Holger Karstensen

Parallel optical link (PAROLI) for multichannel gigabit rate interconnections

A 12-fiber unidirectional parallel optical link (PAROLI) with discrete Tx and Rx modules is presented with a total bandwidth exceeding 12 Gbit/s. The Tx and Rx module dimensions are 50 mm length, 18 mm width, and 10.5 mm height. The packages have 72 pins with 0.65 mm pitch in surface mount technology. The optical port is an MT-compatible 62.5 /spl mu/m core graded-index multimode fiber array connector which is locked by a clip and can be unlocked without special tools. The supply voltage is 3.3 V. The electrical signal interface is compatible to the Low Voltage Differential Signal Standard (LVDS, IEEE P1596-3 standard).

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

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 >

Loss analysis of laser diode to single-mode fiber couplers with glass spheres or silicon plano-convex lenses

The single-mode laser diode to single-mode fiber coupling efficiency is analyzed for couplers with glass ball lenses and silicon plano-convex lenses, respectively. The contributions of the different origins of loss are given. It is found that in nearly all cases, most of the total loss is determined by the spherical aberration of the lends that collects the divergent laser diode (lens 1). This loss is calculated for a variety of glass ball lenses and silicon plano-convex lenses are shown to be dependent on the laser diode spot size (or divergence angle). The minimum loss of a coupling configuration is determined with good accuracy by the parameters of lens 1; a single additional parameter, the effective laser diode spot size (or effective divergence angle) for the laser diode; and the coupling arrangement. The calculated losses are compared with experimental values. In most cases, theory and measurement agree very well; differences are discussed. >

High-efficiency two lens laser diode to single-mode fiber coupler with a silicon plano convex lens

A theory for the calculation of the spherical aberration loss of silicon planoconvex lenses is presented. The aberration losses are calculated as a function of the lens parameters. Furthermore, a theory for the coupling efficiency of a laser diode to single-mode fiber for a coupling arrangement consisting of a silicon planoconvex lens and a glass ball lens is given. The theoretical predictions are in good agreement with measurements. Experimentally, a coupling efficiency of 72% (1.4-dB coupling loss) was achieved for a laser diode with farfield angles of 20 degrees *33 degrees FWHM and a not yet fully optimized silicon planoconvex lens. >

Parallel optical link for multichannel interconnections at gigabit rate

A 12-fiber unidirectional parallel optical link called PAROLI with discrete Tx and Rx modules and a total bandwidth exceeding 12 Gbits/s is presented. The Tx and Rx module dimensions are 50 mm length, 18 mm width, and 10.5 mm height. The packages have 72 pins with 0.65-mm pitch in surface mount technology. The optical port is an MT-compatible 62.5-mm core graded-index multimode fiber array connector. The supply voltage is 3.3 V. The electrical signal interface is compatible to the Low Voltage Differential Signal Standard (LVDS, IEEE P1596-3 standard).

DC-coupled parallel optical interconnect cable with fiber ribbon

The design, set-up, and characterisation of a fixed length multi-channel parallel optical interconnection cable with electrical connectors (miniature sub-D connectors) at either sides is presented. The link is electrically compatible to ECL voltage level. Ribbons of both standard 1.3 /spl mu/m single-mode and graded-index multimode fibers are used as interconnection medium. The laser diodes are GaAs SQW LD (single quantum well) with very low threshold current. The photodiodes are made of silicon. The number of channels is 4, an upgrading to 12 channels is also presented.<<ETX>>

Optical multichannel parallel chip-to-chip data distribution

The design and the modelling results of an 8 channel parallel optical chip to chip interconnection consisting of a laser diode (LD) array, a single-mode waveguide (WG) array, and a photodiode (PD) array with 8 channels each are presented. The separation of the channels is 125 im, so the overall width of the 8 channel line is only I mm. The electronic and the optoelectronic components will be mounted on a silicon substrate wafer and the waveguides on a second silicon wafer which will be fixed upside down on the substrate. The LDs are envisaged to be AlGaAs singlequantum well types though the first implementation will be realized with conventional A1GaAs MCRW semiconductor lasers with a wavelength of 0.85 rim. The PDs are fabricated in standard silicon technology, the silica WGs with the flame hydrolysis technique and reactive ion etching. The trade off between large fabrication tolerances and the desired high coupling efficiencies is discussed. Mounting techniques for the LD- and PD-arrays are presented. A comparison between this optical interconnection and an equivalent electrical one is given.

Parallel optical interconnect modules with multifiber connectors

The design, realisation, and characterisation of a multichannel DC-coupled parallel optical interconnection link with connectorized (pigtails) transmitter and receiver modules is reported. The link is electrically compatible to ECL voltage level, the aggregate data throughput is up to 12 Gbit/s (1 Gbit/s per channel). The transmitter modules consist of arrays of laser diodes with low threshold currents and 50 /spl Omega/ matching networks, the receiver modules of photodiode arrays and amplifier arrays. All the opto-electronic and electronic components are fabricated as arrays with a pitch of 250 /spl mu/m.<<ETX>>

Holographic optical elements for free-space clock distribution

Optical clock distribution is an attractive technique to avoid clock skew in highspeed digital systems. For short lengths free space distribution by holographic optical elements (HOE) has specific advantages. We will report on the requirements of the optical system in respect of necessary light power and its equipartition to the photoreceivers. We give an estimation for the maximum number for optical fanout con sidering especially ECL circuits. Specific system constraints lead to a certain layout for the whole arrangement. The realization of a distinct HOE type is carried out in form of a binary phase reflection HOE which is produced by dry etching of silicon. The measured diffraction efficiency is close to the theoretical limit.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

VCSELs for datacom applications

The use of oxide confined VCSELs in datacom applications is demonstrated. The devices exhibit low threshold currents of approximately 3 mA and low electrical series resistance of about 50 (Omega) . The emission wavelength is in the 850 nm range. Life times of the devices are several million hours under normal operating conditions. VCSEL arrays are employed in a high performance parallel optical link called PAROLITM. This optical ink provides 12 parallel channels with a total bandwidth exceeding 12 Gbit/s. The VCSELs optimized for the parallel optical link show excellent threshold current uniformity between channels of < 50 (mu) A. The array life time drops compared to a single device, but is still larger than 1 million hours.