High Speed Vertical Cavity Surface Emitting Laser (VCSEL)
Navy STTR 20.B - Topic N20B-T027
Naval Air Systems Command (NAVAIR) - Ms. Donna Attick [email protected]
Opens: June 3, 2020 - Closes: July 2, 2020 (12:00 p.m. ET)
N20B-T027 TITLE: High Speed Vertical Cavity Surface Emitting Laser (VCSEL)
RT&L FOCUS AREA(S): General Warfighting Requirements (GWR)
TECHNOLOGY AREA(S): Electronics, Air Platform, Ground Sea
OBJECTIVE: Develop and package an uncooled vertical cavity surface emitting laser (VCSEL) that operates error free in a fiber optic transmitter at no less than 100 gigabits per second binary non-return to zero serial for air platform fiber optic link applications.
DESCRIPTION: Current airborne military (mil-aero) core avionics, electro-optic (EO), communications and electronic warfare systems require ever-increasing bandwidths while simultaneously demanding reductions in space, weight and power. The replacement of shielded twisted pair wire and coaxial cable with earlier generation length-bandwidth product multimode optical fiber has given increased immunity to electromagnetic interference, bandwidth, and throughput, and a reduction in size and weight on aircraft.
For Ethernet, the serial rate using binary non-return to zero signaling for multimode fiber links has increased from 1 gigabit per second in 1998 to 25 gigabits per second in 2015 [Ref 1]. To meet commercial sector demands for higher aggregate bandwidth capacity, optical interconnects based on 850 nanometers (nm) VCSELs have evolved to higher lane rates, more parallel architectures, and more advanced modulation formats [Ref 2]. Digital fiber optic transmitters employing VCSELs have been shown to operate reliably at extended temperatures (-40 to +85-degrees Celsius) without active cooling. Current digital fiber optic transmitters consist of an uncooled VCSEL operating at 850 nm wavelength and custom designed integrated circuitry (IC) to drive the VCSEL. The IC includes electrical waveform shaping to improve the signal response of the VCSEL. A slightly overdamped frequency response can limit the amount of optical overshoot and but can be effectively controlled with electrical pre-emphasis [Ref 3]. Oxide confined VCSELs have been matured for use in digital multimode fiber optic links up to about 50 gigabits per second [Refs 4-5]. Microwave and optical test procedures have evolved to characterize VCSEL responses including relative intensity noise, optical modulation response (scattering parameter 21 (S21)), and high-resolution optical spectra [Ref 6]. Research is ongoing exploring more advanced VCSEL technology [Ref. 7].
Historically, avionics has mostly preferred the use of conventional binary non-return to zero serial/single lane links over higher numbered lane links, parallel links, pulse amplitude modulated links and wavelength division multiplexed links. To meet the expected growth in aggregate bandwidth required onboard future generation aircraft, new optical component technologies that enable much higher speed binary non-return to zero serial links will be required. It is envisioned that a VCSEL based transmitter operating in a single lane at no less than 100 gigabits per second at a yet to be determined or specified emission wavelength or optical fiber type can be enabled by the development of more advanced VCSEL technology. One aspect of this research is to specify the VCSEL bandwidth requirement, S21, for a VCSEL operating in a transmitter at no less than 100 gigabits per second. Another related VCSEL design consideration relates to the average fiber coupled power based on typical avionics link-loss power budget and link margin requirements, i.e., 5 connectors in series and 3 dB end-of-life margin [Refs 8-9]. Another related VCSEL design consideration relates to the reliability and technology readiness. Highly accelerated life testing can be used to assess VCSEL technology readiness [Ref. 10].
It is anticipated that an uncooled VCSEL based transmitter and the corresponding receiver will include electrical equalization in order to achieve necessary performance. The VCSEL therefore must be capable of working with these electronic benefits. The desired high speed VCSEL mounted on a carrier in a fiber optic transmitter will be capable of transmitting error free digital data and video over optical fiber in a short reach (30 to 100 meters), binary non-return to zero serial link operating at no less than 100 gigabits per second. The uncooled VCSEL mounted on a carrier must perform reliably over a -40 degrees Celsius to +95 degrees Celsius temperature range, and maintain EO performance upon exposure to typical Naval air platform vibration, humidity, temperature, altitude, thermal shock, mechanical shock, and temperature cycling environments [Refs 11-14].
PHASE I: Design an uncooled high speed VCSEL and provide an approach for determining VCSEL performance parameters and testing. Demonstrate feasibility of the laser design, showing path to meeting Phase II goals. Design a high-speed VCSEL laser package prototype that is compatible with digital fiber optic transmitter interface circuitry and coupling to optical fiber. The Phase I effort will include prototype plans to be developed under Phase II.
