2009
Book chapter: Packaging of Optical Components and Systems
Wiley Encyclopedia of Electrical and Electronics Engineering
Dec 27, 2009
In this article, several types of semiconductor optical components are introduced, and packaging of optical components and systems will be discussed. Specifically, three common types of optical sources will be addressed: light emitting diodes (LED), edge-emitting semiconductor lasers, and vertical cavity surface emitting lasers (VCSEL).
DOI: 10.1002/047134608X.W21062002
Book chapter: "Optical sources: Light-emitting diodes and laser technology"
Academic Press (1998, 2002); ISBN: 0-12-207892-6; Handbook of Fiber Optic Data Communication By Casimer DeCusatis
Feb 2002
The Handbook includes chapters on all the major industry standards, quick reference tables, helpful appendices, plus a new glossary and list of acronyms. This practical handbook can stand alone or as a companion volume to DeCusatis: Fiber Optic Data Communication: Technological Advances and Trends (February 2002, ISBN: 0-12-207892-6), which was developed in tandem with this book.
- Includes emerging technologies such as Infiniband, 10 Gigabit Ethernet, and MPLS Optical Switching
- Describes leading edge commercial products, including LEAF and MetroCore fibers, dense wavelength multiplexing, and Small Form Factor transceiver packages
- Covers all major industry standards, often written by the same people who designed the standards themselves
- Covers all major industry standards, often written by the same people who designed the standards themselves
- Includes an expanded listing of references on the World Wide Web, plus hard-to-find references for international, homologation, and type approval requirements
- Convenient tables of key optical datacom parameters and glossary with hundreds of definitions and acronyms
- Industry buzzwords explained, including SAN, NAS, and MAN networking
- Datacom market analysis and future projections from industry leading forecasters
1998
Paper: Vertical cavity surface emitting laser-based parallel optical data link
Optical Engineering, vol 37, no. 12, pp.3113-18, Dec. 1998
Dec 1998
Vertical cavity surface emitting laser (VCSEL) arrays are designed and used for 10-channel parallel optical data links. OPTOBUSTM, 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.
DOI: 10.1117/1.601986
Paper: Automatic power control of a VCSEL using an angled lid TO56 package
1998 Proceedings. 48th Electronic Components and Technology Conference
May 1998
Many applications of semiconductor lasers require that the output power from the laser is maintained at a fixed level independent of temperature and aging, this is typically accomplished with edge emitting lasers using a back facet monitor photodiode which is incorporated into the laser package. The signal from the photodiode is used to drive the feedback control circuit. In the absence of a back facet it is necessary to develop an alternate packaging scheme for VCSELs that allows for the generation of a signal for use in maintaining a fixed output power. In this; paper we present a VCSEL packaged in a TO56 can with a silicon pin photodetector. A portion of the emitted beam from the VCSEL is reflected from the lid onto the photodetector. Results demonstrating an auto-power control capability of f3percent are presented.
DOI: 10.1109/ECTC.1998.678694
Paper: VCSEL devices and packaging
Proceedings of SPIE, ISSN 0277-786X, 05/2003, Volume 3289, Issue 1
Jan 1998
Over the last few years, Motorola has been applying a different kind of semiconductor laser technology to a family of datalink and discrete products. The laser technology is commonly referred to as Vertical Cavity Surface Emitting Lasers (VCSELs). This technology is now emerging from advanced development and research laboratories into the market place, and there is a number of introductory texts, inaddition to journal articles that describe the technology [1]. Motorola, has chosen the VCSEL technology to be the back-bone of it's optical program and has developed products such as the OPTOBUSTM datalink [1,2,3], which interconnects arrays of VCSELs inside a small, compact module via parallel fiber ways to package the VCSELs. This paper will detail, inaddition to the packaging used in OPTOBUSTM, two approaches to discrete VCSEL packaging that are commercially competitive; the flip-chip and the angled angle TO-can. The essence of both these package designs is what is usually termed as 'auto-power control' (APC). This allows a feedback mechanism to feedback a signal to the laser, to control or change its output power level with respect to system conditions. Usually, this is accomplished by back facet monitor photodetectors in conventional edge emitting laser systems. As the VCSEL does not have facets, alternative solutions have to developed; the flip-chip and angled TO-can are shown to be good candidates.
