5,503 research outputs found
Experimental investigation of the impact of optical injection on vital parameters of a gain-switched pulse source
An analysis of optical injection on a gain-switched distributed feedback (DFB) laser and its impact on pulse parameters that influence the performance of the pulse source in high-speed optical communication systems is presented in this paper. A range of 10 GHz in detuning and 5 dB in injected power has been experimentally identified to attain pulses, from an optically injected gain-switched DFB laser, with durations below 10 ps and pedestal suppression higher than 35 dB. These pulse features are associated with a side mode suppression ratio of about 30 dB and a timing jitter of less than 1 ps. This demonstrates the feasibility of using optical injection in conjunction with appropriate pulse compression schemes for developing an optimized and cost-efficient pulse source, based on a gain-switched DFB laser, for high-speed photonic systems
Fiber Laser for Phase-Sensitive Optical Time-Domain Reflectometry
We have designed a new fiber laser configuration with an injection-locked DFB laser applicable for phase-sensitive optical time-domain reflectometry. A low-loss fiber optical ring resonator (FORR) is used as a high finesse filter for the self-injection locking of the DFB (IL-DFB) laser. By varying the FORR fidelity, we have compared the DFB laser locking with FORR operating in the under-coupled, critically coupled, and over-coupled regimes. The critical coupling provides better frequency locking and superior narrowing of the laser linewidth. We have demonstrated that the locked DFB laser generates a single-frequency radiation with a linewidth less than 2.5Â kHz if the FORR operates in the critically coupled regime. We have employed new IL-DFB laser configuration operating in the critical coupling regime for detection and localization of the perturbations in phase-sensitive OTDR system. The locked DFB laser with a narrow linewidth provides reliable long-distance monitoring of the perturbations measured through the moving differential processing algorithm. The IL-DFB laser delivers accurate localization of the vibrations with a frequency as low as ~50Â Hz at a distance of 9270Â m providing the same signal-to-noise ratio that is achievable with an expensive ultra-narrow linewidth OEwaves laser (OE4020â155000-PA-00)
Room temperature InGaAs/InP distributed feedback laser directly grown on silicon
We report an optically pumped room-temperature O-band DFB laser, based on the buffer-less epitaxial growth of high quality InGaAs/InP waveguides directly on silicon wafer
Laterally-Coupled Dual-Grating Distributed Feedback Lasers for Generating Mode-Beat Terahertz Signals
We present a laterally-coupled AlGaInAs/InP DFB laser emitting two longitudinal modes simultaneously within the same cavity and integrated with EAM. A stable 0.82 THz beating signal was observed over a wide range of bias parameters
155-ÎŒm distributed feedback laser monolithically integrated with amplifier array
We present a laterally coupled 1.55-ÎŒm distributed feedback laser monolithically integrated with multistage multimode interferences and semiconductor optical amplifiers, using low-bias currents and providing an output power of âŒ100ââmW with a quasi-single spatial-mode far-field pattern and low divergence angle of 3.5° in the horizontal direction. The fabrication techniques are based on side-wall gratings and quantum-well intermixing and offer a simple, flexible, and low cost alternative to conventional methods
Monolithic quantum-dot distributed feedback laser array on silicon
Electrically-pumped lasers directly grown on silicon are key devices
interfacing silicon microelectronics and photonics. We report here, for the
first time, an electrically-pumped, room-temperature, continuous-wave (CW) and
single-mode distributed feedback (DFB) laser array fabricated in InAs/GaAs
quantum-dot (QD) gain material epitaxially grown on silicon. CW threshold
currents as low as 12 mA and single-mode side mode suppression ratios (SMSRs)
as high as 50 dB have been achieved from individual devices in the array. The
laser array, compatible with state-of-the-art coarse wavelength division
multiplexing (CWDM) systems, has a well-aligned channel spacing of 20 0.2 nm
and exhibits a record wavelength coverage range of 100 nm, the full span of the
O-band. These results indicate that, for the first time, the performance of
lasers epitaxially grown on silicon is elevated to a point approaching
real-world CWDM applications, demonstrating the great potential of this
technology
Room Temperature InP DFB Laser Array Directly Grown on (001) Silicon
Fully exploiting the silicon photonics platform requires a fundamentally new
approach to realize high-performance laser sources that can be integrated
directly using wafer-scale fabrication methods. Direct band gap III-V
semiconductors allow efficient light generation but the large mismatch in
lattice constant, thermal expansion and crystal polarity makes their epitaxial
growth directly on silicon extremely complex. Here, using a selective area
growth technique in confined regions, we surpass this fundamental limit and
demonstrate an optically pumped InP-based distributed feedback (DFB) laser
array grown on (001)-Silicon operating at room temperature and suitable for
wavelength-division-multiplexing applications. The novel epitaxial technology
suppresses threading dislocations and anti-phase boundaries to a less than 20nm
thick layer not affecting the device performance. Using an in-plane laser
cavity defined by standard top-down lithographic patterning together with a
high yield and high uniformity provides scalability and a straightforward path
towards cost-effective co-integration with photonic circuits and III-V FINFET
logic
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