The challenges associated with the development of free-space optically interconnected electronics are discussed. These include finding an application for which optics offers an improved performance, developing optical transceivers, and developing suitable optics and mechanics. The main focus of the paper is the discussion of some novel approaches that smart pixels offer to increase alignment tolerance.

Challenges in optically interconnecting electronics

We propose utilizing a radio-over-fiber technique of optical subcarrier-multiplexing transmission for radio base stations (BSs) with adaptive array antennas. The proposed system can be constructed at low cost since only one optical transmitter and receiver is required for a center station and a BS. Moreover, relative phases among antenna branches are insensitive to equivalent length fluctuation of an optical fiber.

Optical subcarrier multiplexing transmission for base station with adaptive array antenna

A package is described that couples a twelve channel wide fiber optic cable to a twelve channel Vertical Cavity Surface Emitting Laser (VCSEL) transmitter and a multiple channel Perpendicularly Aligned Integrated Die (PAID) receiver. The package allows for reduction in the height of the assembly package by vertically orienting certain dies parallel to the fiber optic cable and horizontally orienting certain other dies. The assembly allows the vertically oriented optoelectronic dies to be perpendicularly attached to the horizontally oriented laminate via a flexible circuit.

Fiber optic connections and method for using same

The design, realization, and characterization of a multichannel dc-coupled ECL-voltage compatible parallel optical interconnection with a bit rate of up to 1 Gb/s-per-channel is reported. The transmitter module consists of an array of laser diodes with low threshold currents and the 50 /spl Omega/ matching network, the receiver module of a photo diode array and an amplifier array. All the opto-electronic and electronic components are fabricated as arrays with a pitch of 250 /spl mu/m. The total power consumption is 110 mW per channel, For a BER >

Parallel optical interconnection for uncoded data transmission with 1 Gb/s-per-channel capacity, high dynamic range, and low power consumption

A heat sink for a transceiver optoelectronic module including dual direct heat paths and a structure which encloses a number of chips having a central web which electrically isolates transmitter and receiver chips from each other. A retainer for an optical coupler having a port into which epoxy is poured. An overmolded base for an optoelectronic module having epoxy flow controller members built thereon. Assembly methods for an optoelectronic module including gap setting and variation of a TAB bonding process.

Assembly of opto-electronic module with improved heat sink

Synchronous parallel optical-fiber transmission is an attractive method for providing increased interconnection throughput and higher density in advanced information systems. Skew suppression (reducing transmission delay time variation), error-free fully DC-coupled data transmission capability, compactness, and low power consumption of modules are important requirements. In order to meet these requirements, we developed optical subsystem interconnections using long-wavelength laser diode arrays and single-mode fiber arrays. The major design criteria are discussed, especially as they are related to skew due to laser diode turn-on delay and receiver input optical power variation. The use of low-threshold-current laser diode arrays is an important design requirement. Based on the design criteria discussed in this work, we demonstrated and channel 200-Mb/s/ch 100-m transmission using compact (0.18 cc/ch/module), low power (total 280 mW/ch), fully integrated transmitter and receiver modules with an ECL (emitter coupled logic) interface. These modules include our new laser diode arrays with low threshold current of 3.2 mA. Performance results showed that these modules are very effective as interconnections between synchronously operating subsystems. >

H. Kodera

Papers

200-Mb/s/ch 100-m optical subsystem interconnections using 8-channel 1.3-/spl mu/m laser diode arrays and single-mode fiber arrays