DOI: 10.1117/12.3054701997
Paper: Vertical cavity surface emitting laser packaging with auto power control
Electronic Components and Technology Conference, 1997. Proceedings., 47th
May 18, 1997
We will discuss a discrete VCSEL packaging method using a monitoring photodiode for auto power control. We have demonstrated a VCSEL package with an output power variation within +1% over a temperature range from 0 to 65OC. Introduction Semiconductor laser output power varies with temperature and degrades with duration of operation. Many applications, such as CD-ROMs, bar code scanners, and high speed data communications, require a semiconductor laser to maintain a constant output power across a temperature range within a specified system operation lifetime. Since an edge emitting laser diode emits light from both facets, an autopower control (APC) scheme can be implemented by monitoring the laser emission from the back facet of the laser. Even though vertical cavity surface emitting laser (VCSEL) output power is less sensitive to temperature, and VCSEL's without APC have been used for some relatively low speed data communications [1], further expanding the VCSEL application scope requires packaging a VCSEL with APC capability.
DOI: 10.1109/ECTC.1997.606195
Paper: Characteristics of VCSELs and VCSEL arrays for optical data links
Proc. SPIE 3004, Fabrication, Testing, and Reliability of Semiconductor Lasers II, 122 (May 1, 1997)
Feb 1997
High performance, low cost, and highly reliable vertical cavity surface emitting lasers (VCSELs) have been developed and are currently being used in both parallel and serial optical interconnect applications. For example, Motorola's OPTOBUSTM parallel optical interconnect relies heavily on the unique characteristics of arrays of GaAs based VCSELs emitting at 850 nm to achieve its stringent performance goals at low cost. Representative parametric results of discrete VCSELs and VCSEL arrays will be compared, including `optical power output-current' and `current-voltage' curves, optical wall plug efficiencies, and modulation characteristics. The use of statistical parameter analysis across a wafer and subsequent parametric wafer maps has proven to be a valuable tool for maintaining control of the fabrication process. The consistency of VCSEL parameters across individual VCSEL arrays will be discussed. VCSELs are very robust devices. Life times at room ambient in excess of 3E6 hours have been reported by several groups. Degradation behavior of selected device parameters will be discussed. Failure analysis demonstrating the effect of proton implant depth on reliability will be presented. ESD damage at forward bias is shown to be process related, while ESD damage at reverse bias is shown to be material related. These VCSELs are ESD Class 1 devices.
DOI: 10.1117/12.273825
Paper: Relative intensity noise of 780nm vertical cavity surface emitting lasers
Proceedings of the 1997 Pacific Rim Conference on Lasers and Electro-Optics, CLEO/Pacific Rim, No 46984, Jan 1997
Jan 1997
Vertical cavity surface emitting lasers (VCSELs) have been proposed for appli- cations in optical data storage.’ An optical pickup using a VCSEL can be made compact due to the nature of its emission direction. The low power consumption of a VCSEL based optical pickup makes it attractive for portable consumer electron- ics and laptop computers that are pow- ered by batteries. However, the VCSEL noise behavior is of a concern for high quality data storage. Typically, a signal- to-noise ratio (S/N) of at least 80 dB, or a relative intensity noise (RIN) of -120 dB/Hz, is needed for applications in compact disk ( C D ) video. We report an etched mesa structure VCSEL at 780 nm with an SIN of better than 100 dB, or a RIN of below -140 dBIHz.
Paper: Effect of proton implantation on the degradation of GaAs/AlGaAs vertical cavity surface emitting lasers
Electronics Letters, ISSN 0013-5194, 1997, Volume 33, Issue 2, p. 137
1997
Vertical cavity surface emitting lasers (VCSELs) have been proposed for appli- cations in optical data storage.’ An optical pickup using a VCSEL can be made compact due to the nature of its emission direction. The low power consumption of a VCSEL based optical pickup makes it attractive for portable consumer electron- ics and laptop computers that are pow- ered by batteries. However, the VCSEL noise behavior is of a concern for high quality data storage. Typically, a signal- to-noise ratio (S/N) of at least 80 dB, or a relative intensity noise (RIN) of -120 dB/Hz, is needed for applications in compact disk ( C D ) video. We report an etched mesa structure VCSEL at 780 nm with an SIN of better than 100 dB, or a RIN of below -140 dBIHz.
