Optical interposer for optical transceivers

Abstract

An optical interposer for providing optimal optical coupling between an optical transceiver interface and an external optical interface includes an interposer photonic integrated circuit (PIC) operably configured to couple optical signals between the optical transceiver interface and the external optical interface, one or more waveguide-based optical devices operably integrated on a common substrate, and one or more interposer input / output (I / O) channels operably configured with the optical transceiver interface and the external optical interface.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of photonic integrated systems for optical transceivers or optical sensor integrated systems, and more particularly, to the integration of photonic integrated systems for providing multiple functions in a photonic integrated circuit using CMOS manufacturing technology. Background Art

[0002] The rapid growth of cloud computing and artificial intelligence applications is driving Internet technology giants to build powerful data centers. So far, building large data centers has been more cost-effective and less complicated than building a large number of medium-sized data centers to expand processing capacity. However, in order to transmit large amounts of data at ultra-high speeds between server nodes / racks in a data center, high transmission bandwidth is required. Traditionally, interconnection is achieved by sending and receiving data in the form of electrical signals using copper cables and electrical transceivers. Such electrical solutions are very large and have a transmission distance of less than 20 meters (m) at a data rate of 10 gigabits per second (Gbps).

[0003] An optical interposer is a photonic integrated circuit (PIC) that includes one or more waveguide-based optical devices integrated on a common substrate (usually a semiconductor substrate). The interposer PIC is used to couple optical signals between an optical transceiver interface (e.g., a PIC waveguide) and an external optical interface (e.g., an optical fiber, an optical fiber array, a planar lightwave circuit (PLC), or a free-space optical system).

[0004] Fiber-optic networks have replaced copper-based networks for many years, given the obvious advantages of optical solutions in having a smaller footprint and longer transmission distances (up to 300m at 50Gbps). Conventional optical transceivers in data centers are mostly multimode fiber (MMF). A typical multimode fiber link has a data rate of 10 megabits per second (Mbps) to 10Gbps over a link length of only 600m. However, it is not uncommon for node interconnections in today's giant data centers to easily exceed a distance of 500m to 2km. Therefore, there is a strong demand for single-mode transceivers for single-mode optical transmission to connect optical fibers between nodes. Conventional single-mode transceivers consist of many high-cost discrete optical components. They have a large footprint and require a high-cost assembly process and maintenance.

[0005] With the advent of silicon photonics (SiPh) technology, the possibility of low-cost and small footprint solutions for large-scale interconnection over 500m to 2km has increased. SiPh technology uses state-of-the-art complementary metal oxide semiconductor (CMOS) foundry processes to manufacture photonic integrated circuit (PIC) devices, in which most optical components are integrated on a single silicon chip. However, the optical mode size (the spot size of light in the waveguide) of the input / output (I / O) port of the SiPh chip (also called Si PIC) is about 1μm, while that of the single-mode fiber (SMF) is about 10μm. Such a large difference in optical mode size introduces large optical power loss in butt coupling (head-to-head coupling between SiPIC I / O port and SMF). The optical power loss of conventional coupling methods from PIC to optical fiber, PLC (planar lightwave circuit) and edge-emitting laser diodes is very high (more than 50%).

[0006] The main reason is that the optical mode size of the waveguide in the PIC is much smaller than that of optical fiber, PLC and laser diode. Traditional coupling methods use discrete free-space optical components (such as micro lenses) to convert the optical mode size. This high-cost method is not a viable solution to this problem. Unless this coupling problem is solved, SiPh technology will not be a solution for large-scale implementation of SMF interconnects.

[0007] Therefore, the present invention aims to provide an optical interposer for optimal optical coupling of an optical transceiver interface and an external optical interface to overcome the above-mentioned disadvantages of the prior art. Summary of the invention

[0008] The aforementioned objects of the present invention are achieved by adopting an optical interposer for coupling optical signals between an optical transceiver interface and an external optical interface. In particular, the optical interposer comprises: an interposer photonic integrated circuit (PIC) operably configured / adapted to couple optical signals between the optical transceiver interface and the external optical interface; one or more waveguide-based optical devices operably integrated on a common substrate; and one or more interposer input / output (I / O) channels operably configured / adapted to transceiver PIC input / output (I / O) channels of the optical transceiver interface and the external optical interface.

