The benefits of ultrashort optical pulses in optically interconnected systems

Abstract

Many properties of an optically interconnected system can be improved through the use of a modelocked laser. The short pulse duration, high peak power, wide spectral bandwidth, and low timing jitter of such a laser lead to these benefits. Timing advantages include simplified synchronization across large chip areas, receiver latency reduction, and data resynchronization. Lower power dissipation may be achieved through improved receiver sensitivity. Additional applications of short optical pulses include time-division multiplexing, single-source wavelength-division multiplexing, and precise time-domain testing of circuits. Several of these concepts were investigated using a high-speed chip-to-chip optical interconnect demonstration link. The link employs a modelocked laser and surface-normal optoelectronic modulators that were flip-chip bonded to silicon CMOS circuits. This paper outlines experiments that were performed on or simulated for the link, and discusses the important benefits of ultrashort optical pulses for optical interconnection.

A 90nm CMOS 16Gb/s Transceiver for Optical Interconnects

“…In addition, a minimum signal-tonoise ratio (SNR) must be maintained in order to achieve a given BER and the interference associated with the average current variation, , must be accounted. Combining these terms results in a total minimum voltage swing per bit of (6) where is the total input voltage noise variance which is computed by input referring the receiver segment circuit noise and the effective clock jitter noise.…”

“…The negligible frequency dependent loss of optical channels provides the potential for optical link designs to fully leverage increased data rates provided through CMOS technology scaling without excessive equalization complexity. Optics also allows very high information density in both free space systems [6]- [8], with the ability to focus short wavelength optical beams into small areas without the crosstalk issues of electrical links, and in fiber based systems, with the added dimension of wavelength division multiplexing (WDM) [9].…”

15-gb/s bit-interleaved optical backplane bus using volume photopolymer holograms

“…The BIOB can also be implemented using a pulse laser, which is adopted in optical time-division-multiplexing technology in the telecom industry [7] with electroabsorption modulators [8], [9] for ultrahigh-speed operation. Because confidential data can be separately distributed into multiple storage devices working in an array format, a benefit of security and enhanced reliability is achieved in addition to the potential to boost system speed and relieve wiring congestion.…”

Monolithic passively mode-locked lasers using quantum-dot or quantum-well materials grown on GaAs substrates

“…There is renewed interest in semiconductor MLLs as sources for multi-gigahertz, ultra-short optical pulse generation. The compact size, low cost, low power consumption, and direct electrical pumping of semiconductor monolithic mode-locked lasers make them promising candidates for inter-chip/intra-chip clock distribution 3,4 as well as other applications including high bit-rate optical time division multiplexing 5,6,7,8,9 , high speed electro-optic sampling 10 , and impulse response measurement of optical components 1 . However, the compact diode laser pulse sources have generally not been able to match the pulse quality of the best mode-locked lasers 11 .…”