Time-dependent Analysis of Optical Receivers Using Receiver Eigenmodes

서경희,Alan E. Willner,이재승 한국광학회 2013 Current Optics and Photonics Vol.17 No.4

Using receiver eigenmodes, we perform a time-dependent analysis of optical receivers whose optical inputs are corrupted by the amplified spontaneous emission. We use Gaussian receivers for the analysis with Gaussian input pulses. We find the number of contributing eigenmodes increases as the measurement time moves from the pulse center towards the pulse edges at the output of the optical receiver’s electrical filter. This behavior is dependent on the bandwidth ratio between the optical and the electrical filters as well as the input pulse’s time width.

위치변위 레이저 간섭계용 송수신 광학계의 설계 및 분석

윤석재,임천석 한국광학회 2017 한국광학회지 Vol.28 No.2

We present a new type of receiver-transmitter optical system that can be adapted to the sensor head of a displacement-measuringinterferometer. The interferometer is utilized to control positioning error and repetition accuracy of a wafer, down to the orderof 1 nm, in a semiconductor manufacturing process. Currently, according to the tendency of scale-up of wafers, an interferometeris demanded to measure a wider range of displacement. To solve this technical problem, we suggest a new type of receivertransmitteroptical system consisting of a GRIN lens-Collimating lens-Afocal lens system, compared to conventional receivertransmitterusing a single collimating lens. By adapting this new technological optical structure, we can improve coupling efficiencyup to about 100 times that of a single conventional collimating lens.

광 SCM 전송방식에서 MZ 변조기를 통과한 DS-CDMA 신호의 레이크 수신기에 의한 성능개선

김회준,이도현,신성일,임명섭 한국전자파학회 2003 한국전자파학회논문지 Vol.14 No.11

It is expected in the future that the demand of optical subcarrier multiplexing system, in which a number of small size base stations with only antenna and RF transmission are connected to central station using optical fiber, will be increased in the CDMA digital cellular mobile communication network. In this paper, in order to analysis the performance of optical SCM system fur CDMA RF signal transmission, MZ modulator is modelled as a non-linear transfer function with cubic operation. The performance degradation due to multipath signals and other user signals through MB modulator is analyzed and the performance is improved using the Rake receiver. 향후 CDMA(Code Division Multiple Access) 디지털 셀룰러 이동통신망에서는 안테나와 RF(Radio Frequency) 송ㆍ수신기만을 갖춘 다수의 소형 기지국들을 광섬유를 이용하여 중앙국으로 연결시키는 SCM(Subcarrier Multiplexing) 광링크 시스템의 수요가 많이 예상된다. 본 논문에서는 CDMA RF 신호전송을 위한 SCM 광링크 시스템의 성능분석을 위하여 Mach-Zehnder변조기(MZM)의 전달함수를 입력신호가 3제곱이 되어 출력되는 비선형으로 모델링 하였다. 그리고 페이딩 채널 영향으로 다중경로 신호성분을 가지고 소형 기지국에 수신되는 여러 다중 가입자 CDMA 신호들이 MZM을 통과한 후 복조되는 과정에서 생기는 다중접속 간섭신호를 유도하여 성능분석을 하고 레이크 수신기를 이용하여 성능개선을 하였다.

Method of Crosstalk Analysis for CO-ORMDM Systems

Kyung Hee Seo,Jae Seung Lee 한국광학회 2024 Current Optics and Photonics Vol.8 No.2

Recently, a new kind of optical multiplexing called optical-receiver-mode (ORM)-division multiplexing (ORMDM) has been proposed, in which an optical channel is a linear sum of ORM subchannels modulated independently. Using coherent-optical (CO) techniques, it has been reported that COORMDM communication systems can have very high spectral efficiencies (SEs). To estimate the SEs of CO-ORMDM communication systems, we introduce a new method of crosstalk analysis. Using this method, we can allocate quadrature-amplitude-modulation (QAM) codes and QAM step sizes unevenly over ORM subchannels to obtain higher SEs. With 50 Gaussian ORMs, we obtain a SE of up to 15.29 bit s<SUP>−1</SUP> Hz<SUP>−1</SUP>.

주광이 무선 광통신 시스템의 수신 감도에 미치는 영향

박기홍,김훈 한국광학회 2020 한국광학회지 Vol.31 No.6

We evaluate the degradation of receiver sensitivity induced by direct and indirect exposure to solar irradiance in free-space optical communication systems. For this purpose, we calculate the variances of numerous noise components arising from solar irradiance, and then estimate the receiver sensitivity penalties for intensity-modulation/direct-detection and coherent systems. The results show that the penalties are less than 1.3 dB when indirect sunlight impinges on the detector, regardless of the system. However, the sensitivity penalties are estimated to be larger than 30 dB when the sunlight is directly incident upon the receiver. These penalties are barely reduced if we insert an optical polarizer, or if we adjust the bandwidth of an optical filter at the receiver to be as narrow as the signal’s bandwidth.

