Central Emission Wavelength Research Articles

Widely Tunable GaSb-Based External Cavity Diode Laser Emitting Around 2.3$mu$m

We report on a widely tunable external cavity GaSb-based diode laser (ECL) in Littrow-configuration. The low (44deg full-width at half-maximum) fast axis beam divergence of the quantum-well diode laser employed allowed an efficient coupling to the external cavity, which resulted in a wide tuning range of 177 nm around the central emission wavelength of 2.30 mum. The maximum output power of the fiber coupled ECL system varied only moderately between 16.5 mW at 2.23 mum and 9 mW at the long-wavelength limit at 2.39 mum

High quality AlGaInP epilayers grown by MOCVD using TBP for red lasers

AlGaInP epilayers of different Al compositions and AlGaInP/GaInP multiple quantum well (MQW) structures have been grown by metalorganic chemical vapor deposition using tertiarybutylphosphine (TBP) as phosphorus precursor. Low-temperature photoluminescence (PL) measurements have been performed to evaluate the quality of the materials. The line widths of the PL spectra of AlGaInP epilayers grown with TBP are comparable to those grown using PH 3, suggesting the high quality of AlGaInP grown by TBP. Finally, AlGaInP MQW red laser structures have been grown, and for the first time the electrically pumped AlGaInP red lasers grown by TBP have been reported with the central emission wavelength of 645 nm, indicating that TBP can be used to grow high quality AlGaInP epilayers and AlGaInP-based red lasers in parallel with the widely used highly toxic gas source PH 3.

Insight into planar microcavity emission as a function of numerical aperture

This paper develops a semi-empirical model to investigate the spectral properties of planar microcavities as a function of the observation numerical aperture (NA). The development of the model clearly highlights the fundamental principles of planar microcavity emission which are therefore applicable to resonant cavity light emitting diode (RCLED) structures in general. In the present work, we clearly identify features of planar microcavity emission that are often overlooked in the literature, namely, an increase in line width with NA (by a factor of 3 in the present samples) and the peak shift of the central emission wavelength as a function of NA and detuning. The analysis identifies an intrinsic shift in peak emission wavelength over the observation NA which is attributed to a planar microcavity's preference for off-axis emission. It is clear the spectral properties of planar microcavities are explicitly dependent on NA highlighting the importance of well-defined coupling optics in the design of optical systems incorporating RCLEDs.

Single‐mode fiber transmission using edge‐emitting led for broadband subscriber loops

AbstractThe edge‐emitting LED, which is less expensive and more reliable than the laser diode, is studied for use in the broadband subscriber loop in combination with a single‐mode fiber. In comparison to the conventional surface‐emitting LED, the present device has a better efficiency in coupling with a single‐mode fiber and has a narrower emission spectrum. In this paper, a method of simple time domain calculation is proposed for the S/N ratio taking into account the wavelength dependence on the dispersion and loss of the fiber, the emission spectrum profile of the edge‐emitting LED, and the pulse response speed. The validity of the computation method and the high‐speed modulation characteristics of the edge‐emitting LED are confirmed through the optical transmission experiment of 600 Mbit/s and 20 km with a simple waveform compensation circuit. Further, the temperature characteristic of the edge‐emitting LED is studied since it is important in the application to a practical system. A method for temperature compensation is investigated. Finally, based on these studies, the maximum transmission distance is studied in which the temperature variations of the optical output, center emission wavelength and the spectral width as well as the device fluctuation are considered. It is shown that the present edge‐emitting LED is capable of an application to broadband ISDN and optical CATV subscriber loops.

Active mode-locking of an external cavity GaInAsP laser incorporating a fibre-grating reflector

Active mode-locking of a GaInAsP semiconductor diode amplifier, coupled to an external cavity incorporating an optical fibre grating as a bandwidth limiting and wavelength selective mirror, is reported. The grating defined the central emission wavelength to the 1.53μm region where modelocked pulses having durations ofless than 10 ps were generated at a repetition rate of 648 MHz.