Multi-facility comparison of InGaAs trap detector responsivity for optical fiber power

Optical fiber power is an important physical quantity for optical fiber communication measurement. Currently, the absolute optical fiber power is traceable to absolute radiometer, such as electrically calibrated radiometer, and cryogenic radiometer. For optical fiber power transfer, the primary standard of NIM is the cryogenic radiometer that has an uncertainty of 2 parts in 104. Because most cryogenic radiometers are designed to be used with collimated beams rather than divergent beams from an optical fiber; therefore transfer standards should be well designed for optical power measurement using the beam geometry correction. We designed a trap detector using for optical fiber power transfer. One can omit the beam geometry correction from an optical fiber using his design. We present a fiber power measurement using a planar detector compared with this trap detector, which are traceable to the primary standard (cryogenic radiometer). The difference between the comparison shows that the trap detector is suitable for absolute fiber power measurement, meanwhile optical fiber power transfer using planar detectors should be corrected when transferred from cryogenic radiometer.

A comparison of different transfer standard optical fiber power detectors is present. Traceable to cryogenic radiometer, these planar, focus-planar and trap detectors have different characteristics during the optical fiber power values transfer because of the different input angles or fiber connectors. For different types of fibers and fiber connectors, a new trap detector is capable for the optical fiber power measurement, which has very little sensitivity for a variety of input conditions. Comparison of fiber power measurement using a planar and a trap detector is present by employing a three-lens method. A good agreement between the two types of detectors shows the feasibility of fiber power transfer using planar detectors.

We will present our current efforts on single photon quantum metrology using high-efficiency superconducting detectors and high-efficiency single-photon sources based on spontaneous parametric downconversion. Optical power measurements based on single photon counting could establish a quantum standard for optical power calibration in the future. At NIST we are pursuing the development of single photon sources and single photon detectors for metrology, quantum and classical applications. As part of these efforts, we are pursuing the establishment of a measurement service for the calibration of single photon detectors. We present how our calibration is tied to the calibration of our transfer standard optical fiber power meters. Using the beamsplitter method, we have implemented a fiber-coupled and free-space measurement system. Also, we have developed testbeds and measurement protocols for the characterization of single photon sources and single photon detectors. We will review several methods, which allow for the characterization of the spatial and spectral degree of freedom in spontaneous parametric downconversion.

A calorimeter for optical fiber power measurement is developed. It has a compensative absorber to stabilize environmental disturbance, and two types of adapters for optical fibers and light beams. The uncertainty in measurements of 1-mW and 10- mu W optical fiber power was evaluated as +or-0.18% and +or-0.45% respectively, expressed as two standard deviations. The calibration uncertainty of an optical fiber power meter using the calorimeter as a primary standard is reduced by more than one half compared to that of the conventional method using a laser beam calorimeter and photodiode-type transfer standard. >

An optically powered sensor for measuring pressure which linked by optical fiber is developed in a new scheme. Its pulse position modulation (PPM) optical signal and optical supply power for electronics in probe are transmitted to and fro via a single optical fiber. The optical power is carried by a laser diode (LD) source with 1300 nm wavelength and the sensing data are carried by LED 850 nm source. The remote probe uses all CMOS chips and particular modulations (PPM and PWM). Its electrical consumption including signal manipulation and LED driven current from optical conversion is less than 100 (mu) W. The laser diode supplies 5 mW of optical power into the fiber. An advanced photodetector converts sufficiently the section of this power into electrical power to drive the whole probe operation. The optically powered distance gets up to 500 m. The novel sensor combines advanced optical fiber and electronics technology into a system. It continuously measures pressure in real time. Because of using the principle of ratio measurement between mesurand and reference signals, as well as light feedback for light source stability, the system is available with high reliability, outstanding accuracy, and repeatability.

