Browsing by Author "Liao, YS"

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10Gbps operation of a metamorphic InGaP buffered In0.53Ga0.47As p-i-n photodetector grown on GaAs substrate - art. no. 602023
(2005)
Liao, YS
;
Lin, GR
;
Lin, CK
;
Chu, YS
;
Kuo, HC
A novel top-illuminated In0.53Ga0.47As p-i-n photodiodes (MM-PINPD) grown on GaAs substrate by using a linearly graded metamorphic InxGa1-xP (x graded from 0.49 to 1) buffer layer has been demonstrated on the SONET OC-192 receiving performance. With a cost-efficient TO-46 package, the MM-PINPD at data rate of 10 Gbit/s can be obtained at minimum optical power of -19.5 dBm. At wavelength of 1550nm, the dark current, optical responsivities, noise equivalent power, and operational bandwidth of the MM-PIND with aperture diameter of 60 mu m are 13 pA, 0.6 A/W, 3.4 x 10(-15) W/Hz(1/2), and 8 GHz, respectively. All the parameters are comparable to those of similar devices made on InP substrate or other InGaAs products epitaxially grown on an InGaAlAs buffered GaAs substrate. The performances of the MM-PINPD on GaAs are analyzed by impulse injecting of 1.2-ps pulse-train, eye pattern at 10Gbps, and frequency response from VNA.
A 3.5-ps mode-locked semiconductor optical amplifier fiber laser generated by 60-ps backward optical dark pulse-train injection
(2005)
Chiu, IH
;
Liao, YS
;
Chang, YC
;
Lin, GR
;
光電工程學系
The relationship between the backward optical injection waveform and the mode-locked Pulse shape of semiconductor optical amplifier fiber laser (SOAFL) is studied. The SOA plays both the roles of a gain medium and an optically controlled modulator in this work. The injected optical comb-like bright and dark pulse-train with 60-ps pulsewidth was generated using a Mach-Zehnder intensity modulator (MZM) which DC-biased voltage of 1.7 V and 7.2 V, respectively. The backward injection of optical dark pulse-train results in a wide gain-depletion width (and a narrow gain window) within one modulation period, which is necessary for perfect mode-locking the SOAFL. In opposite, the backward injection of short optical pulse of bright optical pulse-train only causes a less pronounced gain-depletion effect. Such a broadened gain window can hardly initiate the mode-locking process. The backward comb-like dark pulse-train modulation IS Much easier to initiate harmonic mode-locking in the SOAFL than the bright pulse-train or sinusoidal-wave, wave injection, which generates pulsewidth as short as 15 ps at 1 GHz. After propagating through 195m-long dispersion-compensating fiber, the pulsewidth of the mode-locked SOAFL can be linearly compressed to 13.5 ps. The linewidth and time-bandwidth product of the compressed SOAFL pulses are 1.78 nm and 0.8, respectively. The pulsewidth can further be nonlinearly compressed by using a 4695m-long single-mode fiber. The shortest mode-locked SOAFL pulsewidth of 3.5 ps at repetition frequency of I GHz by using cross-gain modulation technique is reported for the first time.
Comparison on the sensitivity of fiber-optic SONET OC-48 PIN-TIA receivers measured by using synchronous modulation inter-mixing technique and bit-error-rate tester
(2003)
Lin, GR
;
Liao, YS
;
光電工程學系
;
Department of Photonics
The sensitivity of SONET p-i-n photodiode receivers with transimpedance amplifier (PIN-TIA) from OC-3 to OC-48 data rates measured by using a standard bit-error-rate tester (BERT) and a novel synchronous-modulation inter-mixing (SMIM) technique are compared. A threshold inter-mixed voltage of below 15.8 mV obtained by SMIN4 method corresponding to the sensitivity of PIN-TIA receiver beyond -32 dBm determined by BERT for the SONET OC-48 PIN-TIA receivers with a required BER of better than 10(-10) is reported. The analysis interprets that the inter-mixed voltage for improving the PIN-TIA receiver sensitivity from -31 dBm to -33 dBm has to be increased from 12.5 mV to 20.4 mV. As compared to the BERT, the, SMIM is a relatively simplified and low-cost technique for on-line mass-production diagnostics for measuring the sensitivity and evaluating the BER performances of PIN-TIA receivers.
