Long-wavelength InGaAsP/InP multiquantum well distributed feedback and distributed Bragg reflector lasers grown by chemical beam epitaxy
Long-wavelength InGaAsP/InP multiquantum well distributed feedback and distributed Bragg reflector lasers grown by chemical beam epitaxy
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DOI：
10.1109/3.299459
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发表时间：
1994-06
影响因子：
2.5
通讯作者：
W. Tsang;Ming C. Wu;Young-Kai Chen;F. Choa;R. Logan;S. Chu;A. Sergent;P. Magill;K. Reichmann;C. Burrus
中科院分区：
文献类型：
--
作者：
W. Tsang;Ming C. Wu;Young-Kai Chen;F. Choa;R. Logan;S. Chu;A. Sergent;P. Magill;K. Reichmann;C. Burrus
利用化学束外延（CBE）成功制备了长波长InGaAsP低阈值电流指数耦合和增益耦合DFB激光器。对于指数耦合DFB激光器，埋地异质结构6 qw DFB激光器（250 /spl mu/m长，劈裂）工作功率为1.55 /spl mu/m，连续波阈值电流为10-15 mA，斜率效率高达0.35 mW/mA（两个方面）。侧模抑制比（SMSR）高达49 dB。激光器在相同的范围内工作，即使在高温（70/spl度/C检查）。对于增益耦合的DFB激光器，增益耦合是通过使用InGaAsP四元光栅或量子阱光栅来吸收DFB发射来实现的。特别是量子阱光栅的使用，极大地促进了光栅的可再生再生（无缺陷）和耦合系数的控制。连续波阈值电流仅在250-/spl mu/m时为10-15 mA， 250-/spl mu/m和500-/spl mu/m时为13-18 mA。坡度效率很高，/spl sim/0.4 mW/mA（两个方面）。在整个电流范围内，SMSR高达52 dB，保持在相同的DFB模式，SMSR保持在/spl sim/50 dB。线宽/倍频/功率产品为1.9-4.0，最小线宽为1.8-2.2 MHz。在2.5 Gb/s调制下，没有检测到啁啾。与指数耦合DFB激光器不同的是，当偏置高于阈值时，模式分割事件会缓慢减少，而当偏置接近阈值（/spl gsim/0.95 I/sub - th/）时，模式分割事件会急剧关闭。在230 km的放大光纤系统中，以1.7 Gb/s的速度使用这些激光器作为源，在10/sup -11/ BER的传输实验中测量到非常小的色散损失为1.0 dB。在这些增益耦合DFB激光器中没有观察到自脉动。这些增益耦合DFB激光器实现了4ghz的增益切换，光调制深度为100%，FWHM脉冲宽度为23 ps。峰值功率为/spl sim/72 mW，频宽为0.14 nm。我们还利用CBE技术制备了InGaAs/InGaAsP多量子阱DBR激光器。利用均匀的厚度增长和适当的弱光栅和长光栅设计，获得了创纪录的58.5 dB的高SMSR。>
We demonstrated the successful operation of long-wavelength InGaAsP low threshold-current index-coupled and gain-coupled DFB lasers grown by chemical beam epitaxy (CBE). For index-coupled DFB lasers, buried-heterostructure six-QW DFB lasers (250 /spl mu/m long and as-cleaved) operated at 1.55 /spl mu/m with CW threshold currents 10-15 mA and slope efficiencies up to 0.35 mW/mA (both facets). A side-mode suppression ratio (SMSR) as high as 49 dB was obtained. The lasers operated in the same range even at high temperatures (70/spl deg/C checked). For gain-coupled DFB lasers, gain-coupling is accomplished by using a InGaAsP quaternary grating or quantum-well grating that absorbs the DFB emission. The use of a quantum-well grating, in particular, greatly facilitates the reproducible regrowth (defect-free) over grating and the control of the coupling coefficient. CW threshold currents mere in the range of 10-15 mA for 250-/spl mu/m and 13-18 mA for 250-/spl mu/m and 500-/spl mu/m cavities, respectively. Slope efficiencies were high, /spl sim/0.4 mW/mA (both facets). SMSR was as high as 52 dB and remained in the same DFB mode with SMSR staying /spl sim/50 dB throughout the entire current range. Linewidth/spl times/power products of 1.9-4.0 mere measured with minimum linewidths of 1.8-2.2 MHz. No detectable chirp was measured under 2.5 Gb/s modulation. Unlike index-coupled DFB lasers in which mode partition events decrease slowly even when biased above threshold, these lasers have mode partition events shut off sharply as bias approaches threshold (/spl gsim/0.95 I/sub th/). A very small dispersion penalty of 1.0 dB was measured at 10/sup -11/ BER in transmission experiments using these lasers as sources at 1.7 Gb/s over an amplified fiber system of 230 km. No self-pulsation was observed in these gain-coupled DFB lasers. Gain-switching at 4 GHz with a 100% optical modulation depth and a FWHM pulse width of 23 ps was achieved with these gain-coupled DFB lasers. The peak power was /spl sim/72 mW and the FWHM bandwidth was 0.14 nm. We also fabricated InGaAs/InGaAsP multiquantum-well DBR lasers by CBE. Taking advantage of uniform thickness growth and proper design of weak and long gratings, a record high SMSR of 58.5 dB was obtained. >