Takahiro Matsubara

Three dimensional optical interconnect on organic circuit board

We propose high speed optical interconnection which is three dimensional optical lanes using polymer materials fabricated on an organic circuit board with metal lines and pads. These optical lanes transmit optical signals not only on a plane surface but into the other side of a circuit board. It has following three particular portions; (1) curved parallel optical waveguide; (2) 45 degree reflection mirror; (3) optical via hole. Four channel three dimensional optical lanes with current electrical lines and pads are newly developed on the organic circuit board named CPCoretrade. We characterize the optical lanes by transmission loss and passed through eye diagram, and optical signal transmission is confirmed. Then optical signal transmission up to 3Gbps/channel are demonstrated with 850nm VCSEL flip-attached on the circuit board with active and passive electronic devices and components as driving circuit

Development of optical multi-channel connector for rigid waveguide — Fiber optical interconnection

We propose a newly developed optical multi-channel connector to connect a rigid optical waveguide array and an optical fiber array for an on-board optical interconnection. The prototype of a 24-channel optical card edge connector to connect between a rigid multimode waveguide array fabricated onto a substrate and a multi-mode fiber array is manufactured, and two types of optical connection losses are defined and evaluated by the direction of the optical signal. The optical connection losses from the waveguide to the fiber as transmitting function and from the fiber to the waveguide as receiving function, are less than 0.7 dB and 0.6 dB, respectively.

Three-dimensional optical lines fabricated onto substrate for on-board interconnection

Optical lines using polymer materials fabricated on an organic substrate with metal lines and pads are proposed to realize fully optical interconnections among high performance LSIs. This optical line enable transmit high speed optical signals not only on a plane surface but to vertical direction. It has following four particular portions; (1) Curved parallel optical waveguide; (2) 45 degree reflection mirror; (3) Optical via hole with coaxial structure; (4) Optical joint between package and board. The optical line characterized by transmission loss and passed through eye diagram, and good optical signal transmission is confirmed to really use for optical interconnection between LSIs. Then on-board optical signal transmission is demonstrated by that VCSEL and PIN-PD are assembled using flip-chip technology on a circuit board with other electric devices of driving circuit, and also package-to-board optical joint are demonstrated by passing through solder reflow process.

Surface mountable package (OptoBGA/sup TM/) for 10 G data link

In an effort to provide a breakthrough in next-generation fiber optic data links, a new type of opto-electronic package has been developed using ceramic BGA technology (OptoBGA/sup TM/). In this paper, we describe how the OptoBGA/sup TM/ has adequate electrical performance meeting OC-192 or other 10 Gbs transmission specifications. For demonstration, a 10 G serial transmitter is designed and tested to achieve sufficient electrical eye opening of LD driver output when compared to its specifications (LD driver-pulse transient time 35 ps, Imod=100 mA, 20-80%).

Optical multi-channel connector for rigid waveguide and fiber connection

We propose a newly developed optical multi-channel card edge connector to connect a rigid optical waveguide array fabricated onto a substrate and an optical fiber array for an on-board optical interconnection. The receptacle is placed at the edge of the waveguide and is mechanically aligned to alignment studs directly formed precisely onto the optical waveguide. The plug terminates the optical fiber ribbon using a plastic ferrule, and the ferrule is pushed to the end face of the waveguide using springs for physical contact. The plug is inserted into the housing and is latched by a single action. The connection losses of 12 channel optical card edge connector are 0.8 dB on the waveguide in the GI-50/125 fiber direction, and 1.1 dB on the fiber in the waveguide direction.

Development of OE integrated surface mount packaging

In an effort to provide a breakthrough in next-generation fiber optic data links, we are proposing a concept in optics and electronics (OE) integrated surface mount packaging technology. It can provide more compact and easier assembly of optoelectronics packaging. One assembly issue of surface mount packaging is being able to secure high bit rate transmission lines from board level to optics mount level as well as optical connectivity on the board. In this paper, we describe how a flat lead type surface mount package utilizing RF vias, which has broadband characteristics and provides high performance, low distortion of the pulse waveform, and low jitter, from active devices. For a demonstration, we evaluated actual EO modules using 2 mm length RF vias, enabling a receptacle such as an SC type to be attached. Measurement results of electrical/optical eye diagram tests were very close to the theoretical expectations. Therefore, we believe that the technology is a positive solution to develop downsizing and mass-productivity of optoelectronics packaging.

High reliability pre-mold package with optical fiber guide pipe

A pre-mold package with optical fiber guide pipe has been developed to supply the low cost package for the access network systems market. This paper describes the PD module utilizing the premold package which has a very low variation of dark current after the reliability test. It is very close to that of TO-CAN type PD. In this paper, we propose the premold package to meet the market requirements offering low cost and high reliability solution.