The cost-effective and repeatable technology for integration of polymer multimode waveguide and out-of-plane 45° reflector mirrors is developed. This method is cost-effective, repeatable, robust, and fully compatible with the standard manufacturing processes for a 90° optical bending structure.
The basic concept of the technology for integration of waveguide and out-of-plane 45° reflector mirrors is as follows; 1) The positively patterned master in order to mold waveguides is manufactured by using photolithography and Deep RIE (Reactive Ion Etching). And the master is polished to obtain 45°-inclined plane. 2) Both sides of the positively patterned master are divided into three parts by using a sawing machine. One is a center master (main-master) with a positively patterned waveguide and the others are side masters (sub-master) without a pattered waveguide. The main master and sub-master turned over get back together again. 3) The negatively patterned PDMS master to be able to mold simultaneously both waveguide and out-of-plane 45° reflector mirrors is manufactured through pouring PDMS gel into master and thermally curing the PDMS master. 4) The multimode tapered waveguides with out-of-plane 45° reflector mirrors are simultaneously embossed by using PDMS master. The UV (Ultraviolet) curable material is organic-inorganic hybrid material (HYBRIMER, core index: 1.51, clad index: 1.48).
The transmitter module is constructed on a MOB. The MOB was employed for several purposes; to align optical module passively, to use as heat sinker and also to support the boards. On this MOB, 1×4 arrays of vertical-cavity surface-emitting laser (VCSEL) and Tapered Waveguide with 45° reflector mirrors are integrated. The height and width of waveguide's core are 100 μm, 60 μm respectively and the pitch is 250 μm. The transmission access lines in transmitter are designed considering differential impedance matching for high-speed operation. We measured the insertion loss of this transmitter module using a 62.5 μm graded index fiber. The average insertion loss value is roughly about 7dB.
The system performance of data- and telecommunication equipment must keep up with the increasing network speed. Optical interconnections technology is a promising alternative for high-throughput systems. We demonstrate the optical backplane system using a waveguide-embedded optical backplane and two processing boards. The transmitter and receiver modules were prepared for optical printed circuit boards (PCBs), which consists of the metal optical bench, the driver chips, vertical-cavity surface-emitting lasers (VCSELs), photodiodes, and a tapered polymeric waveguide. We report high-speed transmission of 27–1 pseudorandom bit sequence (PRBS) nonreturn to zero (NRZ) data up to 10 Gbits/s through the optical backplane system. The results demonstrate that the optical backplane system can be practical and valuable for the future high-throughput systems by using metal optical bench and precisely machined optical plug-adaptor structure to achieve stable board-to-board interconnection.
The performance of data and telecommunication equipment must keep up with the increasing network speed. Optical interconnection technology is a promising alternative for high throughput systems. The Optical backplane system was demonstrated with waveguide-embedded optical backplane, transmitter board and receiver board. The transmitter and receiver module were prepared for optical PCB, which consists of the metal optical bench, the driver chips, VCSELs, photodiodes and a tapered polymeric waveguide. And parallel optical transmitter and a receiver module were attached onto the processing boards for the interconnection with optical backplane board. The tapered polymeric waveguides are fabricated using the hot embossing technique. And the propagation loss of the waveguide was approximately 0.1dB/cm at 850nm. The waveguide-embedded optical backplane boards were fabricated by using conventional PCB lamination process. The data transmission characteristics of the processing board have been investigated. In our optical backplane system, we demonstrated up to 10Gb/s 2<sup>7</sup>-1 PRBS NRZ data transmission from the transmitter board to the receiver board through optical backplane. The BERs were less than 10<sup>-12</sup> under 8Gb/s data rate, which is sufficient level for telecommunications.
A fully optical PCB with transmitter/receiver system boards and optical bakcplane was prepared, which is board-to-board interconnection by an optical slot. We report a 10 Gb/s PRBS NRZ data transmission between transmitter system board and optical backplane embedded multimode polymeric waveguide arrays. The basic concept of the optical PCB is as follows; 1) Metal optical bench is integrated with optoelectronic devices, driver and receiver circuits, polymeric waveguide and access line PCB module. 2) Multimode polymeric waveguide inside an optical backplane, which is embedded into PCB, 3) Optical slot and plug for high-density (channel pitch : 500 um) board-to-board interconnection. The polymeric waveguide technology can be used for transmission of data between transmitter/receiver processing boards and backplane boards. The main components are low-loss tapered polymeric waveguides and a novel optical plug and slot for board-to-board interconnections, respectively. The transmitter/receiver processing boards are designed as plug types, and can be easily plugged-in and -out at an optical backplane board. The optical backplane boards are prepared by employing the lamination processes for conventional electrical PCBs. A practical optical backplane system was implemented with two processing boards and an optical backplane. As connection components between the transmitter/receiver processing boards and backplane board, optical slots made of a 90°-bending structure-embedded optical plug was used. A 10 Gb/s data link was successfully demonstrated. The bit error rate (BER) was determined and
is 5.6×10<sup>-9</sup>(@10Gb/s) and the BER of 8 Gb/s is < 10<sup>-12</sup>.
A novel optical PCB with transmitter/receiver system boards and optical bakcplane was prepared, which is board-to-board interconnection by optical plug and slot. We report an 8Gb/s PRBS NRZ data transmission between transmitter system board and optical backplane embedded multimode polymeric waveguide arrays. The basic concept of ETRI's optical PCB is as follows; 1) Metal optical bench is integrated with optoelectronic devices, driver and receiver circuits, polymeric waveguide and access line PCB module. 2) Multimode polymeric waveguide inside an optical backplane, which is embedded into PCB. 3) Optical slot and plug for high-density(channel pitch : 500um) board-to-board interconnection. The polymeric waveguide technology can be used for transmission of data on transmitter/ receiver system boards and for backplane interconnections. The main components are low-loss tapered polymeric waveguides and a novel optical plug and slot for board-to-board interconnections, respectively. The optical PCB is characteristic of low coupling loss, easy insertion/extraction of the boards and, especially, reliable optical coupling unaffected from external environment after board insertion.
A practical optical printed circuit board (PCB) was demonstrated, using a waveguide-embedded optical backplane and processing boards. The polymeric waveguide was produced by means of a hot embossing technique then embedded following a conventional lamination processes. The core size of waveguide was 100 x 60 μm<sup>2</sup> (input section), 60 x 60 μm<sup>2</sup> (output section), and the propagation loss of tapered polymeric waveguide was approximately 0.1 dB/cm at 850 nm. We prepared a optical backplane with polymeric waveguide by using conventional multilayer board lamination processes. The transmission power and dimension of the optical backplane was same as those of waveguide before lamination. A metal optical bench was used as a packaging die for the optical devices and the integrated circuit chips in both the transmitter and the receiver processing boards. We used a 1×4 850 nm VCSEL array with 2 dBm of output power for the transmitter and a PIN photodiode array for the receiver. We successfully demonstrated 8 Gb/s of data transmission between the transmitter processing board and the optical backplane board.