[0009] According to an embodiment of the invention, the optical transceiver interface is a transceiver photonic integrated circuit (PIC).

[0010] According to an embodiment of the present invention, the common substrate is a semiconductor substrate.

[0011] According to an embodiment of the present invention, the external optical interface is any one of an optical fiber, an optical fiber array, a planar lightwave circuit (PLC), a free space optical system, and the like.

[0012] According to an embodiment of the present invention, an optical interposer is located between a transceiver photonic integrated circuit (PIC) and an external optical interface.

[0013] According to an embodiment of the present invention, an optical interposer is operable to function as a semiconductor chip.

[0014] According to an embodiment of the present invention, an optical interposer is operable to function as an optical mode size converter between a transceiver PIC input / output (I / O) channel and an external optical interface.

[0015] According to an embodiment of the present invention, the optical interposer is operable to function as a polarization selector and / or a polarization switch.

[0016] According to an embodiment of the present invention, the optical interposer is operable to function as a polarization rotator.

[0017] According to an embodiment of the present invention, an optical interposer is operable to function as a routing circuit to distribute the pitch.

[0018] According to an embodiment of the present invention, the optical interposer is operable to function as a polarization beam splitter.

[0019] According to an embodiment of the present invention, the optical interposer is operable to function as an optical multiplexer (MUX) and / or an optical demultiplexer (deMUX).

[0020] According to an embodiment of the present invention, an optical multiplexer (MUX) is operably configured / adapted to receive one or more optical signals from a transceiver photonic integrated circuit (PIC) and multiplex the one or more optical signals into a single signal.

[0021] According to an embodiment of the present invention, an optical demultiplexer (deMUX) receives a single signal from an external optical interface and demultiplexes the single signal into one or more signals.

[0022] According to an embodiment of the present invention, the optical interposer further includes an angled interposer interface.

[0023] According to an embodiment of the present invention, the optical interposer further comprises an angled interposer waveguide.

[0024] According to an embodiment of the invention, the refractive index value of the interposer waveguide is between the transceiver photonic integrated circuit waveguide value and the external optical interface waveguide value.

[0025] According to an embodiment of the present invention, an optical interposer is connected to one or more external optical interfaces.

[0026] According to embodiments of the present invention, an optical interposer is operably configured / adapted to provide optimal optical coupling (and / or optical connection) with one or more transceiver PIC input / output channels and one or more external optical channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Therefore, in order to understand in detail the manner in which the above-mentioned features of the present invention are understood, a more specific description of the present invention briefly summarized above may be given by reference to embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings only illustrate typical embodiments of the present invention and are therefore not to be considered as limiting the scope of the present invention, as the present invention may admit to other equally effective embodiments.

[0028] Figure 1A is a schematic diagram showing a top view of an optical interposer according to an embodiment of the present invention;

[0029] Figure 1B is a schematic diagram showing a side view of an optical interposer according to an embodiment of the present invention;

[0030] Figure 2 is a schematic diagram showing an optical interposer having an external optical interface according to one embodiment of the present invention;

[0031] Figure 3 is a schematic diagram showing an optical interposer having an external optical interface according to another embodiment of the present invention;

[0032] Figure 4 is a schematic diagram showing an optical interposer having an external optical interface according to yet another embodiment of the present invention;

[0033] Figure 5 is a schematic diagram of an optical interposer showing transverse electric (TE) polarization and transverse magnetic (TM) polarization according to one embodiment of the present invention;

[0034] Figure 6 is a schematic diagram showing an optical interposer for transverse electric (TE) polarization according to another embodiment of the present invention;

[0035] Figure 7 is a schematic diagram of an optical interposer showing transverse magnetic (TM) polarization according to yet another embodiment of the present invention;

[0036] Figure 8 is a schematic diagram of an interposer photonic integrated circuit (PIC) showing optical signal coupling between a plurality of transceiver PIC input / output (I / O) channels and a plurality of external channels in accordance with an embodiment of the present invention;

