This paper deals with the theory and device applications of periodic thin-film waveguides. Topics treated include mode solutions, optical filters, distributed feedback lasers (DFB), distributed Bragg reflector (DBR) lasers, grating couplers, and phase matching in nonlinear interactions.

/pdf/periodic-structures-for-integrated-optics-inegvy8lro.pdf

Periodic structures for integrated optics

Recent progress in the dynamic single-mode (DSM) semiconductor lasers in the wavelength of 1.5-1.6\mu m are reviewed and the basic principle of DSM operation is given. Study of the DSM laser is originated for application to the wide-band optical-fiber communication in the lowest loss wavelength region of 1.5 to 1.65 μm. A DSM laser consists of a mode-selective resonator and a transverse-mode-controlled waveguide, such as the narrow-striped distributed-Bragg-reflector (DBR) laser, so as to maintain a fixed axial mode under the rapid direct modulation. The technology of monolithic integration for optical circuits is applied to realize some of DSM lasers. Structures, static and dynamic characteristics of lasing wavelength, output power, and reliability of the art DSM lasers are reviewed. The dynamic Spectral width of 0.3 nm, the output power of a few milliwatts, and the reliability over a few thousand hours are reported for experimental DSM lasers.

Dynamic single-mode semiconductor lasers with a distributed reflector

A method of forming a semiconductor device includes the following steps: providing a plurality of semiconductor layers; providing means for coupling signals to and/or from layers of the device; providing a quantum well disposed between adjacent layers of the device; and providing a layer of quantum dots disposed in one of the adjacent layers, and spaced from the quantum well, whereby carriers can tunnel in either direction between the quantum well and the quantum dots.

Semiconductor devices and methods

A frequency multiplexing light source is realized by monolithically integrating GaAs‐GaAlAs distributed‐feedback diode lasers with different grating periods and passive waveguides on a GaAs substrate. The lasers with wavelength separation of ∼20 A are modulated independently, and the output beams are obtained from a common launching waveguide.

Frequency multiplexing light source with monolithically integrated distributed‐feedback diode lasers

Monolithic two‐section GaInAsP/InP lasers are shown to operate in a single longitudinal mode under high‐speed pulsed current modulation. The length of the emitted monomode light pulses is less than 500 ps. The suppression of secondary modes is described in a rate equation model that is generally useful for a variety of coupled‐cavity configurations. It is found that 10% increase in cavity loss for the unwanted modes is sufficient to provide 17 dB suppression.

Single‐mode operation of coupled‐cavity GaInAsP/InP semiconductor lasers

The lasing characteristics of separate-confinement-heterostructure (SCH-structure) distributed-feedback (DFB) diode lasers are examined theoretically and experimentally. Wave propagation in five-layer SCH waveguides is analyzed to estimate such parameters as the lasing wavelength, coupling constant, and external quantum efficiency. Spectral and modal behavior are studied in the experiment and compared with the theoretical predictions. Diodes are shown to lase in a single longitudinal mode with a definite polarization. Spectral width is about 300 MHz just above the threshold, and becomes wider with increased excitation level. An output power of 40 mW with an external quantum efficiency of 5 percent is obtained under CW operation.

J. Umeda

Papers

Lasing characteristics of distributed-feedback GaAs-GaAlAs diode lasers with separate optical and carrier confinement