of circuit <NUM>.

In some other alternative embodiments, lens <NUM> can be removed, and edge <NUM> can be positioned to be in very close proximity to (e.g., in direct contact with) mirror <NUM>.

In the shown embodiment, waveguide <NUM> is configured to direct, through lens <NUM>, an optical input beam <NUM> received from an external light source toward mirror <NUM>. Waveguide <NUM> is configured to receive, through lens <NUM>, an optical output beam <NUM> emitted by SCOD <NUM> through mirror <NUM> and direct it to external circuits. Lens <NUM> is configured to appropriately shape and redirect optical beams <NUM> and <NUM> to provide a relatively high optical-coupling efficiency between circuit <NUM> and SCOD <NUM>.

In some embodiments, circuit <NUM> may be used to couple light in and out of array <NUM> (<FIG>). In such embodiments, circuit <NUM> may have multiple pairs of optical waveguides <NUM> and <NUM> (not explicitly shown in <FIG>; see <FIG>) connected to edge <NUM>. Some of such pairs may be configured to use only one of the two respective waveguides. For example, optical waveguides <NUM> and <NUM> optically coupled to a SCOD <NUM> configured to operate as a VCSEL may use only waveguide <NUM> to couple the light of output optical beam <NUM> out of the that SCOD. As another example, optical waveguides <NUM> and <NUM> optically coupled to a SCOD <NUM> configured to operate as a PD may use only waveguide <NUM> to couple the light of input optical beam <NUM> into that SCOD.

Additional embodiments of circuit <NUM> may be constructed and operated using waveguide circuits and optical arrangements disclosed, e.g., in <CIT>.

<FIG> shows a block diagram of an optical transceiver <NUM> according to an embodiment. Transceiver <NUM> comprises: (i) an optical transmitter <NUM>; (ii) an optical receiver <NUM>; and (iii) an embodiment of SCOD array <NUM> (also see <FIG>) that includes SCODs <NUM><NUM>-<NUM><NUM>. SCODs <NUM><NUM>-<NUM><NUM> are used to implement optical transmitter <NUM>. SCODs <NUM><NUM> and <NUM><NUM> are used to implement optical receiver <NUM>.

Transceiver <NUM> further comprises an embodiment of planar lightwave circuit <NUM> (also see <FIG>), an array <NUM> of lenses <NUM><NUM>-<NUM><NUM> (also see <FIG>), and an electrical circuit <NUM> operatively connected to SCOD array <NUM> as indicated in <FIG>.

Waveguide circuit <NUM> includes fiber connectors <NUM> and <NUM> to which external optical fibers can be connected. Connector <NUM> is configured to operate as an optical output port of transceiver <NUM>. Connector <NUM> is configured to operate as an optical input port of transceiver <NUM>.

Electrical circuit <NUM> is connected to SCOD array <NUM> using an electrical bus <NUM>. In operation, circuit <NUM> can perform some or all of the following: (i) provide respective bias voltages to SCODs <NUM><NUM>-<NUM><NUM>; (ii) generate electrical RF drive signals to be applied to some of the SCODs (e.g., SCOD <NUM><NUM>) in response to an electrical analog data-input signal <NUM>; and (iii) generate an electrical analog data-output signal <NUM> in response to the corresponding RF signal(s) received from some of the SCODs (e.g., SCOD <NUM><NUM>).

In the shown embodiment, SCODs <NUM><NUM>-<NUM><NUM> are configured to operate as a VCSEL, an EAM, a SOA, a PD, and a SOA, respectively. These configurations can be obtained, e.g., as described above in reference to <FIG> and <FIG>.

Optical transmitter <NUM> can operate, for example, as follows.

SCOD <NUM><NUM> generates an optical output beam <NUM><NUM>, which is then coupled, by way of lens <NUM><NUM>, into waveguide <NUM><NUM> of circuit <NUM>. Waveguide <NUM><NUM> directs the received light to waveguide <NUM><NUM>, which outputs it as an optical output beam <NUM><NUM>. Lens <NUM><NUM> couples beam <NUM><NUM> into SCOD <NUM><NUM>, where it is modulated to generate a corresponding modulated optical output beam <NUM><NUM>. The modulation is performed using the electrical RF drive signal generated by circuit <NUM> in response to the data-input signal <NUM>, with the drive signal being applied to SCOD <NUM><NUM> by way of electrical bus <NUM>. Lens <NUM><NUM> couples beam <NUM><NUM> into waveguide <NUM><NUM> of circuit <NUM>. Waveguide <NUM><NUM> directs the received light to waveguide <NUM><NUM>, which outputs it as an optical output beam <NUM><NUM>. Lens <NUM><NUM> couples beam <NUM><NUM> into SCOD <NUM><NUM>, where it is amplified to generate a corresponding amplified optical output beam <NUM><NUM>. Lens <NUM><NUM> then couples beam <NUM><NUM> into waveguide <NUM><NUM> of circuit <NUM>. Finally, waveguide <NUM><NUM> directs the received light to connector <NUM>, where it can be coupled into the optical fiber connected thereto for transmission to a remote receiver (not explicitly shown in <FIG>).

Optical receiver <NUM> can operate, for example, as follows.

