VCSE laser transmitters for parallel data links

Banwell, T.C.; Lehmen, A. C. Von; Cordell, R.R.

doi:10.1109/3.199318

Cited by 21 publications

(7 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many systems utilise a monolithic array of semiconductor lasers to increase the capability and functionality of single channel systems [1][2][3][4]. Such systems are able to dramatically increase the amount of data that can be acquired within a certain time frame or the amount of time it takes to obtain a certain amount of data.…”

Section: Ocis Codesmentioning

confidence: 99%

“…Based on the results from other laser array based systems [2], it may also be expected that the heat generated by multiple lasers may decrease the performance of individual SM sensors. Surprisingly, we find that the signalto-noise ratio (SNR) of a monolithically integrated SM VCSEL sensor arrays is actually enhanced rather than reduced with multichannel operation.…”

Section: Ocis Codesmentioning

confidence: 99%

See 1 more Smart Citation

Self-mixing sensing system based on uncooled vertical-cavity surface-emitting laser array: linking multichannel operation and enhanced performance

et al. 2014

View full text Add to dashboard Cite

We compare the performance of a self-mixing (SM) sensing system based on an uncooled monolithic array of 24×1 vertical-cavity surface-emitting lasers (VCSELs) in two modes of operation: single active channel and the concurrent multichannel operation. We find that the signal-to-noise ratio of individual SM sensors in a VCSEL array is markedly improved by multichannel operation, as a consequence of the increased operational temperature of the sensors. The performance improvement can be further increased by manufacturing VCSEL arrays with smaller pitch. This has the potential to produce an imaging system with high spatial and temporal resolutions that can be operated without temperature stabilization.

show abstract

Section: Ocis Codesmentioning

confidence: 99%

Section: Ocis Codesmentioning

confidence: 99%

Self-mixing sensing system based on uncooled vertical-cavity surface-emitting laser array: linking multichannel operation and enhanced performance

et al. 2014

View full text Add to dashboard Cite

show abstract

“…For the research presented here, scalability of the process to 2 1000 VCSELS was considered the most important design specification [1 O]. Since VCSELS are high speed devices [1 1], the design of the VCSEL driver circuit appears to be the frequency limiting factor and new driver designs are eliminating this problem [2,12]. The other specifications appear to be more a function of the bonding technique and thus scalability to large size appears to be the primary limiting factor.. We have chosen to investigate bonding techniques that remove the substrate Ieaving individual VCSELS bonded to specific locations in the integrated circuit.…”

Section: General Fabrication Considerationsmentioning

confidence: 99%

Comparison of techniques for bonding VCSELs directly to ICs

Hayes

Wilmsen

et al. 1998

SPIE Proceedings

View full text Add to dashboard Cite

This paper reports the successful bonding of 8 x 8 and 4 x 4 VCSEL arrays to Si CMOS and GaAs MESFET integrated circuits and to GaAs substrates. Three different bonding techniques are demonstrated and their electrical, optical and lmechanical characteristics are compared. All three techniques remove the substrate from the VCSEL wafer, leaving individual VCSELS bonded directly to locations within the integrated circuit. L IntroductionVCSEL based smart pixel arrays are very desirable for parallel optoelectronic processing and board to board interconnection since they can overcome the electrical interconnect bandwidth bottleneck. The. integration of VCSELS with foundry fabricated integrated circuits is the key technology required to fabricate the smart pixels. For large arrays, the VCSELS need to be bonded directly to the pixels. This has the advantage of low parasitic capacitance, better optical alignment and higher scalability.' There have been a number of previous reports of techniques for bonding VCSEIJ to integrated circuits and other substrates. Pu et al. were the first to report the bonding of an array of VCSELS directly to a foundry fabricated integrated circuits [ 1]. The 8 x 8 array was bonded using a co-planar flip chip bonding process. More recently, Krishnamoorthy et al. reported bonding a 2 x 10 array of 970nm VCSELS to a CM(3S chip [2]. This was also a co-planar bonding process, however the substrate was not removed and the VCSELS emitted through the GaAs substrate. Both of these co-planar techniques were based on previous work on the bonding of SEED arrays [3,4]. Matsuo et al. [5] bonded a VCSEL wafer to a silicon substrate with poiyimide, removed the VCSEL substrate and processed the wafer in to individual VCSELS. Maracas and coworker [(5,7] used a probe transfer technique to place individual VCSELS on a CMOS chip and Smith and coworkers [8] used a fluidic self-alignment technique. These earlier reports showed that VCSELS were robust and could be transferred to another substrate without significant change in electrical/optical characteristics. McLaren et al. [9] reported the thermosonic bonding of an 8 x 8 array to a fused quartz substrate which enabled the VCSEL output to be viewed through the transparent quartz. 90pm square bonding pads on a 250pm pitch were used and the substrate was not removed. This paper reports three techniques for bonding arrays of individual VCSELS to integrated circuits. The optical and electrical measurements of these bonded structures are measured and results compared with each other and those reported by other research groups. II. General Fabrication ConsiderationsDesigning a process for bonding VCSELS directly to locations embedded in an integrated circuit requires making several fundamental fabrication decisions, such as 1) whether or not to remove the VCSEL substrate, 2) the method of current confinement in the VCSELS, 3) the wafer design and 4) the general bonding concept. These design decisions should be based on the specifications for speed of operation...

