Stefan Meister

Trends in stimulated Brillouin scattering and optical phase conjugation

An overview on current trends in stimulated Brillouin scattering and optical phase conjugation is given. This report is based on the results of the “Second International Workshop on stimulated Brillouin scattering and phase conjugation” held in Potsdam/Germany in September 2007. The properties of stimulated Brillouin scattering are presented for the compensation of phase distortions in combination with novel laser technology like ceramics materials but also for e.g., phase stabilization, beam combination, and slow light. Photorefractive nonlinear mirrors and resonant refractive index gratings are addressed as phase conjugating mirrors in addition.

Results of a round-robin experiment in multiple-pulse LIDT measurement with ultrashort pulses

For the development of standard measurement procedures in optics characterization, comparative measurement campaigns (Round-robin experiments) are indispensable. Within the framework of the CHOCLAB project in the mid-90s, several international Round-robins were successfully performed qualifying procedures for e. g. 1 on 1-LIDT, laser-calorimetry and total scattering. During the recent years, the demand for single pulse damage investigations has been overtaken by the more practically relevant S on 1-LIDT. In contrast to the industrial needs, the comparability of the multiple-pulse LIDT has not been proven by Round-robin experiments up to now. As a consequence of the current research activities on the interaction of ultra-short pulses with matter as well as industrial applications, numerous fs-laser systems become available in universities and research institutes. Furthermore, special problems for damage testing may be expected because of the intrinsic effects connected with the interaction of ultrashort pulses with optical materials. Therefore, a Round-robin experiment on S on 1-damage testing utilizing fs-pulses was conducted within the framework of the EUREKA-project CHOCLAB II. For this experiment, seven parties investigated different types of mirrors and windows. Most of the partners were guided by the International Standard ISO 11254-2, but one partner employed his own damage testing technique. In this presentation, the results of this comparative experiment are compiled demonstrating the problems induced by special effects of damage testing in the ultra-short pulse regime.

Photonic crystal microcavities in SOI waveguides produced in a CMOS environment

We have investigated microcavities in Silicon-on-Insolator (SOI) waveguides. The rectangular waveguides with 500 nm width are fabricated in the 220 nm silicon device layer. The microcavities are formed by one-dimensional photonic crystals in Fabry-Perot structure directly written in the waveguides. The SOI photonic structures are produced in a CMOS environment using 248 nm DUV lithography, where the waveguides as well as the photonic crystals are created in the same step using a single mask. In order to achieve a desired spectral shape of the filter function capable for several applications, a number of different cavities were investigated, e.g. single cavities of first and higher order as well as multi-cavity filters. The experimental results are compared with simulations of photonic crystal microcavities in strip waveguides. The spectral transmission function of such filters dependent on the design parameters are calculated by an analysis based on Finite-Difference-Time-Domain (FDTD) method.

Novel Ring Resonator Combining Strong Field Confinement With High Optical Quality Factor

Slot waveguide ring resonators appear promising candidates for several applications in silicon photonics. Strong field confinement, high device tunability, and low power consumption are beneficial properties compared with strip waveguides. Slot waveguide ring resonators suffer, however, from rather low optical quality factors due to optical losses. This letter proposes and experimentally demonstrates a novel concept based on a partially slotted ring and a strip-to-slot mode converter. An exceptional high quality factor of ~105 has been measured.

Operation of a Raman laser in bulk silicon

A Raman laser based on a bulk silicon single crystal with 1.127 μm emission wavelength is demonstrated. The Si crystal with 30 mm length was placed into an external cavity and pumped by a Q-switched Nd:YAG master oscillator power amplifier system. Strong defocusing of the pump and Raman laser beam by free carriers was compensated by an intracavity lens. Raman laser operation with a pulse duration of 2.5 ns was identified by a Raman laser threshold significantly lower than the single-pass stimulated Raman-scattering threshold. Linear absorption losses of the 1.06415 μm pump radiation are strongly reduced by cooling the Si crystal to a temperature of 10 K.

25 Gb/s Silicon Photonics Interconnect Using a Transmitter Based on a Node-Matched-Diode Modulator

In this article a nonreturn-to-zero data transmission of 25 Gb/s between silicon photonic transmitter and receiver units is demonstrated, where the transmitter is based on a silicon optical Fabry-Pérot modulator with a node-matched-diode geometry. This modulator type has a footprint of less than 100 μm2. On the receiver side, an integrated Ge-photo detector has been used. Mask tests according to the 100G ER4 standard have been performed and yielded error free data transmission.

High-Speed Fabry–Pérot Optical Modulator in Silicon With 3-μm Diode

A silicon optical modulator using a novel node-matched-diode geometry inside a Fabry-Pérot nanowaveguide resonator is presented. The diode length is only 3 μm. An analysis of the dynamic spectral transmission behavior is given. Non-return-to-zero data transmission of 10 Gb/s is demonstrated.

Compact electrically tunable delay generator on silicon

Feasibility of a tunable delay of optical data streams is proved by experimentally validating a hybrid fiber/integrated realization. Ultimate design can provide delays of more than 200 ps in an area of about 0.4 mm2.

Silicon photonics for 100 Gbit/s intra-data center optical interconnects

We report on an ultra-compact co-integrated transmitter and receiver in SiGe BiCMOS technology for short reach optical interconnects. A fully integrated EPIC transceiver chip on silicon photonics technology is described. The chip integrates all photonic and electronic devices for an electro-optic transceiver and has been designed to be testable on wafer-scale. A node-matched diode modulator based on carrier injection is a key building block in the chip design. Its operation performance is presented with respect to insertion loss, signal-to-noise-ratio and power consumption at a 25.78125 Gbit/s in NRZ operation. A novel SiGe based photodetector exhibits a -3 dB bandwidth of up to 70 GHz and a responsivity of >1 A/W. Details are given about the process technology of co-integration of photonic and electronic integrated circuits using both silicon-on-insulator and bulk silicon. The implemented co-integration process requires only few additional process steps, leading to only a slight increase in complexity compared to conventional CMOS and BiCMOS baselines.

Partially slotted silicon ring resonator covered with electro-optical polymer

In this work, we present for the first time a partially slotted silicon ring resonator (PSRR) covered with an electro-optical polymer (Poly[(methyl methacrylate)-co-(Disperse Red 1 acrylate)]). The PSRR takes advantage of both a highly efficient vertical slot waveguide based phase shifter and a low loss strip waveguide in a single ring. The device is realized on 200 mm silicon-on-insulator wafers using 248 nm DUV lithography and covered with the electro-optic polymer in a post process. This silicon-organic hybrid ring resonator has a small footprint, high optical quality factor, and high DC device tunability. A quality factor of up to 105 and a DC device tunability of about 700 pm/V is experimentally demonstrated in the wavelength range of 1540 nm to 1590 nm. Further, we compare our results with state-of-the-art silicon-organic hybrid devices by determining the poling efficiency. It is demonstrated that the active PSRR is a promising candidate for efficient optical switches and tunable filters.