The nonlinear dynamic behavior of a direct frequency-modulated diode laser with strong optical feedback is examined and compared to a laser diode subject to electro-optically modulated, strong optical feedback. Direct modulation is achieved by sinusoidal modulation of the diode laser injection current. Electro-optic modulation is achieved by applying a sinusoidal voltage to an intracavity phase...

In this work we have designed a Mach Zehnder interferometer (MZI) for electro optic modulator at telecommunication wavelength using GaN on Sapphire. The knowledge of GaN sample optical properties were also investigated, resulting refractive index for the GaN layers were found to be nTE=2.279±0.001 and nTM = 2.316±0.001 and good temperatur stability. Optimization of the structure parameters and ...

We demonstrate a polarizer-free electro-optical switch using dye-doped liquid crystal (LC) gels. The mechanism of dye-doped LC gels mainly involves the combination of polymer scattering and dye absorption. However, the domain size of polymer networks, dye concentration, LC concentration, and fabrication process can all affect the phase separation process and thus result in dye-doped LC gels wit...

With an optically active langasite (LGS) crystal as the electro-optic Q-switch, we demonstrate an efficient Q-switched laser with a repetition rate of 200 kHz. Based on the theoretical analysis of the interaction between optical activity and electro-optic property, the optical activity of the crystal has no influence on the birefringence during Q-switching if the quarter wave plate used was rot...

Introduction: High-speed and high-performance optical switches are vital for optical communication networks and optical signal-processing systems. Among these, optical switches based on the electro-optic (EO) effect are promising for applications that require high-speed switching, such as: optical burst switching or optical packet switching. Mach–Zehnder interferometer (MZI) switches and direct...

A 2×2 high contrast ratio optical switch composed of holographic optical switching elements is presented. This switch consists of two electro-optic halfwave plates, four layers of holographic gratings, two dielectric substrates, and one spacer. The contrast ratio can be higher than 54 dB. The contrast ratio improvement of this device is the same as a dilated optical switch. Key-words: Holograph...

Since the emergence of optical fiber communications, lithium niobate (LN) has been the material of choice for electro-optic modulators, featuring high data bandwidth and excellent signal fidelity. Conventional LN modulators however are bulky, expensive and power hungry, and cannot meet the growing demand in modern optical data links. Chip-scale, highly integrated, LN modulators could offer solu...

Dual-comb interferometry is a measurement technique that uses two laser frequency combs to retrieve complex spectra in a line-by-line basis. This technique can be implemented with electro-optic frequency combs, offering intrinsic mutual coherence, high acquisition speed and flexible repetition-rate operation. A challenge with the operation of this kind of frequency comb in dual-comb interferome...

In this review paper we showcase recent activities on silicon photonics science and technology research in Hong Kong regarding two important topical areas — microresonator devices and optical nonlinearities. Our work on silicon microresonator filters, switches and modulators have shown promise for the nascent development of on-chip optoelectronic signal processing systems, while our studies on ...

The electro-optical properties of organic and polymeric materials are regarded as holding potential for developments in charge storage, analytical sensors, electroluminescent devices, optical data processing and integrated optics. For example, nowadays it is clear that sensor sensitivities and specificity can be increased by using redox polymers [1] or that the parameters characterizing the rel...