Dynamics of optical backward-injection-induced gain-depletion modulation and mode locking in semiconductor optical amplifier fiber lasers
(2004-05-17)
Lin, GR
;
Liao, YS
;
Xia, GQ
;
光電工程學系
;
Department of Photonics
The optical gain-depletion-induced mode-locking dynamics of a semiconductor optical-amplifier-based fiber ring laser (SOAFL) backward injected by a purely sinusoidally modulated or digitally encoded distributed-feedback laser diode are theoretically and experimentally demonstrated. The effect of gain depletion and waveform on the mode-locked pulse width, pulse shape, and power of the SOAFL are interpreted from theoretical simulations. The shortest pulse width of 12 ps can be generated from an optically sinusoidal-wave-modulated SOAFL. By backward injecting the SOAFL with a digitally encoded optical signal of adjustable duty cycle, one can observe the optimized gain depletion time of 400-600 ps required for mode locking the SOAFL. (C) 2004 Optical Society of America.
Harmonic injection-locking behavior of frequency-detuned optical pulse in erbium-doped fiber laser
(2004-08-01)
Lin, GR
;
Liao, YS
;
Wu, JR
;
光電工程學系
;
Department of Photonics
The harmonic injection-locking dynamics of a gain-switched laser diode (GSLD) pulse-injection-locked Erbium-doped fiber amplifier-based laser (EDFL) are studied. Under GSLD injection with a pulsewidth and an average power of 17.6ps and 0.2 mW, respectively, at a repetition frequency corresponding to the 223rd harmonic (996.8635971 MHz) of the EDFL, the pulsewidth, peak power, and phase noise of the injection-locked EDFL are broadening from 34.3 ps to 130 ps, decreasing from 1.8 W to 500 mW, and increasing from - 101.5 dBc/Hz to -86 dBc/Hz, respectively, as the repetition frequency detunes toward the injection-locking margin. The injection-locking range is from -13 kHz to +27 kHz. The peak power of the broadened pulses is greatly reduced to one third of that at the zero-detuning condition even with a detuning frequency of 5 kHz. The injection-locked EDFL pulse-train eventually disappears as the repetition frequency of the GSLD detuned beyond the injection-locking bandwidth. The timing jitter of the GSLD harmonic injection-locked EDFL remains unchanged (<0.5ps) within a positive detuning frequency of <25kHz, which is less stable at a negatively frequency-detuned regime.
Low-leakage In(0.53)Ga(0.47)As p-i-n photodetector fabricated on GaAs substrate with linearly graded metamorphic In(x)Ga(1-x)P buffer
(2005)
Lin, CK
;
Kuo, HC
;
Liao, YS
;
Lin, GR
;
光電工程學系
A novel top-illuminated metamorphic In(0.53)Ga(0.47)As p-i-n photodiodes (MM-PlNPD) grown on GaAs substrate by using a linearly graded In(x)Ga(1-x)P (x graded from 0.51 to 1) buffer layer is reported. The dark current, optical responsivities, noise equivalent power (NEP), and operational bandwidth of the MM-PINPD with aperture diameter of 60 mu m are 13 pA, 0.77/0.59 (1310/1550 nm) A/W, 6.9x10(-11) W/Hz(1/2), and 7.5 GHz, respectively. The performances of the MM-PINPD on GaAs are demonstrated to be better than those of a similar device made on InGaAs/InP substrate.
Optically heterodyne diagnosis of a high-saturation-power undoped InP sandwiched InGaAs p-i-n photodiode grown on GaAs
(2006-06-12)
Liao, YS
;
Shi, JW
;
Wu, YS
;
Kuo, HC
;
Feng, M
We demonstrate the optical heterodyne diagnostics and high saturation power characteristics of a novel undoped InP sandwiched In0.53Ga0.47As p-i-n photodiode with a partially p-doped photoabsorption layer, which is grown on a linearly graded metamorphic InxGa1-xP buffered GaAs substrate layer and exhibits an excellent low dark current density of 3.6 x 10(-7) A/cm(2). Such a top-illuminated optical receiver exhibits an illuminating window of 60-mu m diameter, which performs ultra-linear power handling capability up to 18 dBm at 1550 nm, providing a maximum photocurrent of 35 mA under a reverse bias of 9 volts. These result in extremely high current bandwidth and bandwidth-responsivity products of 350 mA center dot GHz and 4.8 GHz center dot A/W, respectively, at receiving frequency of up to 10 GHz. (c) 2006 Optical Society of America.
