Alfonso B. Piccirilli

Multiwavelength fiber ring laser source based on a delayed interferometer

A multiwavelength fiber laser source is demonstrated with a semiconductor optical amplifier as the gain medium. A delayed interferometer is incorporated in the ring cavity serving as a comb-like multichannel filter. A stable 75-wavelength simultaneous operation spaced at 40 GHz with the extinction ratio of 40 dB is achieved. By tuning the cavity loss, the center wavelength of the generated lasing waveband could be varied by as much as 20 nm.

All-optical logic xor gate at 80 gb/s using SOA-MZI-DI

All-optical xor operation has been demonstrated using a semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) and delayed interferometer (DI) at 80 Gb/s. The DI is based on a polarization maintaining loop (PML) mirror. The results show using the PML-DI in series with the SOA-MZI improves the pulse quality of the xor result

A Programmable 8-bit Optical Correlator Filter for Optical Bit Pattern Recognition

We demonstrate a compact reconfigurable 8-bit optical matching filter fabricated using 4% delta high-index-contrast silica-on-silicon waveguides. This planar lightwave circuit is based on an eighth-order tap-and-delay finite impulse response architecture. Multimode interference-based splitters/combiners along with variable optical attenuators and phase shifters allow us to tune and dynamically reconfigure all the taps and delays (filter coefficients) in the filter using a simple automated algorithm. The filter is designed to recognize 8-bit patterns in 40-Gb/s data streams and we demonstrate its working principle by successfully correlating 8-bit binary phase-shift-keyed patterns.

Colliding pulse mode-locked laser

The fabrication and performance of a colliding pulse-mode locked laser with an intracavity saturable absorber is described. The laser has a threshold current of 65 mA and differential efficiency of 0.04 mW/mA when coupled into a single-mode fiber. Mode-locked pulses with /spl sim/1 ps pulse width at /spl sim/10 GHz has been obtained.

All-Optical Byte Recognition for 40-Gb/s Phase-Shift-Keyed Transmission Using a Planar-Lightwave-Circuit Passive Correlator

We demonstrate all-optical recognition of a byte pattern embedded in phase-shift-keyed data streaming at 40 Gb/s. We use matched filtering to generate an autocorrelation pulse indicating the pattern matching. Matched filtering is implemented using a reconfigurable silica planar-lightwave-circuit optical delay-line filter. We show excellent discrimination against spurious patterns consistent with the theoretical predictions.

Four wave mixing in semiconductor optical amplifier

We have performed four wave mixing (FWM) measurements on a 2-section semiconductor optical amplifier(SOA) using CW and pulsed pump and probe beams. The FWM efficiency depends on the input pump power, the gain of the 2-section SOA and the wavelength separation between the pump and probe beams. A -19.1 dBm FWM signal power from the amplifier is achieved when the wavelength difference between the pump and probe beams is 2.5 nm. The pulse amplitude and pulse width of the FWM signal under the condition when the FWM signal is generated using pulsed pump and probe beams has been measured and analyzed. The results of the analysis are in agreement with the experimental data.

Space certification and qualification programs for laser diode modules on the NASA ICESat-2 Mission

A laser diode module (LDM) space certification and qualification program was developed for NASA’s Ice, Cloud and Land Elevation Satellite-2, ICESat-2 mission. The ICESat-2 laser transmitter is a high performance diode-pumped solid state laser that requires high reliability, high efficiency and high brightness fiber coupled LDMs, capable of supporting a 27,000 hour mission life. The test centric LDM space certification and qualification programs consisted of several key phases including a technology plausibility study, laser diode and LDM pedigree reviews, environmental acceptance and qualification testing, and extensive life testing. The intent of the plausibility study was to analytically and experimentally demonstrate that a commercial-off-the-shelf (COTS) LDM design was capable of being space-certified. A pedigree review of the laser diode population was conducted to reject out-of-family laser diodes from the population. The laser diode pedigree review was a statistical analysis of several laser diode performance metrics (efficiency, operating current, etc.) with outliers being rejected. All LDMs underwent environmental acceptance testing including vibration, thermal cycling and an extended burn-in. The primary purpose of the acceptance testing was to highlight internal workmanship issues. The pedigree review of the acceptance tested LDMs was conducted to reject out-of-family LDMs in statistical analysis of several performance metrics (operating current, coupling efficiency, etc.). A sub-set of the flight-certified LDMs will be exposed to environmental qualification testing and will subsequently be tested to failure to determine the LDM capability. Multiple LDMs are being life tested under flight-like conditions and show no signs of degradation with run times of 22,000 hours, which is over 80% of the mission life. Details of the LDMs space certification and qualification programs are presented.

All-optical logic XOR gate at 80 Gb/s using SOA-MZI-DI

All-optical xor operation has been demonstrated using a semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) and delayed interferometer (DI) at 80 Gb/s. The DI is based on a polarization maintaining loop (PML) mirror. The results show using the PML-DI in series with the SOA-MZI improves the pulse quality of the xor result

Failure mode analysis of high-power laser diodes

In this paper, we present the results of a preliminary investigation on the reliability of high power optical diodes. Commercially available 970 nm optical diodes were subjected to various levels of stress, including: operating current, optical power and operating temperature. Optical diodes that failed during testing were subsequently analyzed using a variety of techniques, including: optical microscopy, scanning electron microscopy, eletroluminescence, and near-field profiling. It has been observed that the major cause of optical failure can be attributed to damage on the emitting facet of the optical diodes. Preliminary evidence suggests that facet damage is a result of catastrophic optical damage.

Preliminary results of testing a space-grade laser transmitter for optical communications

Pulsed fiber based laser transmitters suitable for optical communications in both near Earth and deep space scenarios are being developed in partnership between JPL and industry. As a precursor to a full space qualification process, commercial components were integrated into a polarization maintaining 1550 nm master oscillator laser as part of a master oscillator power amplifier (MOPA) laser transmitter designed to support pulse position modulation and operation in the vacuum environment. This optically pre-amplified seed laser generated sub-ns pulses at up to 100 MHz with high extinction ratio over variable duty cycle. Test results in both ambient and under vacuum conditions will be reported for this system including a preliminary life-test with over 5000 hours under high vacuum at temperatures ranging from 0 to 40 °C.