PHASE II: Optimize the VCSEL and VCSEL package designs from Phase I. Build and test the VCSEL, and packaged VCSEL, to meet performance requirements. Characterize the VCSEL over temperature and perform highly accelerated life testing. If necessary, perform root-cause analysis and remediate VCSEL and/or packaged VCSEL failures. Deliver packaged VCSEL prototype for 100 Gb/s transmitter application.
PHASE III DUAL USE APPLICATIONS: Verify and validate the VCSEL performance in an uncooled 100 Gb/sec fiber optic transmitter that operates from -40 to +95 degrees Celsius for transition to military and commercial fiber optic transmitter manufacturing sites.
Commercial sector telecommunication systems, fiber optic networks, and data centers optical networks could benefit from the development of high speed VCSELs.
1. Larsson, A., Gustavsson, J., Westbergh, P., Haglund, E., Haglund, E., Simpanen, E., . . . and Karlsson, M. “VCSEL design and Integration for High-Capacity Optical Interconnects.” Optical Interconnects XVII, 2017, San Francisco: SPIE. https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10109/101090M/VCSEL-design-and-integration-for-high-capacity-optical-interconnects/10.1117/12.2249319.short?SSO=1
2. Szczerba, K., Lengyel, T., He, Z., Chen, J., Andrekson, P., Karlsson, M., . . . and Larsson, A. “High-Speed Optical Interconnects with 850nm VCSELS and Advanced Modulation Formats.” Vertical-Cavity Surface-Emitting Lasers XXI, 2017, San Francisco: SPIE. https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10122/101220G/High-speed-optical-interconnects-with-850nm-VCSELS-and-advanced-modulation/10.1117/12.2256992.short
3. Tatum, J., Gazula, D., Graham, L., Guenter, J., Johnson, R., & King, J. “VCSEL-Based Interconnects for Current and Future Data Centers.” Journal of Lightwave Technology, 2014, pp. 727-732. https://ieeexplore.ieee.org/document/6955704
4. Kuchta, D., Rylyakov, A., Schow, C., Proesel, J., Baks, C., Westbergh, P., . . . and Larsson, A. “A 50 Gb/s NRZ Modulated 850nm VCSEL Transmitter Operating Error Free to 90°C.” Journal of Lightwave Technology, 2013. https://vdocuments.site/a-50-gbs-nrz-modulated-850-nm-vcsel-transmitter-operating-error-free-to-90.html
5. Feng, M., Wu, C.-H. & Holonyak, N. “Oxide Confined VCSELs for High Speed Optical Interconnects.” IEEE Journal of Quantum Electronics, 2018. https://ieeexplore.ieee.org/document/8319410
6. O'Brien, C., Majewski, M. & Rakic, A. “A Critical Comparison of High-Speed VCSEL Characterization Techniques.” Journal of Lightwave Technology, 2007, pp. 597-605. https://ieeexplore.ieee.org/document/4142813
7. Deppe, D., Li, M., Yang, X. & Bayat, M. (2018). Advanced VCSEL Technology: Self-Heating and Intrinsic Modulation Response. IEEE Journal of Quantum Electronics. https://ieeexplore.ieee.org/document/8337728
8. “AS5603A Digital Fiber Optic Link Loss Budget Methodology for Aerospace Platforms.” SAE International, 2018. https://saemobilus.sae.org/content/as5603a
9. “AS5750A Loss Budget Specification for Fiber Optic Links. SAE International, 2018. https://saemobilus.sae.org/content/as5750a
10. “ARP6318 Verification of Discrete and Packaged Photonic Device Technology Readiness.” SAE international, 2018. https://saemobilus.sae.org/content/arp6318
11. “MIL-STD-810G: Environmental Engineering Considerations and Laboratory Tests.” Department of Defense, 2008.http://everyspec.com/MIL-STD/MIL-STD-0800-0899/MIL-STD-810G_12306/
12. “MIL-STD-883K: Test Method Standard Microcircuits.” Department of Defense, 2016. http://everyspec.com/MIL-STD/MIL-STD-0800-0899/MIL-STD-883K_54326/
13. “MIL-STD-38534J: General Specification for Hybrid Microcircuits.” Department of Defense, 2015. http://everyspec.com/MIL-PRF/MIL-PRF-030000-79999/MIL-PRF-38534J_52190/
14. “DO-160F: Environmental Conditions and Test Procedures for Airborne Equipment.” RTCA, 2010. https://my.rtca.org/NC__Product?id=a1B36000001IcnSEAS
KEYWORDS: Vertical Cavity Surface Emitting Laser, VCSEL: Digital Fiber Optic Transmitter, Binary Non-return to Zero Signaling, 100 Gigabits per Second, Highly Accelerated Life Testing