Waveguide <NUM><NUM> of circuit <NUM> receives, by way of connector <NUM> and the optical fiber connected thereto, an optical input signal received from a remote transmitter (not explicitly shown in <FIG>). Waveguide <NUM><NUM> then outputs the received light as an optical output beam <NUM><NUM>. Lens <NUM><NUM> couples beam <NUM><NUM> into SCOD <NUM><NUM>, where it is amplified to generate a corresponding amplified optical output beam <NUM><NUM>. Lens <NUM><NUM> then couples beam <NUM><NUM> into waveguide <NUM><NUM> of circuit <NUM>. Waveguide <NUM><NUM> directs the received light to waveguide <NUM><NUM>, which outputs it as an optical output beam <NUM><NUM>. Lens <NUM><NUM> couples beam <NUM><NUM> into SCOD <NUM><NUM>, where it is converted into a corresponding electrical signal. This electrical signal is then directed by way of electrical bus <NUM> to circuit <NUM>, where it is used to generate the data-output signal <NUM>.

Various additional embodiments can be obtained, e.g., using one or more of the following modifications of transceiver <NUM>.

SCOD <NUM><NUM> can be removed, and waveguide <NUM><NUM> can be connected to an external laser (not explicitly shown in <FIG>).

SCOD <NUM><NUM> can be removed, and waveguide <NUM><NUM> can be connected to fiber connector <NUM> instead of waveguide <NUM><NUM>.

A stand-alone optical receiver can be obtained by removing, disabling, or disconnecting transmitter <NUM>.

A stand-alone optical transmitter can be obtained by removing, disabling, or disconnecting receiver <NUM>.

In some embodiments, the embodiment of circuit <NUM> shown in <FIG> can be replaced by a functionally similar optical circuit constructed using a plurality of appropriately connected optical circulators <NUM>.

While this disclosure includes references to illustrative embodiments, this specification is not intended to be construed in a limiting sense. Various modifications of the described embodiments, as well as other embodiments within the scope of the disclosure, which are apparent to persons skilled in the art to which the disclosure pertains are deemed to lie within the principle and scope of the disclosure.

It will be further understood that various changes in the details, materials, and arrangements of the parts which have been described and illustrated in order to explain the nature of this disclosure may be made by those skilled in the art without departing from the scope of the disclosure.

The use of figure numbers and/or figure reference labels (if any) in the claims is intended to identify one or more possible embodiments of the claimed subject matter in order to facilitate the interpretation of the claims.

Unless otherwise specified herein, the use of the ordinal adjectives "first," "second," "third," etc., to refer to an object of a plurality of like objects merely indicates that different instances of such like objects are being referred to, and is not intended to imply that the like objects so referred-to have to be in a corresponding order or sequence, either temporally, spatially, in ranking, or in any other manner.

Throughout the detailed description, the drawings, which are not to scale, are illustrative only and are used in order to explain, rather than limit the disclosure. The use of terms such as height, length, width, top, bottom, is strictly to facilitate the description of the embodiments and is not intended to limit the embodiments to a specific orientation. For example, height does not imply only a vertical rise limitation, but is used to identify one of the three dimensions of a three dimensional structure as shown in the figures. Such "height" would be vertical where the layers are horizontal but would be horizontal where the layers are vertical, and so on. Similarly, while all figures show the different layers as horizontal layers such orientation is for descriptive purpose only and not to be construed as a limitation.

Also for purposes of this description, the terms "couple," "coupling," "coupled," "connect," "connecting," or "connected" refer to any manner known in the art or later developed in which energy is allowed to be transferred between two or more elements, and the interposition of one or more additional elements is contemplated, although not required. Conversely, the terms "directly coupled," "directly connected," etc., imply the absence of such additional elements.

The described embodiments are to be considered in all respects as only illustrative and not restrictive. In particular, the scope of the invention is indicated by the appended claims rather than by the description and figures herein.

It will thus be appreciated that those of ordinary skill in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the disclosure. Furthermore, all examples recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the disclosure and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions.

As used in this application, the term "circuitry" may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry); (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and/or digital hardware circuit(s) with software/firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions); and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation. " This definition of circuitry applies to all uses of this term in this application, including in any claims.

Claim 1:
An apparatus (<NUM>), comprising a plurality of optical devices (<NUM><NUM>, <NUM><NUM>, <NUM><NUM>, <NUM><NUM>, <NUM><NUM>) supported on a planar surface, each of the optical devices (<NUM><NUM>, <NUM><NUM>, <NUM><NUM>, <NUM><NUM>, <NUM><NUM>) being configured to receive light, emit light, or receive and emit light substantially orthogonally to the planar surface;
wherein the plurality of optical devices (<NUM><NUM>, <NUM><NUM>, <NUM><NUM>, <NUM><NUM>, <NUM><NUM>) include a first optical device and a second optical device;
wherein the first optical device is configured to operate as an optical device of a first type;
wherein the second optical device is configured to operate as an optical device of a second type different from the first type;
wherein the first type and the second type are selected from a device-type set consisting of a vertical-cavity surface-emitting laser, a semiconductor optical amplifier, a reflective optical modulator, and a photodetector, wherein each of the optical devices comprises a respective semiconductor diode that includes respective multiple quantum wells; and wherein the apparatus further comprises an electrical circuit connected to electrically bias the respective semiconductor diodes to change the operation of the optical device to a type from the device-type set.