광통신시스템의 PIN 수신기 수신감도 해석

김선엽(Kim, Sun-Youb) 한국산학기술학회 2011 한국산학기술학회논문지 Vol.12 No.5

광통신 시스템에서 신호와 부가적인 잡음의 통계적인 특성에 대해 다양한 방법으로 평가하는 것은 시스템 의 성능 최적화를 위해 필수적인데, 본 연구에서는 수신기의 성능 평가 방법으로 다양한 에러 확률을 대역폭과 비트 수의 함수(m)로 표현하여 수신기의 성능을 평가를 통하여 광통신시스템에서 사용되고 있는 PIN 수신기의 수신감도 를 해석하였고 시뮬레이션을 통해 이를 확인하였다. 그 결과 m=20인 경우, PIN 수신기의 수신 감도는 주어진 에러 확률을 유지하기 위해 대략 9.2×10<SUP>4</SUP> 광자/비트 정도가 필요함을 확인 할 수 있었다. It is essential to various evaluate about statistic character of the signal and additional noise for optimization of the optical communication system. We expressed various error probability with the m which was bandwidth and a bit numerical function and carried out performance evaluation of a PIN receiver. This research analyzed the receiving sensitivity of the PIN receiver and verified reception sensitivity through computer simulation in the optical communication system. As a result, the receiving sensitivity for PIN receiver are 9.2×10<SUP>4</SUP> photon/bit for given error probability.

Advancement of CMOS Transimpedance Amplifier for Optical Receiver

Md. Torikul Islam Badal,Mamun Bin Ibne Reaz,Lye Suet Yeng,Mohammad Arif Sobhan Bhuiyan,Fahmida Haque 한국전기전자재료학회 2019 Transactions on Electrical and Electronic Material Vol.20 No.2

Transimpedance amplifi er (TIA) is an essential component of optical receivers, and this type of amplifi er converts the photocurrent to a voltage signal. The overall performance of the optical receiver greatly depends on the performance of this component. Low-power, low-noise, and compact TIA has been realized in current development in CMOS technology. The high demands of an optical receiver has led to the optimization and development of the TIA designed specifi cations. However, the conventional CMOS TIA design is limited mainly because of its dependency on input node capacitance. In this article, the advancement of TIAs in data communication and instrumentation based on diff erent design architectures and performances is discussed. This review will serve as a comparative study and reference for designing fully integrated CMOS TIA for future optical receivers.

Wide receiver orientation using diffuse reflection in camera-based indoor visible light communication

Cahyadi, Willy Anugrah,Chung, Yeon Ho Elsevier 2019 OPTICS COMMUNICATIONS - Vol.431 No.-

<P><B>Abstract</B></P> <P>Camera-based visible light communication (CVLC) is a versatile and potential optical wireless communication using rapidly developing smartphone cameras as the receiver. In CVLC, the provision of both flicker-free illumination and high data rate has been a challenging issue. To some extent, however, this issue can be resolved by utilizing a rolling shutter property that is inherited from complementary metal-oxide semiconductor sensors adopted in all smartphone cameras. We propose a practical and versatile wide receiver orientation in CVLC on the basis of this rolling shutter property. That is, unlike previous studies focused on either a line-of-sight (LOS) or non-line-of-sight (NLOS) link only, an orientation independent rolling shutter based CVLC is presented. Based on a unique method of exploiting diffuse reflection of illumination, a wide orientation of the receiver is adequately supported in an indoor environment, thus making the CVLC data reception more practical and convenient. A special transmitter for this wide orientation is designed to ensure that adequate diffuse reflection is present in all directions, regardless of whether a LOS or NLOS link is established. In addition, adaptive algorithms are proposed to ensure an efficient and reliable wide orientation CVLC. Experiments are conducted and analyzed for practical orientations of the receiver in an indoor CVLC environment. While providing sufficient illumination and various orientations, it is found that the proposed scheme achieves a data rate of 6.72 kbps at a distance of up to 50 cm in a small-scale indoor experiment.</P>

전광섬유형 $2{\times}32$ 스프리터 제작과 이를 이용한 Ethernet PON 시스템의 상향통신채널 성능평가

장진현,김준환,신동호,Jang, Jin-Hyeon,Kim, Jun-Hwan,Shin, Dong-Ho 한국정보통신설비학회 2005 정보통신설비학회논문지 Vol.4 No.2

All-optical fiber-type $2{\times}32$ splitters for an Ethernet PON (passive optical network) were fabricated by using a FBT (fiber biconical tapered) process and the performance of the splitters was tested in upstream transmission of the EPON system. The $2{\times}32$ splitters was obtained by cascading $1{\times}4$ splitters fabricated by a conventional FBT process and showed -18 dB of insertion loss with 1.5 dB uniformity of output power at each channel and -0.1 dB of polarization dependent loss. The insertion loss variation was below 0.1 dB at the temperature range of $-40^{\circ}C\;to\;80^{\circ}C$. For upstream channel transmission test in the EPON system were a Zig board and a burst mode receiver. Zenko-made optical module was used for the burst mode receiver by adding functions of serializer/deserializer and clock data recovery, a Virtex II pro20 chipset and Vitesse VSC7123 were used in the Zig board for characterizing the burst mode and in the clock data recovery chipset, respectively. Startup acquisition lock time and data acquisition lock time were measured to be 670ns and 400ns, respectively, in the upstream channel transmission of the EPON system adapting the $2{\times}32$ splitter fabricated in this work.

FTTH용 CMOS Optical Link Receiver의 설계

김규철(Kyu-Chull Kim) 大韓電子工學會 2004 電子工學會論文誌-SD (Semiconductor and devices) Vol.41 No.1