This study seeks to simulate the amplification of the optical fiber power by the generation of higher order solitons. This was achieved by solving an extended form of the nonlinear Schrödinger equation (NLSE) using the split step Fourier method (SSFM) with Gaussian functionals having multiple peaks as initial conditions to simulate the generation of higher order solitons in the optical fiber. Some key fiber parameters such as the coefficients of loss α, group velocity dispersion β and nonlinearity γ were varied and the respective effects on the optical fiber and soliton power were then observed using spatial plots, 3-D contour plots and image color maps. Results obtained showed that in all soliton orders, higher order solitons were created when β was increased from 0.05 to 0.1 fs/nm.km. This shows a broadening of the soliton to create higher order solitons when dispersion is managed within that range which results in a boost in the peak soliton power amplified from 4.5309 W to 14.9508 W and then to 15.0828W as the soliton order was increased from 1st – 2nd – 3rd order respectively using Gaussian functionals. The extra power gained is as a result of the fact that a newly created soliton takes its energy from the radiation present in the dispersed soliton even though the optical power attenuates. It was also observed that, increasing the coefficients α, β and γ from 0.1 – 1.0 results in a continuous attenuation of the optical fiber power leading to the propagation of radiation (noisy signal) in the optical fiber which scatters and exponentially decays after a short distance along the length of the optical fiber.

We have developed and evaluated a transfer standard for the calibration of optical fiber power meters over the wavelength range from 750–1800 nm. The transfer standard is an optical-trap detector consisting of two germanium (Ge) photodiodes, and a spherical mirror. The photodiodes and mirror are contained in a package that is thermally stable and accepts a variety of optical fiber connectors. Spatial uniformity measurements indicate that the variation of detector response as a function of beam position is less than ±0.15%. Comparison of the absolute responsivity for three different input conditions indicates that the detector responsivity is nearly the same for collimated beams transmitted through air, as for diverging input from an optical fiber. Small measurement-result differences between collimated and diverging inputs still remain and are discussed briefly.

An optical fiber power delivery system is presented. As an application, a sensor module is optically powered, constituting an electrically isolated system, since it also sends the measured data through an optical fiber.

There is clear difference in each fiber-optic link's power output, in the large scale optically controlled phased array antenna. In order to realize the optical power balance and control between the various channels, the equilibrium or control power of each optical signal needs to be considered, and it will reduce the optical beam forming network generat- ed side-lobe beam, which results in the performance improvement of the system. In this paper, the methods of optical power equalization and control is proposed, which is used in the forming network of the optical beam. The method can re- alize the optical power's equalization and control of each optical signal. In the end of this paper, the verification and re- sults are provided. Some researchers advance a new theory very early, which is using optical fiber as delay medium in the signal processing of microwave and millimeter waves. The tech- nology of Optical True Time-Delay is appeared, and it is the earliest application, which is used in microwave photonic filter and optically controlled phased array antenna. The technological idea of OCPAA, which is based on OTTD, is as follows: the electrical signal, with its frequency greatly lower than the optical frequency, can be loaded into the opti- cal wave. Then the loaded optical wave can be delayed, and the electrical signal can be extracted from it by optical detec- tor. The extracted electrical signal and the original electrical one have identical characters, but there are some time-delay on phase position between the two signals. The True Time Delay(TTD) system based on this technological process is called the OTTD system. The integration of OTTD and phased array antenna tech- nique has overcome two technical bottlenecks in the conven- tional phased array radar, i.e., the restriction of large instan- taneous bandwidth and the beam deflection. The pure elec- trical real time delay unit has been replaced by the optical real time delay unit in optically controlled phased array an- tenna system, which makes the new OCPAA system have the virtue of low cost, light weight, small size, low power consumption and strong capability of anti-electromagnetic interference. In addition, OTTD has extensive application in optical switching technique and wireless communication technology. Compared to conventional electronic beam forming net- work, the optical beam forming network based on OTTD has many advantages, such as low power consumption, small size, large bandwidth, anti-electromagnetic interference and effectively restriction of beam deflection, etc. Thus, many OTTD systematic configuration models have been invented. However, after experiments, due to various factors, e.g. large amount of photovoltaic components and parts in optical beam forming network with its inconsistent wavelengths response, the gain difference of diversed wavelength signals caused by Erbium-Doped Fiber Amplifier (the gain uneven- ness), the inconsistent insertion loss of filters at different wavelength positions, as well as the inconsistent photoelec- tric detectors response, the optical power input in photoelec- tric detectors through channels are not equal. The optical power unequalization results in the functional deterioration of microwave in space distribution, for example, the low main-lobe peak, the high sidelobe level, and the accuracy decrease of beam-pointing. As a result, it is necessary to pre- cise control the optical signal power in each channel for the smooth operation of optical beam forming network.