DOI: 10.1049/el:199700881996
Invited talk and abstract: Vertical cavity surface emitting lasers for communication applications
Optical Society of America (OSA) Annual meetings, proceedings, paper WR1, Rochester, NY
Oct 1996
Paper: Use of VCSEL arrays for parallel optical interconnects
Proc. SPIE 2683, Fabrication, Testing, and Reliability of Semiconductor Lasers
Apr 10, 1996
The use of vertical cavity surface emitting lasers (VCSELs) in a parallel optical interconnect for Motorola's OPTOBUSTM interconnect was made public over 1 year ago. This was the first time VCSELs were introduced into a product which took advantage of the excellent qualities of VCSELs over edge-emitting lasers. Motorola's OPTOBUSTM interconnect is a ten channel parallel bi-directional data link based on two 10 channel multimode fiber ribbons. One of the key differences in this type of interconnect compared with previous data link designs is the use of the VCSELs as the optical source for the link's fiber optic transmitter. A single 1 X 10 VCSEL array from a GaAs wafer is die attached to a 10 channel GUIDECASTTM optical interface unit which couples the emission from each laser device to its corresponding fiber ribbon channel and thus negates the use of expensive manufacturing techniques such as active alignment and pig-tailing. The OPTOBUSTM interconnect achieves its performance goals (which include low cost) via the unique characteristics of the GaAs VCSELs arrays. For example, the 850 nm devices produce a circular symmetric beam with a half angle of about 10 degrees allowing the coupling loss into the waveguide to be less than 3 dB. In addition, to maintain low manufacturing costs, each VCSEL array is individually and automatically probe tested (just as in the silicon industry) to verify that each VCSEL achieves the OPTOBUSTM interconnect's stringent electrical, optical, thermal and mechanical specifications. Typical computer generated wafer maps from automated production tooling and statistical parametric results are discussed. The combination of low threshold currents with superior thermal and optical performance allow the devices to be modulated under fixed bias conditions. Typical drive currents of 3X threshold are used to obtain nominal FDA Class 1 safety optical power levels from the GUIDECASTTM optical interface unit.
DOI: 10.1117/12.237679
Paper: Key challenges and results of VCSELs in data links
Conference Proceedings LEOS'96 9th Annual Meeting IEEE Lasers and Electro-Optics Society
1996
Vertical cavity surface emitting lasers (VCSELs) have proven to be the preferred laser device structure for most implementations of parallel optical interconnects. The advantage of using VCSEL technology is demonstrated in Motorola's OPTOBUSTM interconnect, which is a ten channel parallel bi-directional data link based on two 10 channel multimode fiber ribbons. In the OPTOBUSTM interconnect a single 1x10 GaAs VCSEL array is die attached to a 10 channel GUIDECASTTM optical interface unit which directly couples the emission from each laser device to its corresponding fiber ribbon channel and thus eliminates the need for active alignment and pig-tailing. The unique characteristics of VCSEL arrays are instrumental in achieving a low cost, high performance interconnect. For example, the 850 nm devices produce a circular symmetric beam with a narrow half angle allowing the coupling loss into the waveguide to be less than 3 dB. In addition, each VCSEL array is individually and automatically probe tested to verify that each VCSEL achieves the OPTOBUSTM interconnect's stringent electrical, optical, thermal and mechanical specifications. Automated wafer maps and statistical parametric analysis result in a well controlled, low cost process. The devices can be modulated under fixed bias conditions due to their low threshold currents in combination with superior thermal and optical performance. Typical drive currents of 3X threshold are used to obtain nominal FDA Class 1 safety optical power levels from the GUIDECASTTM optical interface unit.
DOI: 10.1109/LEOS.1996.5716041995
Paper: Parallel optical interconnects using VCSELs
Proceedings IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits
1995
OptobusTM is a ten channel parallel bi-directional datalink based on multimode fiber ribbons. The design represents a series of tradeoffs between cost and performance to produce a low cost interconnect solution with a minimum of 1.5 Gbit/s of aggregate throughput. The wide spread utilization of fiber optics as a system level interconnect has been inhibited by the failure of existing solutions to better the price performance of copper. A useful metric in comparing interconnect solutions is the price of a bi-directional connection divided by its bandwidth. In a compilation of this metric across multiple technologies one feature stands out: a price/performance barrier at about $300/Gbit. The focus of Motorola’s OptobusTM program is breaking through this barrier by developing a fiber ribbon based interconnect designed for volume manufacturing. The bulk of this paper is devoted to the analyzing the trade-off between manufacturability and performance in the design of Optobus. The Optobus program is prototyping a 10 channel bi-directional data link. A ‘link’ consists of a pair of ten channel connectorized fiber ribbons and two multi-chip modules packaged as PGAs. The modules run from a single 5V supply and can be directly interfaced to differential PECL levels. The MT connectorized fiber ribbons mate to a pair of ten channel optical ports on the module, one containing ten receiver channels and the other ten transmitter channels. The link is purely transparent, that is, neither clock nor coding are required and the user’s timing is retained. Optobus’s design goal is for the system designer to be able to treat the link as a delay determined by the length of the fiber ribbon.
DOI: 10.1109/CORNEL.1995.482526