Browsing by Author "Ozharar, Sarper"

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Absolute phase noise analysis of a harmonically modelocked semiconductor laser
(Optica Publishing Group (formerly OSA), 2017) Ozharar, Sarper; Ozdur, Ibrahim; 0000-0001-6452-0804; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü; Ozdur, Ibrahim
We have designed and built a fiber coupled semiconductor laser at 1550 nm, which is harmonically mode-locked at 10 GHz by an external RF oscillator. The absolute phase noise of the laser is measured and discussed for two different cavity lengths.
Amplitude noise suppression by intracavity phase modulation in a harmonically mode-locked laser
(ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND, 2018) Ozharar, Sarper; Ozdur, Ibrahim; 0000-0001-6452-0804; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü
A fiber coupled semiconductor ring laser that employs both an amplitude and a phase modulator was built and actively harmonic mode-locked at a repetition rate of 10 GHz. The phase modulator was driven at the cavity fundamental frequency and its effects on the optical spectrum and the optical pulse train were analyzed. The intracavity phase modulation at the cavity fundamental frequency resulted in 40% lower optical pulse amplitude fluctuations and improved the stability of the optical spectrum. (C) 2018 Elsevier Ltd. All rights reserved.
The Effects of Intracavity Phase Modulation and Extracavity Optical Filtering on Amplitude Noise of Mode-Locked Pulse Trains
(IEEE, 345 E 47TH ST, NEW YORK, NY 10017 USA, 2018) Ozharar, Sarper; Ozdur, Ibrahim; 0000-0001-6452-0804; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü
An actively mode-locked, fiber-coupled semiconductor ring laser that employs both a phase modulator and an amplitude modulator was built. The laser was mode locked by loss modulation at 10 GHz and the intracavity phase modulator was driven at the cavity fundamental frequency of 1.63 MHz. The effects of the intracavity phase modulation on the stability of the optical spectrum, the timing jitter, and the amplitude noise of the pulse train was analyzed. It was found that using this method, the amplitude fluctuation can be reduced by 40%, and the stability of the optical spectrum can be improved while keeping the phase noise of the system unchanged.
Multifunction optoelectronic gate
(WILEY, 2015) Ozdur, Ibrahim Tuna; Ozharar, Sarper; Delfyett, Peter J.; 0000-0001-6452-0804; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü; Ozdur, Ibrahim Tuna
A multifunction optoelectronic gate that can perform as any desired logic gate of two variables was theoretically proposed and a simplified version is experimentally demonstrated. The proposed optoelectronic gate is dynamically configurable, and being wavelength independent, it can act on multiple input optical bits and realize different functions simultaneously.
RF injection locked 18 GHz regeneratively mode-locked semiconductor laser
(OPTICAL SOC AMER, 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA, 2018) Oran, Abdullah; Ozharar, Sarper; Can, Gokhan; Olcer, Ibrahim; Ozdur, Ibrahim; AGÜ, Mühendislik Fakültesi, Elektrik & Elektronik Mühendisliği Bölümü;
In this manuscript, a semiconductor based fiber ring cavity mode-locked laser regeneratively driven at 18 GHz is presented. The optical spectrum of the laser is centered at 1578 nm. The laser is RF injection locked via an external source at 18 GHz. The phase noise of the mode-locked laser is measured and the integrated timing jitter was found to be 10.8 fs (from 100 Hz to 20 MHz) and 13.3 fs (from 100 Hz to Nyquist frequency). The integrated amplitude fluctuation (from 100 Hz to 20 MHz) was less than 0.02%. The laser phase and amplitude noise responses to various injected RF power levels were also investigated. The injection RF power has significant effect on the phase noise and the best jitter value is around 40 dB lower than the cavity regenerated RF power. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
RF phase noise filtering properties of an actively mode-locked laser
(WILEY, 111 RIVER ST, HOBOKEN 07030-5774, NJ USA, 2018) Mbonde, Hamidu; Ozharar, Sarper; Ozdur, Ibrahim; 0000-0001-6452-0804; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü
In this article, we are presenting the experimental results and theoretical analysis of radio frequency (RF) phase noise filtering properties of a high Q cavity actively driven mode-locked laser. The experimental results show that, the phase noise of a 10 GHz RF tone can be filtered by at least 10 dB at 200 kHz offset frequency. A theoretical analysis on the limits of phase noise filtering due to the spontaneous emission and the frequency mismatch between the laser cavity modes and the synthesizer frequency is also included.
Simultaneous low noise radio frequency tone and narrow linewidth optical comb generation from a regeneratively mode-locked laser
(SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA, 2014) Ozdur, Ibrahim; Ozharar, Sarper; Delfyett, Peter J.; AGÜ, Mühendislik Fakültesi, Elektrik & Elektronik Mühendisliği Bölümü;
A regeneratively mode-locked laser with simultaneous low noise radio frequency (RF) tone and optical comb generation is presented. The laser does not need any external RF signal and emits a pulse train at similar to 10 GHz repetition rate with a 1.5-ps optical pulse width after compression. The generated RF tone has a signal-to-noise ratio of 121 dB/Hz and an RF fluctuation of 10(-9) over 0.1 s. The optical frequency comb spacing is also at similar to 10 GHz and the optical comb tooth has a linewidth of <1 kHz. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)