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"Pengguna komunikasi memerlukan sistem komunikasi yang efektif digunakan kapanpun, dimanapun dan di semua media yang diinginkan. Sistem komunikasi tersebut lebih efektif dilakukan oleh jaringan tanpa kabel dengan memanfaatkan teknologi radio over fiber (ROF). Sistem jaringan ROF yang banyak digunakan adalah jaringan RF yang menggunakan serat optik mode tunggal. Untuk itu diperlukan divais laser semikonduktor yang mempunyai noise dan distorsi rendah pada frekuensi tinggi. Pada penelitian ini dilakukan studi mengenai teknologi informasi, ROF dan laser semikonduktor. Kemudian dirancang secara optimal laser yang sesuai aplikasi ROF yaitu laser Surface Emitting Distributed Feedback (SEDFB). Pemodelan dimulai dari pemilihan material yang sesuai dengan aplikasi yang diinginkan, penentuan indeks bias dan ketebalan dari setiap lapisan penyusunnya, sampai optimalisasi parameter-parameter kerjanya, seperti confinement factor ( ??), far field, dan arus ambang. Dibutuhkan optimalisasi tebal lapisan di daerah aktif dan lapisan separated confinement heterostructure (SCH) pada laser yang menyeluruh agar tidak menurunkan kinerja parameter lain. Dari hasil simulasi didapat struktur ridge SEDFB menghasilkan operasi single mode 1550 nm dengan optical confinement factor 0,186, sudut keluaran cahaya (far field divergence) 450, optical loss 0,003 cm-1, interval grating duty cycle antara 0,5-0,.6 dan loss permukaan 24 cm-1 dan efisiensi struktur yang menghasilkan single lobe sebesar 41,78%.

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Present consumers need reliable and cost effective communication system that can support anytime, anywhere, and anymedia they want. Communication system will be effective with wireless using radio over fiber (ROF) technology. Link ROF system is most common RF transmission uses single mode optic fiber. That purpose, it needs semiconductor laser device which low noise dan low distortion at high frequencies. This Research study information technology, ROF and semiconductor laser. Then, optimum laser design due to ROF application in surface emitting distributed feedback (SEDFB) laser.

Start modeling from material selection due to application it want, determined refractive index and determined thin composition layer, also work parameter optimum is confinement factor ( ??), far field, dan threshold current. This structure need optimum layer thin in active region and separated confinement heterostructure (SCH) layer for other work parameter do not breakdown. The simulation yielded ridge SEDFB structure which optical confinement factor 0,186, far field divergence 450, optical loss 0,003 cm-1, grating duty cycle interval0,5-0,.6, surface loss 24 cm-1 dan output efisiency laser of single lobe 41,78%."

"ABSTRACTThe frequency dobled Rd: YAG laser (532 nm/10ns, 15mj/pulse) uses a pulsed, frequency dobled; which provides a monochromatic, energy source with extremely high peak power and to has capability to develop of latent fingerprint on various surface. In the porous surfaces, this laser to has superiority, the compared with the development another methods, like powder and chemical method in latent fingerprint development. The high peak power of the laser causes Palmar sweat: contain a variety compounds, among them amino acids, oils, enzymes, vitamins and other chemicals with in the print to fluoresce. Some latent fingerprints will fluoresce in their natural state during exposure to this laser energy. The natural state fluorescing prints make can be documented and recording by high-resolution TV cameras and monitor for maximum sensitivity. The next step, the compare latent fingerprints products with visible impression by comparable instruments, see patterns of the friction ridges and be found same amount of their galton detail. "

"The purpose of this reserach is to find out the influence of laser shooting to the ovaries stem of eye,ablation of crab's eye to the level of egg's maruty,the diameter of eggs and the number of eggs scylla serrata....."

"ABSTRACT

Probing of the atmospheric parameters have been done by many scientists since a century ago up to present with various techniques. A simple system of laser radar without using any collimated beam but a reflected mirror as transmitter and a small cassegranian type (10.5 an in diameter) telescope as receiving was constructed to investigate the relative Mie backscattering coefficient by utilizing a nitrogen laser as a light source in the range of measurement bellow 1 Km. The backscattered light received by the receiving telescope is converted into electric current by photomultiplier and is shown and known as "A scope" display on an oscilloscope. SNR of the signal from photomultiplier was increased by using a boxcar integrator and its output could be recorded with XY recorder."

