We introduce a low refractive index layer between the metal and the gain medium in metal-coated laser resonators and demonstrate that it can significantly reduce the dissipation losses. Analysis of a gain medium waveguide shows that for a given waveguide radius, the low index layer has an optimal thickness for which the lasing threshold gain is minimal. The waveguide analysis is used for the de...

Calculations of the longitudinal mode functions for the electric field of a compound-cavity laser show that the loss and gain coefficients are given by the Airy formula, as a function of the mode frequencies. Further, when the external cavity is longer than the gain-medium cavity, the frequency dependence of the gain is stronger than that of the loss, even when the intracavity surfaces are anti...

A Q-switched all-fiber Er-doped laser operated at a wavelength up to 1625 nm is proposed and demonstrated. self-developed, element hybridization (Al, Ge, La, P, Er in the core, Si P cladding region) glass fiber with gain extended U-band employed as medium. The compact cavity contains Bragg grating which was manufactured by means of point-by-point femtosecond inscription technique. Stable pulse ...

The field of optics has a drastic impact in the field of electronics and communication. With the rising need for higher data transfer rate, optical advancements have served this purpose. Optical amplifiers play a crucial role in the amplification of signal at regular intervals to avoid loss of data. Erbium doped fiber amplifiers (Erbium Doped Fiber Amplifier) carry out the amplification by stim...

A key challenge for silicon photonic systems is the development of compact on-chip light sources. Thulium-doped fiber and waveguide lasers have recently generated interest for their highly efficient emission around 1.8 μm, a wavelength range also of growing interest to silicon-chip based systems. Here, we report on highly compact and low-threshold thulium-doped microcavity lasers integrated wit...

We investigate theoretically the phenomenon of so-called fast light in an unconventional regime, using pulses sufficiently short that relaxation effects in a gain medium can be ignored completely. We show that previously recognized instabilities associated with coherent propagation in a gain medium can be tolerated in reaching the fast light goal of a pulse peak advance of one full peak width.

We design and demonstrate a compact, narrow-linewidth integrated laser based on low-loss silicon nitride waveguides coupled to a III-V gain chip. By using a highly confined optical mode, we simultaneously achieve compact bends and ultra-low loss. We leverage the narrowband backreflection of a high-Q microring resonator to act as a cavity output mirror, a single-mode filter, and a propagation de...

A compact digitally-controlled single-stage variable gain amplifier (VGA) is introduced, which doubles the dB-linear range through the reconfiguration, saves power by 50% while maintaining the same linearity performance compared to those of the previous design. Implemented in 0.18 mm CMOS technology, the 5-bit digitally-controlled VGA achieves dB-linear gain range of 42 dB (221 to 21 dB) with g...