[0037] Fig. 9is a schematic diagram showing an optical inserter for multiplexing and / or demultiplexing optical signals according to an embodiment of the present invention;

[0038] Fig.10 A schematic diagram showing an optical interposer connected to a plurality of external optical interfaces according to an embodiment of the present invention is shown;

[0039] Fig.11 An interposer interface of an optical interposer to a transceiver photonic integrated circuit (PIC) according to one embodiment of the present invention is shown;

[0040] Fig.12 illustrates an angled interposer interface of an optical interposer to an external optical interface according to another embodiment of the present invention;

[0041] Fig.13 shows an angled waveguide on an optical interposer interface to a transceiver photonic integrated circuit (PIC) according to one embodiment of the present invention;

[0042] Fig.14 An angled waveguide at an optical interposer interface to an external optical interface is shown according to another embodiment of the present invention.

[0043] Components List

[0044] Optical Interposer-100

[0045] Interposer Photonic Integrated Circuit (Pic)-105

[0046] Optical Transceiver Interface-110

[0047] Transceiver Photonic Circuits - 115

[0048] External Optical Interface-120

[0049] Inserter Waveguide-125

[0050] Interposer Input / Output (I / O) Channels for Optical Transceiver Interface - 130

[0051] Interposer Input / Output (I / O) Channels for External Optical Interface - 135

[0052] Transceiver PIC Input / Output (I / O) Channels - 140

[0053] Transceiver Waveguide-145

[0054] Fiber-150

[0055] Fiber Array-155

[0056] Planar Lightwave Circuit (PLC)-160

[0057] Free Space Optical System-165

[0058] External PLC circuit-170

[0059] External light path-175

[0060] For convenience and better understanding of the exemplary examples in various embodiments of the present invention, the following reference numerals may be used interchangeably:

[0061] Transceiver Photonic Integrated Circuit (PIC)-110 DETAILED DESCRIPTION

[0062] The present invention relates to an optical interposer operably configured / adapted to provide an optimal optical coupling (and / or optical connection) between an optical transceiver interface and an external optical interface.

[0063] By reference Figures 1A to 14 The principles and advantages of the present invention can be best understood.In the following detailed description of illustrative or exemplary embodiments of the present disclosure, specific embodiments in which the present disclosure may be practiced are described in sufficient detail to enable those skilled in the art to practice the disclosed embodiments.

[0064] Therefore, the following detailed description should not be construed as limiting, and the scope of the present disclosure is defined by the appended claims and their equivalents. References in the specification to "one embodiment," "embodiments," "multiple embodiments," or "one or more embodiments" are intended to indicate that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present disclosure.

[0065] Figure 1A and Figure 1B Schematic top and side views of an optical interposer according to one or more embodiments of the present invention are shown. In particular, the optical interposer 100 includes an interposer photonic integrated circuit (PIC) 105, one or more waveguide-based optical devices having an interposer waveguide 125, and one or more interposer input / output (I / O) channels (130 and / or 135).

[0066] The interposer photonic integrated circuit (PIC) 105 is operably configured / adapted to couple optical signals between the optical transceiver interface 110 and the external optical interface 120 .

[0067] The waveguide-based optical device with the interposer waveguide 125 is integrated on a common substrate. In particular, the common substrate is a semiconductor substrate.

[0068] The interposer input / output (I / O) channel 130 is operably configured / adapted with the transceiver PIC input / output (I / O) channel 140 of the optical transceiver interface 110. Also, the interposer input / output (I / O) channel 135 is also operably configured / adapted with the external optical interface 120.

[0069] According to an embodiment of the present invention, optical transceiver interface 110 is a transceiver photonic integrated circuit (PIC) 110. Transceiver photonic integrated circuit (PIC) 110 also includes transceiver photonic circuits 115, transceiver waveguides 145, and transceiver PIC input / output (I / O) channels 140.

[0070] According to an embodiment of the present invention, the external optical interface 120 is any one of an optical fiber 150, an optical fiber array 155, a planar lightwave circuit (PLC) 160, a free space optical system 165, and the like.