"ABSTRACTLaser induced thin film production (LITFP) technique was employed for making plumbum (Pb) thin film by nitrogen laser deposition in miniature scale. The energy of nitrogen laser operated at 12.5 kv, 90 torr was 3.5 mj with 5 ns pulse duration, thus producing peak power at around 0.7 MW. Pb plasma of 1 cm diameter was generated in each laser bombardment, producing thin film above the glass substrate. The thin film characteristics were measured by means of their thickness and surface morphology using scanning electron microscope (SEM). It was proved that there was a linear relationship between the number of laser shots and film thickness."

"Development of optical fiber communication system is mainly due to the progressive influence of optical source. Laser diode as optical source in optical transmission system is of great attention because laser diode produces coherent monochromatic-light. Furthermore, laser diode has a high quantum efficiency, can be modulated at a very high speed, has small size and compact. The application of such optical source is also wide, ranging from optical signal communication to radar optics. Therefore, laser diode is considered to be a key component in optoelectronic system. In this study, an experimental model of analog optical transmission system with laser diode as optical source at wavelength of 0.79 pm has been designed and constructed. The design and construction include optical and electronic circuits. Design description at the wavelength used in this study is briefly described. The characteristics of the system was evaluated by measuring the frequency responds of photo detector, the transmission bandwidth and the loss of the system. The result shows that the frequency responds of the photo detector limits the transmission bandwidth of the whole system. On the other hand, by the use of the selfoc lens for coupling laser diode to fiber line, a coupling efficiency as high Es 55 % has been achieved. Based on the evaluation on the result obtained for the experimental model the practical applicability of the system is pointed out."

"Kopling antara amplifier permukaan miring dan fiber taper lens-ended diselidiki secara teori. Penelitian teori didasarkan pada model gelombang bidang tiga dimensi yang dihitung melalui pergeseran fasa akibat permukaan iring. Kopling diselidiki berkenaan dengan parameter-parameter berkas dari pandu gelombang amplifier lens-ended, dan juga berkenaan dengan posisi fiber. Terjadinya rugi-rugi kopling karena permukaan miring dan karena variasi dari uji lens yang terbaik, rugi untuk permukaan miring 10° ditemukan lebih kecil dari 0.5 dB dibandingkan amplifier permukaan normal.

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The coupling between angled-facet amplifiers and tapered lens-ended fibers is investigated theoretically. The theoretical investigation is based on a three-dimensional plane wave model which accounts for the phase differences introduced by the angled facets. The coupling is investigated with respect to the beam parameters of the amplifier wave guids and the tapered lens-ended fiber, and also with respect to the fiber position. For optimized lens radii the excess loss for 0l0° facet angle is found to be less than 0.5 dB compared to a normal facet amplifier."

"Data aktivitas pembelajaran seperti pada learning management system dapat digunakan untuk memantau kegiatan belajar. Penyajian data kegiatan pembelajaran secara real-time membantu pengambilan keputusan yang lebih cepat. Penelitian ini merancang dan mengimplementasikan sistem real-time change data capture menggunakan write-ahead logging dan distributed stream processing untuk learning analytics di Fakultas Ilmu Komputer Universitas Indonesia (Fasilkom UI). Data yang disajikan berasal dari learning management system dan sistem presensi berbasis smart card. Dengan real-time change data capture menggunakan Debezium, data dapat disajikan secara real-time dan ringan dalam membebani sistem sumber data. Sistem menggunakan Apache Kafka sebagai message queue dan Apache Flink untuk melakukan distributed stream processing. Data disajikan dalam dashboard visualisasi menggunakan Grafana. Aktivitas pembelajaran yang disajikan secara real-time pada dashboard dapat digunakan untuk melihat pola kegiatan belajar mahasiswa dan membantu pengambilan keputusan.

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Learning activity data such as the learning management system can be used to monitor learning activities. Presentation of learning activity data in real time helps faster decision making. This research design and implement a real-time data capture change system using write-ahead logging and distributed stream processing for learning analytics at the Faculty of Computer Science, University of Indonesia (Fasilkom UI). Data comes from learning management systems and presence-based systems smart card. With real-time change data capture using Debezium, data can be presented in real-time while not overloading the data sources. The system uses Apache Kafka as a message queue and Apache Flink to do distributed stream processing. Data is presented in a visualization dashboard using Grafana. Learning activities data that are presented on the real-time dashboard can be used to see patterns of student learning activities and assist decision making."