show abstract

“…Body: Many systems utilise a monolithic array of semiconductor lasers to increase the capability and functionality of single channel systems [81,83,194,195]. Such systems are able to dramatically increase the amount of data that can be acquired within a certain time frame or the amount of time it takes to obtain a certain amount of data.…”

Section: Introductionmentioning

confidence: 99%

“…Based on the results from other laser array based systems [195], it may also be expected that the heat generated by multiple lasers may decrease the performance of individual SM sensors. Surprisingly, we find that the signal-to-noise ratio (SNR) of a monolithically integrated SM VCSEL sensor arrays is actually enhanced rather than reduced with multichannel operation.…”

Section: Introductionmentioning

confidence: 99%

Skin cancer detection using laser imaging

Mowla¹

View full text Add to dashboard Cite

Endeavors to develop a non-invasive and reliable device to detect different types of skin cancer in its early stages have been undertaken over the past few years. Although some advances have been made towards such developments, there remains great scope for the development of a non-expensive, compact, reliable, safe, easy to use, fast, sensitive, and non-invasive device. This project will apply the innovative laser feedback interferometry (LFI) technique to skin cancer detection via laser imaging using near-infrared vertical cavity surface emitting lasers (VCSELs). In this project, the science behind lighttissue interactions has been explored and skin imaging modalities have been elaborately studied. As a result, LFI has been exploited in various configurations to image different modalities such as Doppler flowmetry and confocal reflectance. In addition to single modality imaging, dual-modality imaging has also been proposed and conducted experimentally, to image Doppler flowmetry and confocal reflectance at the same time, using an integrated LFI system. It is shown that dual-modality imaging can yield images with higher contrast which provide more information about morphological and functional characteristics of a target under test.In addition to two-dimensional LFI imaging, three-dimensional imaging systems have also been studied and employed in the laboratory. A tomographic image identifies tissue volume with altered optical properties due to cancerous or other malignant tissue processes. We applied the three-dimensional imaging system to different types of keratinocyte skin cancer phantoms and results show high level of sensitivity in providing tomographic images. Using high numerical aperture lenses, making images at resolutions down to micrometer scales is possible, which is promising for microscopy of biological structures.Furthermore, parallel LFI imaging using an array of 24 VCSELs was also studied theoretically and experimentally as a part of this work. A VCSEL array was used in a parallel read-out LFI imaging system to develop a fast and high resolution device, which eliminates the need to scan mechanically in one dimension.Investigating the complex interactions of the laser beam and tissue requires a powerful and robust simulation technique. Monte Carlo was used as a simulation technique to model the light-tissue interactions occurring in the optical systems in this work. Firstly, we tested and validated the Monte Carlo main engine which was developed in the group, by studying morphological aspects of the simulated and experimental signals in a laser Doppler velocimetry system, and deep insight into the nature of the LFI Doppler spectrum and further conclusions were drawn. Secondly, the Monte Carlo engine was used in iii modeling and analyzing of optical systems, in this work.We developed tissue phantom making techniques which were used to examine the experimental ideas in place of biological samples which are difficult to obtain and work with. Therefore, tissue phantom techniques were studie...

show abstract

VCSE laser transmitters for parallel data links

Cited by 21 publications

References 25 publications

Self-mixing sensing system based on uncooled vertical-cavity surface-emitting laser array: linking multichannel operation and enhanced performance

Self-mixing sensing system based on uncooled vertical-cavity surface-emitting laser array: linking multichannel operation and enhanced performance

Comparison of techniques for bonding VCSELs directly to ICs

Skin cancer detection using laser imaging

Contact Info

Product

Resources

About