We report on the properties of the Power over Fiber (PoF) transmission link using a High-Power Laser Source operating at 976 nm and using three types of optical fiber with a core diameter of 50 µm. Two step-index profile multimode optical fibers and one fiber with a gradient index were used for optical power transmission. Optical light was converted to electricity using commercially available Photovoltaic Power Convertors (PPCs) with a maximal optical input power of 1.5 W and experimental PPCs with a maximal optical input power of 4.0 W. We experimentally proved optical power transmission up to a distance of 300 m. In the case of the commercially available working PPC and using the gradient index fiber we achieved a result of 0.534 W of electrical power and using the experimental PPC we achieved 0.645 W. In the case of the step-index optical fiber, the result was 1.3 W.

Due to low attenuation in third transmission windows, single mode fibers are the most popular medium, also, in supporting transfer of optical power to various devices. For this reason ability to achieve the maximum of optical power is still actual. There are two different ways to estimate the optical power in the fiber core. The first is analysis of mathematical model in the aim of getting the best wavelength guaranteeing maximum of optical power. Second way is approximation of distribution of optical power along radius without changes of wavelength and with constant attenuation coefficient. In this paper the second way of evaluation was chosen, where distribution of optical power in single-mode fiber is approximated by Hermite or Legendre polynomials.

Analytical analysis and experimental validation of optical power estimation in V-grooved polymer optical fibers

NIST has completed commissioning a new, state-of-the-art cryogenic primary standard for optical fibre power measurement and calibration. It establishes for the first time, a direct traceability route between the device under test and primary standard. Two silicon micro-machined planar detectors, with vertically aligned carbon nanotube absorbers, thin film tungsten heaters and superconducting resistive transition edge temperature transducers, form the basis of the radiometer. Magnetic phase change thermal filters ensure noise-free operation at 7.6 K. Measurement repeatability below 50 ppm is routinely achieved during a measurement cycle of 30 min. The system operates at a nominal radiant power level of 200 µW (−7 dBm). The expanded measurement uncertainty at k = 2 is 0.4%, a 20% improvement on NIST’s current optical fibre power Calibration and Measurement Capability.The performance of the new standard was established by comparing it to our current standard, using four transfer detectors, at nominal wavelengths 850 nm, 1295 nm and 1550 nm. The comparison agreed within the combined expanded measurement uncertainty of 0.6%. Whilst the new standard is intended primarily to service the telecommunications industry, it is limited in use only by available sources and optical fibre.

Optical signal power estimation utilizing an improved optical fiber identifier is experimentally evaluated. In order to realize fine measurement, a mechanical bend adjuster and fiber guides attached to both side of the identifier are introduced. The former is useful for stabilizing the identifier operation in consequence of well controlled bend of the test fiber. The latter is effective for eliminating influence of fiber handling. As a result, standard distribution of the measured optical power of less than 0.16dB is obtained, which seems to be enough small for the field use.

We have designed and built an optical fibre power detector based on a large-area silicon PIN photodiode and a concave mirror in a wedge-trap configuration. The detector was designed as a high-accuracy transfer standard for near IR (835-865 nm) optical fibre power measurements with multimode fibre-ribbon cables in a manufacturing-production environment. Additional requirements were that the detector be insensitive to the input beam geometry, and able to accommodate different optical fibre connector types, collimated laser light, and highly diverging light from optical fibres. Four identical copies of the detector were evaluated at the NIST Laser Sources and Detectors Group calibration facility and one was tested in the manufacturing environment. The spatial and angular responsivity was highly uniform and varied less than 1% for angles of incidence ranging from to . Absolute spectral responsivity measurements, for collimated and diverging light input wavelengths ranging from 672-852 nm, showed quantum efficiencies as high as 99%. Linearity measurements from a few nanowatts to a few milliwatts indicated a nonlinearity of only 0.05%.