Jeffrey E. Ungar

Advances in high-brightness semiconductor lasers

We present recent advances in high power semiconductor laser bars and arrays at near infrared and eye-safe wavelengths. We report on increased spectral brightness with internal gratings to narrow and stabilize the spectrum and increased spatial brightness in multimode and single mode devices. These devices have the potential to dramatically improve diode pumped systems and enable new direct diode applications.

High-power semiconductor lasers at eye-safe wavelengths

InP based diode lasers are required to realize the next generation of eyesafe applications, including direct rangefinding and HEL weapons systems. We report on the progress of high power eyesafe single spatial and longitudinal mode 1550nm MOPA devices, where we have achieved peak powers in excess of 10W with 50ns pulse widths. A conceptual model based on our recent MOPA results show the path towards scaling to high powers based on spatial beam combination with operating conditions suitable for direct rangefinding applications. We also report on the progress towards high power 14xx and 15xx nm pump lasers for eyesafe HEL systems.

High-brightness semiconductor lasers

We present recent advances in high power semiconductor lasers including increased spectral brightness using on-chip internal gratings and increased spatial brightness at wavelengths from the near infrared to the eye-safe regime.

A GPU-based full-chip inverse lithography solution for random patterns

An inverse lithography solution based on optimization is presented. The optimization approach, in effect, operates as an inverse lithography tool, based on modeling and simulation of the manufacturing process. Given the associated computational requirements, the proposed solution intentionally uses graphic processors (GPUs) as well as CPUs as computation hardware. Due to the approach we employed, the results are optimized towards manufacturability and process window maximization.

Advances in semiconductor laser bars and arrays

Advances in high power semiconductor lasers such as increased spectral brightness, increased spatial brightness, and reduced cost architectures at wavelengths from the near infrared to the eye-safe regime have the potential to dramatically improve diode pumped systems and enable new direct diode applications. Data are presented which demonstrate both edge emitter devices and high power surface emitting 2-dimensional arrays with internal gratings to narrow and stabilize the spectrum. Diodes with multimode high spatial brightness and high power single mode performance in the 808 and 976nm regime are described, and advances in high power arrays at eye-safe wavelengths are presented.

High-spectral brightness pump sources for diode-pumped solid state lasers

The development of on-chip grating stabilized semiconductor lasers for diode pumped solid state lasers is discussed. The diode lasers, specifically at wavelengths of 808nm, 976nm, and 1532nm are stabilized via internal gratings to yield a typical center wavelength tolerance of ± 1nm, FWHM of < 1-2nm, and a temperature tuning coefficient of < 0.09 nm/°C. We also report on the CW and QCW operation of conduction cooled bars, stacks, and fiber coupled modules. Simulations show that on-chip stabilized pump sources yield performance improvements over standard pumping schemes. A comparison in laser performance is shown for typical DPSS configuration.

Ultracompact visible R-G-B lasers for defense applications

Compact, efficient visible lasers are important for heads up displays, pointing and illumination, undersea communications, and less than lethal threat detection. We report on high power red, green, and blue lasers with output powers above 3 watts and efficiencies greater than 20%, 15%, and 5% respectively.

Reliability of single-mode and multi-mode high-power semiconductor lasers at eye-safe wavelengths

High power semiconductor lasers with wavelengths in the eye-safer region have application to a variety of defense, medical and industrial applications. We report on the reliability of high power multimode and single mode InGaAsP/InP diode lasers with wavelengths in the range 1320 to 1550 nm in a variety of configurations, including single-chip, conduction-cooled arrays, arrays incorporating internal diffraction gratings, master-oscillator power amplifiers, and fiber-coupled modules of the above. In all cases we show very low rates of degradation in optical power and the absence of sudden failure from catastrophic optical damage or from laser-package interactions.

Developing high brightness semiconductor lasers for homeland security and defense applications

We present recent advances in high brightness, high power semiconductor lasers and their applications in homeland security and defense including countermeasures, bio-chemical agent detection, rangefinding, targeting, and directed energy weapons.

High Brightness Semiconductor Lasers with Internal Gratings

We present recent advances in high power semiconductor lasers including increased spectral brightness using on-chip internal gratings, increased spatial brightness, and reduced cost architectures at wavelengths from the near infrared to the eye-safe regime.