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A tunable dual-mode operation with three-section distributed Bragg reflector (DBR) laser is proposed for compact and low-cost microwave generation. Stable dual-mode operation with 7 nm tuning range is demonstrated.
A controllable optical feedback system was set up to investigate the linewidth of the RF signals generated by a two-section DFB laser. A very narrow line (its width less than 100 kHz) can be detected when both sections are under the influence of optical feedback.
Optical power-spectral density of an external-cavity diode laser under coherence-selectable operation was optimized. The laser had an intracavity half-wave plate that rotates the polarization axis with regard to the grating for achieving the coherence-selectable operation. It was also shown that the resultant variation in polarization state can be readily compensated.
Relative intensity noise (RIN) characteristics of mutually injection locked distributed feedback (DFB) laser diodes is investigated. RIN around the relaxation oscillation frequency in both lasers is found to be simultaneously suppressed in the mutual locking status.
We demonstrate a novel tunable distributed feedback laser diode (DFB-LD) array with dual output of 13 dBm and 10 dBm, which can be used as full L-band light source for an optical transmitter and a local oscillator simultaneously in a coherent optical communication system.
A key feature of the whistle-geometry semiconductor ring lasers is the asymmetry between the counterpropagating modes, which might be misconstrued as a violation of the Helmholtz reciprocity principle and the time-reversal symmetry of Maxwell's equations. We confirm the unidirectionality of the proposed whistle-geometry configuration through rigorous three-dimensional finite-difference time-domain...
We investigated fundamental characteristics of a hybrid integrated photoreceiver module with a 1.5 µm-band quantum dot semiconductor optical amplifier (QD-SOA) and conventional pin-photodiode (pin-PD) as a first stage. The results indicated the photoreceiver integrated with a QD-SOA and QD-PD has the potential to be operated for signals over 100 Gb/s.
The silicon photonic wavelength tunable laser diode is a good candidate for the integrated light source of the digital coherent optical communication system .However, optical nonlinear effects easily occur due to the strong light confinement of Si photonic wire waveguides. The impact on laser operation caused by nonlinearity was discussed.
We developed a Fabry-Perot laser (FP-LD) with a Spot-Size Converter (SSC) by selective area growth and experimentally evaluated the coupling efficiency between the SSC-FP-LD and a Si waveguide with a horizontally tapered SSC. Although the addition of SSC structure in FP-LD led to the absorption loss of 0.92 dB, overall coupling efficiency was improved by 1.15 dB.
Frequency response control of semiconductor lasers is achieved by introducing a hybrid modulation scheme. A flat response with low modulation sensitivity degradation at a high-frequency region is achieved by optimizing modulation ratio and time delay between direct current modulation and intra-cavity loss modulation signals.
A thin, low-index liner layer and a high-index cover layer over a surface grating in a III–V waveguide theoretically increases the outcoupling efficiency by one or two orders of magnitude. The liner and cover layer also reduces losses between waveguide components such as distributed feedback (DBR) or grating out-coupler region.
A rate-equation theory is derived for a laser consisting of two Fabry-Pérot cavities coupled via self-imaging in a multi-mode interference reflector. Stable single-mode anti-phase operation is demonstrated and locking ranges are calculated. The shapes of output-intensity curves agree well with measured curves.
Nonlinear dynamics and high speed modulation of an optically injected microdisk laser are investigated experimentally. Small signal modulation bandwidth is increased from the free-running value of 14.4 GHz to about 38 GHz and 50 GHz under the optical injection locking and period-one oscillation states, respectively.
High power diode lasers with novel extreme-double-asymmetric epitaxial designs with increased modal confinement in the well Γ achieve high efficiency (50%) and powers (14 W) at high continuous wave heatsink temperature (75°C), attributed to the effective suppression of power saturation mechanisms. Prospects for increased performance via further increased Γ are analyzed.
High power (over 30W) and high efficiency (69%) operation 9××-nm broad area laser diodes at CW are demonstrated by diode voltage reduction and widening strip width. For the purpose of output power maximization, power saturation phenomenon is experimentally investigated associating with junction temperature and near field. Power saturation is found to be governed by not only junction temperature but...
An overview is presented of progress in studies to diagnose and address limits to peak power in high power diode lasers. Key terms in advanced structures include carrier losses in the p-side waveguide, self-heating effects in the quantum well, and longitudinal spatial hole-burning.
A short cavity distributed reflector (DR) laser with a modulation bandwidth of 55GHz was developed using the photon-photon resonance and detuned-loading effects. The importance of the chirp parameter for the speed enhancement is discussed.
The Semiconductor laser (SCL) is, arguably, the most important player in the optoelectronic field. It is hard to imagine a modern communications measurement, or a sensing system without it. It owes this distinction principally to its monolithic semiconductor character, which is responsible for a long list of crucial attributes. These include small size, efficiency, natural compatibility with electronic...
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