Method for transmitting a power unit high-intensity laser radiation

A method is proposed for transferring a unit of laser radiation power to power measuring instruments of kilowatt levels with the possibility of constant monitoring of the transmission process. A measuring optical laser power divider has been developed, which is structurally made in the form of a wedge and allows one to determine the radiation power of the beam delivered to the calibrated measuring instrument using the relatively small radiation power reflected from the enlightened surface of the front edge of the wedge. The proposed method is based on the application of the developed divider in the reference installation and provides for the implementation of three modes of operation of the installation: the mode of determining the equivalence coefficient; the mode of determining the division ratio of the optical divider; transmission mode of a power unit to measuring instruments and determination of a control parameter of an optical divider. The control of the transmission process is carried out by measuring the radiation power reflected from the rear edge of the wedge, and determining the control parameter. The conditions are given under which it is advisable to use the proposed mode for determining the division coefficient of the optical divider. A feature of the method under consideration is the possibility of operational control of the division coefficient of the optical divider, which allows real-time assessment of the accuracy of the calibration process of measuring instruments. The formula of metrological traceability of the results of power measurements to GET 28-2016 is obtained. The main components of the error in determining the radiation power supplied to the input of a calibrated measuring instrument are considered. The results of experimental studies of the method suggest that at a wavelength of 10,6 μm, the total error of power measurement, expressed as the standard deviation, does not exceed 2,0 %. The method can be used in the corresponding secondary power unit standards that receive a unit from the State Special Standard for Average Power GET 28-2016.

Microwave Photonic ICs for 25 Gb/s Optical Link Based on SiGe BiCMOS Technology

The design, simulation and experimental results of the integrated optical and electronic components for 25 Gb/s microwave photonic link based on a 0.25 µm SiGe:C BiCMOS technology process are presented. A symmetrical depletion-type Mach-Zehnder modulator (MZM) and driver amplifier are intended for electro-optical (E/O) integrated transmitters. The optical divider and combiner of MZM are designed based on the self-imaging theory and then simulated with EM software. In order to verify the correctness of the theory and material properties used in the simulation, a short test (prototype) MZM of 1.9 mm length is produced and measured. It shows an extinction ratio of 19 dB and half-wave voltage-length product of Vπ ∙ L = ~1.5 V·cm. Based on these results, the construction of the segmented modulator with several driver amplifier units is defined. The designed driver amplifier unit provides a bandwidth of more than 30 GHz, saturated output power of 6 dBm (output voltage of Vpp = 1.26 V), and matching better than −15 dB up to 35 GHz; it dissipates 170 mW of power and occupies an area of 0.4 × 0.38 mm2. The optical-electrical (O/E) receiver consists of a Ge-photodiode, transimpedance amplifier (TIA), and passive optical structures that are integrated on a single chip. The measured O/E 3 dB analog bandwidth of the integrated receiver is 22 GHz, and output matching is better than −15 dB up to 30 GHz, which makes the receiver suitable for 25 Gb/s links with intensity modulation. The receiver operates at 1.55 μm wavelength, uses 2.5 V and 3.3 V power supplies, dissipates 160 mW of power, and occupies an area of 1.46 × 0.85 mm2.

Development of components of electro-optic modulators on a semiconductor substrate for microwave photonics

The results of research and development of components of Mach-Zehnder electro-optic modulator, in particular, the Y-divider and MMI divider are presented. Technological studies were carried out and an optical divider on an InP semiconductor substrate was obtained.