Frank Walters

High-performance, large area, deep ultraviolet to infrared polarizers based on 40 nm line/78 nm space nanowire grids

Large-area, 100mm in diameter, aluminum nanowire grids with 40nm line/78nm space were fabricated with full-wafer immersion interference lithography. The aluminum nanowire grids with a 59nm half-pitch work as a highly efficient optical polarizer for deep ultraviolet wavelength down to ∼250nm. In addition, an extremely high contrast from 10 000:1 to 50 000:1 was achieved across the whole visible and near-infrared wavelength range, along with good transmittance (85%–90%). The broadband large-area high-performance polarizer operating down to deep ultraviolet wavelength opens up applications including semiconductor lithography and metrology applications.

30-nm-wide aluminum nanowire grid for ultrahigh contrast and transmittance polarizers made by UV-nanoimprint lithography

Both high contrast and high transmittance are preferred for optical polarizers. To achieve high transmittance for aluminum nanowire-grid polarizers, a narrow linewidth is required. In this letter, aluminum nanowire-grid polarizers with 30-nm-wide linewidth and 200nm depth were fabricated by UV-nanoimprint lithography, which leads to ultrahigh transmittance. To achieve a high contrast, the authors fabricated the 30-nm-wide aluminum nanowire structures on both sides of the glass wafers. An extremely high contrast up to 10 000:1 was achieved, in the visible range, along with good transmittance of 83%–87% for the double-side aluminum nanowire-grid polarizers.

Large flexible nanowire grid visible polarizer made by nanoimprint lithography

117 and 150nm pitch polymer gratings were successfully fabricated on plastic substrate over large area by nanoimprint lithography. Nanowire-grid polarizers were made by depositing Al on the sidewalls of the gratings at oblique angles. The effects of grating period, grating linewidth, Al depth, and thickness were studied in detail. Excellent contrast (∼1000:1) and high transmittance (80%–90%) (without antireflection coating) at the wavelength of 500nm and above were demonstrated.

High-performance large-area ultra-broadband (UV to IR) nanowire-grid polarizers and polarizing beam-splitters

Aluminum nanowire-grid polarizers and polarizing beam splitters with a fixed pitch (i.e., period) of ~146 nm but a wide range of linewidths (from < 60 nm to 90 nm) and heights (from 150 nm to 200 nm) are studied. Immersion interference lithography, UV-nanoimprint lithography and aluminum reactive ion etching were used to fabricate the nanowire-grid polarizers. Optical performance of the nanowire-grid polarizers was characterized in a broad spectral range from UV (< 400 nm) to near infrared (> 1700 nm). The performance trade-off between transmittance/reflectance and extinction ratio is investigated in details. The developed high-performance large-area broadband nanowire-grid polarizer opens the potential for many optical applications particularly integrated optics.

58nm half-pitch plastic wire-grid polarizer by nanoimprint lithography

Plastic nanowire-grid polarizers based on small period, 58 and 75nm half-pitch, Al gratings are fabricated and studied. Al gratings are made by coating Al on the polymer grating sidewalls at oblique angles. The nanopolymer gratings on plastic film over large area are made by nanoimprint lithography. By optimizing the grating period, grating linewidth, Al coating depth, and thickness, excellent maximum transmittance (Tmax) (80%–90%) and extinction ratio (∼30dB) are achieved.

10 Gb/s transmission using an electroabsorption-modulated distributed Bragg reflector laser with integrated semiconductor optical amplifier

We demonstrate for the first time a 10 Gb/s EA-modulated wavelength-selectable DBR laser module with an integrated semiconductor optical amplifier. Transmission over 82 km of standard fiber with -3 dBm average power on 20 channels spaced by 50 GHz is achieved.

High-power, high-efficiency, and highly uniform 1.3-um uncooled InGaAsP/InP strained multiquantum-well lasers

In order to meet the increasing market needs for uncooled lasers for such applications as fiber- in-the-loop, high efficiency, high power, and highly reliable 1.3 micrometer uncooled InGaAsP/InP strained multi-quantum well Fabry-Perot lasers were fabricated with 50 mm wafer processing. Slope efficiency as high as 0.39 W/A and peak power as high as 46 mW at 85 degrees Celsius was obtained by optimizing the device structure for high temperature operation. We have also demonstrated excellent uniformity and reproducibility over 6 wafers. Reliability was also shown to be very good. More than 10,000 chips sites are available on a 50 mm wafer, and the cost is expected to be low. Because of the high performance, these lasers are expected to be used for various applications.