Parallel Optical Data Links Research Articles

70-Gb/s Multicore Multimode Fiber Transmissions for Optical Data Links

This letter describes a novel structure and crosstalk characteristics of a graded-index multicore fiber with seven cores arranged in a hexagonal array. A total of 70 Gb/s (7 × 10 Gb/s) is transmitted over a single 100-m seven-core multimode fiber (MMF) using tapered multicore fiber connectors and 850-nm vertical-cavity surface-emitting lasers, demonstrating high-speed multicore MMF transmissions for parallel optical data links.

Experimental techniques using optically enabled ring oscillators.

We present a method for characterizing transceiver performance in parallel optical data links. By establishing a bidirectional link between two optically enabled chips, the conditions for a ring oscillator are made possible. We propose this technique as a means of measuring the sensitivity of transceiver latency to controlled variables such as temperature, optical output power, supply voltage, and device misalignment. This method is noninvasive and independent of the packaging, circuit topology, and optical medium used. The technique is demonstrated experimentally, and results are compared with a simulation.

Imaging with microstructured polymer fibre

The imaging capabilities of a multicore microstructured polymer optical fibre with a square array of 112 air holes are demonstrated. Coherent imaging is achieved either by guiding light in polymer cores between air holes, or by guiding light in the air channels themselves. This potentially provides a miniaturised endoscope for medical applications, or a two-dimensional parallel optical data link for high-bandwidth interconnects.

Two-dimensional erbium-doped image fiber amplifier (EDIFA)

Two-dimensional (2-D) erbium (Er)-doped image fiber amplifiers (EDIFAs) mere fabricated for the first time. The measured gain characteristics showed the applicability of optical amplifiers to 2-D high-throughput parallel optical data links. Additionally, we discuss pumping methods for the EDIFAs. Issues to achieve higher gain EDIFAs are addressed.

Skew characteristics of image fiber for high-speed 2-D parallel optical data link

Skew of an image fiber, which has more than ten thousands of cores in a common cladding, was measured by a novel measurement method for the first time. This method can measure the time-of-flight difference between individual cores over the whole area of an image circle. The measurement result reveals that a test 100-m-long image fiber has skew of 5 ps/m, and the time-of-flight distributes randomly in the whole area of the image circle due to nonuniformity of the core dimension. It is also experimentally shown that the skew of an image fiber increases by bending. The theoretical analysis reveals that the bending-induced skew depends neither on the radius of curvature nor the shape of the curve but it depends only on the number of turns it is wound. The numerical calculation of skew by using typical parameters of image fibers shows that the winding have to be restricted to less than five turns to achieve a transmission speed of over 1 Gb/s/ch. Finally, we propose a twisted image fiber and an 8-shaped bobbin to suppress the skew due to bending.

MSM photodetector fabricated on polycrystalline silicon

Interdigitated metal-semiconductor-metal (MSM) photodetectors were fabricated by depositing metal contacts on top of a 2-μm-thick layer of polycrystalline silicon (polysilicon). These detectors have a -3-dB bandwidth of 750 MHz and a responsivity of 0.13 A/W at 860 nm. The bandwidth is more than twice that reported for conventional silicon MSM photodetectors as a result of the thin absorbing layer made possible by the higher optical absorption of polysilicon. A simple fabrication process that is compatible with standard VLSI processes, together with good performance characteristics, make this an ideal detector for integrated optoelectronic receivers for use in short distance, parallel optical data links.

Microcavity LED-based parallel data link using small-diameter (125 m) plastic optical fibres

Parallel optical data links using high-efficiency microcavity LEDs (MCLEDs) and small-diameter plastic optical fibre ribbons are proposed. MCLED performance, coupling efficiencies, alignment tolerances, plastic optical fibre end-facet termination techniques and first link experiments are studied.

Vertical cavity surface emitting laser-based parallel optical data link

Vertical cavity surface emitting laser (VCSEL) arrays are designed and used for 10-channel parallel optical data links, OPTOBUS™, to transmit data at a speed of up to 800 Mbits/s per channel. The interface between the VCSELs and the optical fiber ribbons is based on molded plastic waveguide technology. A bit error rate of 10-15 is demonstrated.

622 Mb/s/channel parallel digital optical receiver array module using hybrid packaging

Given the high data rates (>500 Mb/s) achievable in optical links using current device technologies, low cost packaging of transmitters and receivers plays a key role in rendering them viable for short-haul data communication networks. The authors report a 12 channel, fully digital, hybrid receiver module for a synchronous parallel optical datalink operating at 622 Mb/s/channel. The use of a multichip module (MCM) and the passive alignment of the MT-connectorized multimode ribbon fiber to the photodetector array resulted in a simple low cost packaging solution.

Multichannel parallel data link for optical communication

The MODLINK (multichannel parallel optical data link) system is described. It provides 12 parallel data channels; one channel may be used for clock signal, and provisions are made for synchronizing the data channels with the clock. Additional MODLINK units can be linked in parallel for more channels. The system can handle data rates from DC to 200 Mb/s/channel in continuous or burst mode. Since this system is burst-mode compatible, data signal encoding is not required and clock recovery is optional. The transmitter and receiver systems are presented in detail. System performance is examined with respect to the thermal characteristics of the transmitter package, interchannel crosstalk in the transmitter, receiver sensitivity and interchannel crosstalk, and long-distance transmission.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>