The MTF (modulation transfer function) has been used to evaluate the performance of optical systems. More accurate access to on-orbit MTF opens the way to enhance images so that we can deduce more information from the images of IKONOS, OrbView, or SPOT. Generally, the MTF was assessed using various methods such as the point source method and the knife-edge method etc. In this paper, the value of the slanted-edge method is investigated as a tool to assess the on-orbit MTF. The slanted-edge method is the ISO 12233 standard for the MTF measurement of electronic still-picture cameras. The method is adapted to estimate the MTF values of line-scanning telescopes. We applied the method to measure the MTF of high resolution satellite images and also, we compared the MTF measurement with that of the knife-edge method applied to EOS-C test images to increase the confidence on MTF measurement on EOS-C. EOS-C is a 2.5m resolution satellite sensor for SI-200 satellite which is under the development by Satrec Initiative. The MTF measured from this method is used for the MTF compensation of satellite images by generating the MTF convolution kernel based on the PSF (point spread function).

We have explicated the Goos-Hänchen (GH) shift in a μm-order Kretchmann-Raether configuration embedded in an optical waveguide structure by using the finite-difference time-domain method. For optical waveguide-type surface plasmon resonance (SPR) devices, the precise derivation of the GH shift has become critical. Artmann’s equation, which is accurate enough for bulk optics, is difficult to apply to waveguide-type SPR devices. This is because Artmann's equation, based on the differentiation of the phase shift, is inaccurate at the critical and resonance angles where drastic phase changes occur. In this study, we accurately identified both the positive and the negative GH shifts around the incidence angle of resonance. In a waveguide-type Kretchmann-Raether configuration with an Au thin film of 50 nm, positive and negative lateral shifts of −0.75 and + 1.0 μm are obtained on the SPR with the incident angles of 44.4 ° and 47.5 °, respectively, at a wavelength of 632.8 nm.

Although the field applications of conventional optical feedforward transmitters were limited due to stationary transmission distance, the proposed optical feedforward transmitter overcame the limitations using vector control theory. A vector control circuit achieved perfectly the third-order intermodulation (IMD3) suppression regardless of distance or dispersion. The experimental results show that the IMD3 for two-tones was suppressed by maximum 38 dB even after 20 km. This work shows that the proposed optical feedforward transmitter is applicable to optical fiber radio transmission system.

We have identified the charge accumulation effects in a resonant tunneling diode for the application of optical switching by observing the hole tunneling peak under illumination with a Ti:sapphire laser. Two mechanisms, photocurrent and charge accumulation, are rigorously examined to determine which one is the dominant effect for optical switching by comparing the current–voltage (I–V) characteristics for forward biases and reverse biases. It is believed that the hole accumulation effect in the depletion region, which results in the hole tunneling current, is responsible for the shift of the I–V curves.

The importance of capacitively coupled radio frequency (rf) discharges has resulted in many attempts, by experiment and by simulation, to understand the dynamics of the discharge. Because of the time varying nature of the sheath potential, the sheath region is of special interest in these plasmas. Direct measurements are reported of the sheath electric fields in a helium plasma obtained using a laser induced fluorescence method. In the interpretation of these measurements, the time dependence of the fluorescence spectrum had to be considered. The measured electric field distributions can be used to deduce sheath widths.

In this letter, a new complementary Hartley (C-Hartley) voltage controlled oscillator (VCO) with fully differential outputs is proposed, in which the self-biasing configuration is introduced to solve the biasing difficulty of a Hartley VCO by employing a five-port transformer. The proposed C-Hartley VCO with the center frequency of 5.6 GHz is implemented in a 1P6M 0.18 μm CMOS process. The measurement result shows that the phase noise is -123.6 dBc/Hz at 1 MHz offset frequency, while dissipating 6.5 mA from 1.6 V supply with the FOM of -188.5 dBc.