[0071] Reference Figure 1A and Figure 1B , the optical interposer 100 includes a transceiver photonic integrated circuit (PIC) 110 and an optical fiber array 155 in an external optical interface 120 .

[0072] According to an embodiment of the present invention, an optical interposer 100 is operably positioned between a transceiver photonic integrated circuit (PIC) 110 and an external optical interface 120 to provide optimal optical coupling between the transceiver photonic integrated circuit (PIC) 110 and the external optical interface 120 .

[0073] According to an embodiment of the present invention, the optical interposer 100 is operable to function as a semiconductor chip to provide a bridge between a transceiver photonic integrated circuit (PIC) 110 and an external optical interface 120. In particular, the bridge provides a specific connection to the external optical interface 120 with different functions. In addition, the optical interposer 100 functions as a semiconductor chip that is independent of a functional photonic integrated circuit (PIC) assembled as an extension of the transceiver photonic integrated circuit (PIC) 110.

[0074] According to an embodiment of the present invention, the optical interposer 100 is operable to function as an optical mode size converter for optimal optical coupling (or optical connection) with a transceiver photonic integrated circuit (PIC) 110. In particular, Figure 1AAs shown, the optical interposer 100 acts as an optical mode size converter between the transceiver PIC input / output (I / O) channel 140 and an external optical interface 120 such as an optical fiber 150. In addition, the waveguide-based optical devices respectively have edges for optimal optical coupling (or optical connection) with the transceiver photonic integrated circuit (PIC) 110, and adjust the optical mode morphology in the waveguide-based optical device to output a suitable optical mode to couple into the external optical interface, usually with a larger optical mode size.

[0075] Figure 2 , Figure 3 as well as Figure 4 Schematic diagram of an optical interposer connected to an external optical interface according to one or more embodiments of the present invention is shown. Figure 2 , Figure 3 as well as Figure 4 In the figure, the external optical interfaces are optical fiber 150, planar lightwave circuit (PLC) 160 and free space optical system 165.

[0076] According to an embodiment of the present invention, Figure 1A , Figure 2 , Figure 3 as well as Figure 4 As shown, the optical interposer 100 is operable to match the pitch configuration of transceiver photonic integrated circuit (PIC) input / output (I / O) channels 140 and external optical interfaces 120 to reduce the size of waveguide-based optical devices and simplify multi-channel devices.

[0077] Figure 5 1 is a schematic diagram of an optical inserter showing transverse electric (TE) polarization and transverse magnetic (TM) polarization according to an embodiment of the present invention. In particular, the optical inserter 100 selects input optical signals based on TE polarization / TM polarization, and outputs TE mode optical signals and TM mode optical signals to different output ports. The fiber array 155 has a pair of optical I / Os, referred to as Tx / Rx. The optical inserter 100 provides a bridge connecting the transceiver photonic integrated circuit (PIC) 110 and the fiber array 155 for transmitting the Tx signal from the transceiver photonic integrated circuit (PIC) 110 to the fiber array 155. In addition, in order to receive a signal from the fiber array 155 array, light is combined with TE and TM modes.

[0078] According to an embodiment of the present invention, the optical interposer 100 is operable to function as a polarization beam splitter. Specifically, the optical interposer selects the TE and TM modes and directs them to different ports and couples them back to the receiver side of the transceiver photonic integrated circuit (PIC) 110.

[0079] In the context of PIC / PLC, TE polarization refers to an optical mode whose electric field is substantially parallel to the plane and perpendicular to the direction of propagation. And, TM polarization refers to an optical mode whose electric field is substantially perpendicular to the plane and the direction of propagation.

[0080] Figure 6 1 is a schematic diagram of an optical interposer showing transverse electric (TE) polarization according to another embodiment of the present invention. In particular, the waveguide-based optical device on the interposer photonic integrated circuit (PIC) 105 is operably configured / adapted to select the input optical signal based on TE / TM polarization, and also switch the input TM mode optical signal to a TE mode optical signal. Although the TE and TM modes are selectively directed to two different ports, during propagation in the optical interposer 100, the TM mode is rotated to the TE mode. Therefore, the output port contains the TE optical signal.

