22 Gb/s error-free data transmission beyond 1 km of multi-mode fiber using 850 nm VCSELs

The first error-free data transmission beyond 1 km of multi-mode fiber at bit-rates exceeding 20 Gb/s is demonstrated using a high modulation bandwidth, quasi-single mode (SMSR similar to 20 dB) 850 nm VCSEL. A VCSEL with small similar to 3 mu m aperture shows quasi-single mode operation with a narrow spectral width. The top mirror reflectivity of the VCSEL is optimized for high speed and high output power by shallow etching. A combination of narrow spectral width and high optical power reduces the effects of fiber dispersion and fiber and connector losses and enables such a long transmission distance at high bit-rates

High Speed VCSELs and VCSEL Arrays for Single and Multicore Fiber Interconnects

Our recent work on high speed 850 nm VCSELs and VCSEL arrays is reviewed. With a modulation bandwidth approaching 30 GHz, our VCSELs have enabled transmitters and links operating at data rates in excess of 70 Gbps (at IBM) and transmission over onboard polymer waveguides at 40 Gbps ( at University of Cambridge). VCSELs with an integrated mode filter for single mode emission have enabled transmission at 25 Gbps over > 1 km of multimode fiber and a speed-distance product of 40 Gbps . km. Dense VCSEL arrays for multicore fiber interconnects have demonstrated 240 Gbps aggregate capacity with excellent uniformity and low crosstalk between the 40 Gbps channels

Dynamic properties of silicon-integrated short-wavelength hybrid-cavity VCSEL

We present a vertical-cavity surface-emitting laser (VCSEL) where a GaAs-based "half-VCSEL" is attached to a dielectric distributed Bragg reflector on silicon using ultra-thin divinylsiloxane-bis-benzocyclobutene (DVS-BCB) adhesive bonding, creating a hybrid cavity where the optical field extends over both the GaAs- and the Si-based parts of the cavity. A VCSEL with an oxide aperture diameter of 5 mu m and a threshold current of 0.4 mA provides 0.6 mW output power at 845 nm. The VCSEL exhibits a modulation bandwidth of 11 GHz and can transmit data up to 20 Gbps

III-V-on-silicon photonic devices for optical communication and sensing

In the paper, we review our work on heterogeneous III-V-on-silicon photonic components and circuits for applications in optical communication and sensing. We elaborate on the integration strategy and describe a broad range of devices realized on this platform covering a wavelength range from 850 nm to 3.85 μm

Integration of 150 Gbps/fiber optical engines based on multicore fibers and 6-channel VCSELs and PDs

Multicore fiber enables a parallel optic data link with a single optical fiber, thus providing an attractive way to increase the total throughput and the integration density of the interconnections. We study and present photonics integration technologies and optical coupling approaches for multicore transmitter and receiver subassemblies. Such optical engines are implemented and characterized using multimode 6-core fibers and multicore-optimized active devices: 850-nm VCSEL and PD arrays with circular layout and multi-channel driver and receiver ICs. They are developed for bit-rates of 25 Gbps/channel and beyond, i.e. <150 Gbps per fiber, and also optimized for ruggedized transceivers with extended operation temperature range, for harsh environment applications, including space

40 Gb/s data transmission over a 1-m-long multimode polymer spiral waveguide for board-level optical interconnects

Optical interconnects have attracted considerable attention for use in short-reach communication links within high performance electronic systems, such as data centres, supercomputers and data storage systems. Multimode polymer waveguides in particular, constitute an attractive technology for use in board-level interconnects as they can be cost-effectively integrated onto standard PCBs and allow system assembly with relaxed alignment tolerances. However, their highly-multimoded nature raises important concerns about their bandwidth limitations and their potential to support very high on-board data rates. In this paper, we report record error-free (BER<10-12) 40 Gb/s data transmission over a 1 m long multimode polymer spiral waveguide and present thorough studies on the waveguide bandwidth performance. The frequency response of the waveguide is investigated under a wide range of launch conditions and in the presence of input spatial offsets which are expected to be highly-likely in real-world systems. A robust bandwidth performance is observed with a bandwidth-length product of at least 35 GHz×m for all launch conditions studied. The reported results clearly demonstrate the potential of this technology for use in board-level interconnects, and indicate that data rates of at least 40 Gb/s are feasible over waveguide lengths of 1 m.This work was supported by the U.K. EPSRC through the Centre for Advanced Photonics and Electronics (CAPE), and the Swedish Foundation for Strategic Research.This is the final version of the article. It was first published by IEEE at http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=696085

Theory and simulation of subwavelength high contrast gratings and their applications in vertical-cavity surface-emitting laser devices

This work intends to fully explore the qualities and applications of subwavelength gratings. Subwavelength gratings are diffraction gratings with physical dimensions less than the wavelength of incident light. It has been found that by tailoring specific dimension parameters, a number of different reflection profiles can be attained by these structures including high reflectivity or low reflectivity with broad and narrow spectral responses. In the course of this thesis the physical basis for this phenomenon will be presented as well as a mathematical derivation. After discussion of the mechanics of the reflection behavior, the methods used in modeling subwavelength gratings and designing them for specific functions will be explored. Following this, the fundamentals of vertical-cavity surface-emitting lasers (VCSELs) will be discussed, and the applications of subwavelength gratings when used with these lasers will follow. Several devices, both theoretical proposals and fabricated examples, will be presented in addition to the available performance measurements. Finally, the fabrication challenges that restrict subwavelength gratings from adoption as standard components in VCSEL design will be considered with regard to ongoing fabrication research