서지주요정보
반도체 레이저의 대신호 변조특성 및 초단 광펄스 발생에 관한 연구 = Large signal modulation characteristics of semiconductor lasers and ultra-short optical pulse generation
서명 / 저자 반도체 레이저의 대신호 변조특성 및 초단 광펄스 발생에 관한 연구 = Large signal modulation characteristics of semiconductor lasers and ultra-short optical pulse generation / 이용탁.
저자명 이용탁 ; Lee, Yong-Tak
발행사항 [대전 : 한국과학기술원, 1990].
Online Access 제한공개(로그인 후 원문보기 가능)원문

소장정보

등록번호

8000230

소장위치/청구기호

학술문화관(문화관) 보존서고

DAP 9012

SMS전송

도서상태

이용가능

대출가능

반납예정일

초록정보

Harmonic characteristics of semiconductor lasers and generation of ultrashort optical pulse train by gain-switching and fiber-optic pulse compression scheme are studied, including the following major areas: i) Laser parameter measurement by harmonic characteristics ii) Gain-switched picosecond pulse generation iii) Fiber-optic compression and separation of gain-switched pulses. Novel measurement methods of semiconductor laser parameters such as spontaneous emission carrier lifetime, photon lifetime, spontaneous emission factor, and carrier diffusion parameter are proposed, which utilize the harmonic distortion characteristics. Spontaneous emission carrier lifetime is measured by the rate of amplitude change of 3rd harmonies at threshold to the modulation frequency below a few MHz. Photon lifetime is measured by the 3rd harmonic characteristics with modulation frequency of several hundreds of MHz. Spontaneous emission factor is measured by 5th harmonic characteristics with bias current below threshold. Carrier diffusion parameter is measured by the 2nd harmonic characteristics with bias current above thresholds. It is also found that these measurement methods using harmonic characteristics are very precise ones, because they measure the relative amplitude of harmonic distortions. Picosecond optical pulse(bout 20 ps) train with single longitudinal mode and 1 Gbit/s repetition rate is obtained using a gain switching for an 1.3 μm GaInAsP/InP distributed feedback laser. A systematic investigation of pulse width and pulse waveform of gain-switched pulse including bias current dependence and current pulse amplitude dependence is carried out. It is found that the optimum condition for minimizing pulse width can be obtained at the DC bias level around the half of the threshold, which is confirmed in a numerical analysis based on the rate equations considering the gain saturation effect due to both spatial and spectral hole burning. Numerical analysis also indicate that the gain saturation effect is the major limiting factor of pulse shortening by gain-witching scheme. From the curve fitting of experimental data and the theoretical calculation for bias current dependence of pulse width, gain compression parameter $\varepsilon$ in the form of g(S)=$g_0$/(1+$\epsilon$S) is estimated about $1~2\times 10^{-17}cm^3$, which corresponds to the intraband relaxation time of 0.05~0.1 ps. A comparison of picosecond pulse measurement methods, by SHG auto-correlation and by streak camera, is discussed also. Separation and compression of pulses from a gain-switched Fairy-Pert semiconductor laser is achieved by using a dispersion-shifted optical fiber. Expermentally, 1.26μm GaInAsP/InP laser diode with 2nm mode separation in wavelength is gain-switched to generate around 26 ps pulse, which is launched into a dispersion-shifted(1.55μm) fiber with chromatic dispersion of -26ps/nm-Km at 1.26μm wavelength to produce pulse train separtated by 120 ps interval in time after propagation of 2Km. Evolution of pulse waveform is analyzed theoretically by an improved expression of semiconductor laser chirp and rate equations with consideration of gain saturation due to both spatial and spectral hole burning which is suitable for large signal modulation. A discussion is made on the possible application of this technique to a novel hybrid time/wavelength division multiplexing scheme for very high capacity signal transmission through optical fiber.

서지기타정보

서지기타정보
청구기호 {DAP 9012
형태사항 6, 169 p. : 삽도 ; 26 cm
언어 한국어
일반주기 부록 수록
저자명의 영문표기 : Yong-Tak Lee
지도교수의 한글표기 : 이상수
지도교수의 영문표기 : Sang-Soo Lee
학위논문 학위논문(박사) - 한국과학기술원 : 물리학과,
서지주기 참고문헌 수록
주제 Semiconductor lasers.
Pulse generators.
반도체 레이저. --과학기술용어시소러스
변조 분광학. --과학기술용어시소러스
광 펄스. --과학기술용어시소러스
펄스 발생기. --과학기술용어시소러스
Modulation.
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