[0081] Figure 7 1 is a schematic diagram of an optical interposer showing transverse magnetic (TM) polarization according to yet another embodiment of the present invention. The waveguide-based optical device on the interposer photonic integrated circuit (PIC) 105 is operably configured / adapted to select an input optical signal based on TE / TM polarization, and also switch the input TE mode optical signal to a TM mode optical signal. Although the TE and TM modes are selectively directed to two different ports, during propagation in the optical interposer 100, the TE mode is rotated to the TM mode. Therefore, the output port contains the TM optical signal.

[0082] According to an embodiment of the present invention, the optical interposer 100 is operable to function as a polarization selector.

[0083] According to an embodiment of the present invention, the optical interposer 100 is operable to function as a polarization switch.

[0084] According to an embodiment of the present invention, the optical interposer 100 is operable to function as a polarization rotator.

[0085] According to an embodiment of the present invention, an optical interposer is operable to function as a routing circuit to distribute the pitch.

[0086] Figure 8 1 is a schematic diagram of an interposer photonic integrated circuit (PIC) showing coupling of optical signals according to an embodiment of the present invention. In particular, the waveguide-based optical devices on the optical interposer 100 are operably configured / adapted to couple optical signals between multiple transceiver PIC input / output (I / O) channels and multiple external channels. In addition, the multi-channel coupling provides a routing path for the photonic integrated circuit so that the output channels have a designable pitch to couple to an external optical interface.

[0087] Fig. 9is a schematic diagram showing an optical inserter for multiplexing and / or demultiplexing optical signals according to an embodiment of the present invention.

[0088] According to an embodiment of the present invention, at the transmitter side, the optical interposer 100 receives multiple optical signals from a transceiver photonic integrated circuit (PIC) 110 , multiplexes the multiple optical signals into a single signal and outputs the single signal to an external optical interface 120 .

[0089] According to an embodiment of the present invention, the optical interposer receives a single signal from the external optical interface 120, demultiplexes it into several signals, and directs them to the transceiver photonic integrated circuit (PIC) 110. Thus, the number of input / output (I / O) channels in the external optical interface 120 is reduced.

[0090] According to embodiments of the present invention, the optical interposer 100 is operable to function as an optical multiplexer (MUX) and / or an optical demultiplexer (deMUX) to allow for fabrication of passive components with lower phase errors, lower internal propagation losses and higher manufacturing tolerances and lower thermal sensitivity.

[0091] Fig.10 A schematic diagram of an optical interposer according to an embodiment of the present invention is shown, the optical interposer further comprising a plurality of external optical interfaces. In particular, the plurality of external optical interfaces are not limited to one edge of the optical interposer.

[0092] According to an embodiment of the present invention, multiple channels are used as one of the above functions, such as but not limited to optical mode size converter, splitter / combiner, wavelength filter, polarization beam splitter, polarization rotator and optical multiplexer / demultiplexer.

[0093] Fig.11 and Fig.12 An interposer interface of an optical interposer relative to a transceiver photonic integrated circuit (PIC) 110 and an external optical interface 120 according to one or more embodiments of the present invention is shown. In particular, the interposer interface is an angled interposer interface. In addition, the angled interposer interface is laterally polished at an angle to minimize back reflections.

[0094] Fig.13 and Fig.14 An interposer interface to a transceiver photonic integrated circuit (PIC) 110 and an external optical interface 120 is shown in accordance with one or more embodiments of the present invention. In particular, the interposer interface is not intentionally angled, the waveguides are adjustably tilted at a specific angle to achieve a non-angled interface and achieve the same effect of minimizing back reflections.

[0095] According to an embodiment of the present invention, the refractive index value of the interposer waveguide is between the transceiver photonic integrated circuit waveguide value and the external optical interface waveguide value (or optical path in free space).