Sensitivity evaluation of fiber optic OC-48 p-i-n transimpedance amplifier receivers using sweep-frequency modulation and intermixing diagnostics
(2005-04-01)
Lin, GR
;
Liao, YS
;
光電工程學系
;
Department of Photonics
The sensitivity of SONET p-i-n photodiode receivers with transimpedance amplifiers (PIN-TIA) from OC-3 to OC-48 data rates, measured by using a standard bit-error-rate tester (BERT) and a novel sweep-frequency-modulation/intermixing (SMIM) technique, are compared. A threshold intermixed voltage below 15.8 mV obtained by the SMIM method corresponding to the sensitivity of the PIN-TIA receiver beyond -32 dBm determined by BERT for the SONET OC-48 PIN-TIA receivers with a required BER of better than 10(-10) is reported. The analysis interprets that the intermixed voltage for improving the PIN-TIA receiver sensitivity from -31 to -33 dBm has to be increased from 12.5 to 20.4 mV. As compared to the BERT, the SMIM is a relatively simplified, fast, and low-cost technique for on-line mass-production diagnostics for measuring the sensitivity and evaluating the BER performances of PIN-TIA receivers. (c) 2005 Society of Photo-Optical Instrumentation Engineers.
Switchable dual-wavelength NRZ-to-RZ data-format transformer using non-DC-biased and synchronously modulated laser diode
(2005-05-01)
Chang, YC
;
Lin, YH
;
Liao, YS
;
Lin, GR
;
光電工程學系
The switchable dual-wavelength and wavelength-converted nonretum-to-zero-to-return-to-zero (NRZ-to-RZ) data transformation is demonstrated by externally seeding a synchronously sinusoidal-modulated laser diode with an optical pseudorandom bit sequence data at 1 Gbps. A maximum wavelength tuning range of 30 nm with an SMSR of greater than 36 dB is obtained. 1 Gbps on/off keying of single-mode RZ data pulse-train generated by externally seeding synchronously sinusoidal-modulated laser diode is demonstrated.
The detuning characteristics of rational harmonic mode-locked semiconductor optical amplifier fiber-ring laser using backward optical sinusoidal-wave injection modulation
(2005-03-01)
Lin, GR
;
Hsueh, PS
;
Wu, HH
;
Liao, YS
;
光電工程學系
The modulation waveform, power, and frequency detuning dynamics of a semiconductor optical amplifier fiber-ring laser (SOAFL) harmonic and rational-harmonic mode-locked by using backward injection of a large-signal sinusoidal-wave modulated Fabry-Perot laser diode (FPLD) are studied. The shortest pulsewidth of 53.3 ps at 1 GHz with spectral linewidth of 0.09 run at modulation power of 17 dBm can be obtained, which corresponds to a time-bandwidth product of 2.8. The threshold modulation power and the maximum frequency detuning range for harmonic mode-locking of the SOAFL are 11.5 dBm and 180 kHz, respectively. The mode-locked SOAFL gradually recovers back to sinusoidal-wave modulation mode at the detuning frequency beyond +/- 400 kHz. The pulse broadening slopes for the positive- and negative-frequency detuning regions of 0.48 and 0.375 ps/kHz are,determined, respectively. By enlarging the modulating power and detuning the modulation frequency of FPLD, the SOAFL can be rational-harmonic mode-locked up to 12 GHz with 33-ps pulsewidth.
The effect of backward injecting wavelength on the mode-locking dynamics of a semiconductor amplifier based fiber laser
(2005)
Chu, YS
;
Liao, YS
;
Lin, YH
;
Chang, YC
;
Lin, GR
The wavelength dependent mode-locking performances of a SOAFL under the backward optical injection via a sinusoidal-modulated distributed feedback laser diode (DFBLD) at 1 GHz repetition rate are characterized. The backward optical injection has to be sufficiently high to saturate a SOA and then depletes most of the excited state electrons in the SOA. In order to obtain shorter mode-locking pulsewidth, the DFBLD injecting wavelength should be slightly longer than the peak wavelength of SOA gain to benefit from shorter gain-recovery time and larger modulation depth. As the wavelength of a DFBLD approach the central wavelength of SOA, the shortest pulse was measured via a digital sampling oscilloscope (DSO). The pulses can also be obtained by DFBLD backward injection at 1535 rum in feedback of SOAFL, leading to the optimized pulsewidths of 22.7 ps.