[0096] Therefore, embodiments of the present invention provide an optical interposer for optimally coupling optical signals (and / or optical connections) between an optical transceiver interface and an external optical interface. In particular, the optical interposer has higher alignment tolerance, lower waveguide propagation loss, higher performance, lower internal propagation loss, and higher manufacturing tolerance.

[0097] Although the present invention has been described with reference to specific embodiments, it is obvious to those skilled in the art that the present invention is not limited to the details of the aforementioned illustrative embodiments, and that various changes and modifications may be made to the present invention without departing from the scope of the present invention. Therefore, the present embodiments should be considered illustrative in all respects, rather than restrictive, and the scope of the present invention is indicated by the appended claims rather than the foregoing description, and therefore, all changes falling within the meaning and scope of the equivalents of the claims are intended to be included therein. In other words, it is expected that any and all modifications, variations or equivalents that are covered within the scope of the basic principles and that this patent application claims protection of its basic properties are covered. It should be understood that the terms used in this manner are interchangeable where appropriate, and that embodiments of the present invention can be operated in accordance with the present invention in other orders or in orientations different from those described above or shown.

Claims

1. An optical interposer for providing optimal optical coupling between an optical transceiver interface and an external optical interface, the optical interposer being operable as a semiconductor chip and comprising: an interposer photonic integrated circuit (PIC) operably configured to couple optical signals between the optical transceiver interface and the external optical interface; one or more waveguide-based optical devices operably integrated on a common substrate of the semiconductor chip; as well as A plurality of interposer input / output (I / O) channels are disposed on an edge of the semiconductor chip and are operably coupled to transceiver PIC input / output (I / O) channels (140) of the optical transceiver interface (110) and the external optical interface.

2. The optical interposer according to claim 1, wherein: The optical transceiver interface is a transceiver photonic integrated circuit (PIC).

3. The optical interposer according to claim 1, wherein: The common substrate of the semiconductor chips is a semiconductor substrate.

4. The optical interposer according to claim 1, wherein: The external optical interface is any one of an optical fiber, an optical fiber array, a planar lightwave circuit (PLC), and a free space optical system.

5. The optical interposer according to claim 2, wherein: The optical interposer is located between the transceiver photonic integrated circuit (PIC) and the external optical interface.

6. The optical interposer according to claim 1, wherein: The optical interposer is operable to serve as an optical mode size converter between the transceiver PIC input / output (I / O) channels and the external optical interface.

7. The optical interposer according to claim 1, wherein: The optical interposer is operable to function as a polarization selector and / or a polarization switch.

8. The optical interposer according to claim 1, wherein: The optical interposer is operable to function as a polarization rotator.

9. The optical interposer according to claim 1, wherein: The optical interposer is operable to function as a routing optical circuit to distribute the pitch.

10. The optical interposer according to claim 1, wherein: The optical interposer is operable to function as a polarization beam splitter.

11. The optical interposer of claim 1, wherein: The optical interposer is operable to function as an optical multiplexer (MUX) and / or an optical demultiplexer (deMUX).

12. The optical interposer of claim 11, wherein: The optical multiplexer (MUX) is operably configured to receive a plurality of optical signals from a transceiver photonic integrated circuit (PIC) and multiplex the plurality of optical signals into a single signal.

13. The optical interposer of claim 11, wherein: The optical demultiplexer (deMUX) receives a single signal from the external optical interface and demultiplexes the single signal into a plurality of signals.

14. The optical interposer of claim 1, wherein: The optical interposer also includes an angled interposer interface.

15. The optical interposer of claim 1, wherein: The one or more waveguide-based optical devices also include an angled interposer waveguide.

16. The optical interposer of claim 1, wherein: A first refractive index value of an interposer waveguide in the one or more waveguide-based optical devices is between a second refractive index value of a waveguide in a transceiver photonic integrated circuit serving as the optical transceiver interface and a third refractive index value of a waveguide in the external optical interface.

17. The optical interposer of claim 1, wherein: The optical interposer also includes a plurality of external optical interfaces.

18. The optical interposer of claim 1, wherein: The optical interposer is operably configured to provide optimal optical coupling with a plurality of transceiver PIC input / output (I / O) channels and a plurality of external optical channels.

Images