Room-temperature CW operation of 1.60 ?m GaInAsP/InP buried-heterostructure integrated laser with butt-jointed built-in distributed-Bragg-reflection waveguide

CW operation of a 1.60 ?m GaInAsP/InP buried-heterostructure integrated laser with butt-jointed built-in distributed-Bragg-reflection waveguide (BH BJB DBR integrated laser) was achieved at room temperature. Single longitudinal-mode operation at fixed mode was obtained in a temperature range of about 60 deg C, under the CW condition, and it was also maintained under rapid direct modulation of 1.6 GHz.     

Short-coupled-cavity (SCC) InGaAsP injection lasers for CW and high-speed single-longitudinal-mode operation

CW and high-speed (100 ps pulse) single-longitudinal-mode operation has been achieved with a short-coupled-cavity (SCC) InGaAsP injection laser (in the 1.3 ?m to 1.55 ?m spectral range) consisting of a short (50?80 ?m) cleaved laser and a short (30?80 ?m) external air resonator with a high-reflectivity mirror. The SCC laser resonator combines the advantages of both a short-cavity laser and a coupled-cavity laser for effective mode selection. Single-mode operation has been maintained at modulation rates of 2 Gbit/s.     

Megahertz linewidth from a 1.5 ?m semiconductor laser with HeNe laser injection

The linewidth of a 1.5 ?m semiconductor laser has been reduced from > 1 GHz to < 1.5 MHz by injection locking the laser to the low-power narrow-linewidth output from an HeNe laser operating at 1.523 ?m. A collimated-beam power of 750 ?W was obtained in the injection-locked semiconductor laser mode.     

Er3+:Yb3+:GdAl3(BO3)4晶体1.5～1.6 μm波段激光性能

采用熔盐法获得了Yb3 和Er3 离子原子数分数分别为20%和1.1%的GdAl3(BO3)4(简称GAB)晶体.在平-凹谐振腔中,利用0.97μm波长光纤耦合准连续(CW)半导体激光端面抽运0.7 mm厚的该晶体,当输出镜透过率为1.5%时,获得斜率效率为20%,最高功率为1.75 W的1.5~1.6μm波段激光输出.输出激光波长随吸收抽运功率和输出镜透过率发生变化.当输出镜透过率为1.5%时,随着吸收抽运功率的增加,不仅起振的纵模带增加并且输出功率逐渐从1.60μm的纵模带中转移到1.55μm的纵模带中.而当吸收抽运功率为13.6 W时,随着输出镜透过率的增加,输出激光波长从1.60μm转移到1.52μm.结果表明Er3 和Yb3 双掺的GAB晶体是一种优秀的1.5~1.6μm波段激光材料.     

Efficient generation of near-i.r. stimulated light scattering in optical fibres pumped in low-dispersion region at 1.3 ?m

By pumping a low-loss single-mode fibre in the low-dispersion wavelength region with a 1.3 ?m Q-switched Nd:y.a.g. laser, efficient near-i.r. (1.15?1.6 ?m) stimulated light scattering has been obtained. The peak wavelength for the stimulated Raman emission is found to be fibre-length dependent, and the threshold pump power is as low as 10 W, when coupled into a 150 m fibre.     

Mode attenuation at 1.39 ?m in graded-index fibres

The differential mode attenuation ?m(?) in the spectral region of OH absorption (1.2?1.6 ?m) has been studied in SiO2/GeO2 core graded-index fibres. It was found that the mode attenuation due to OH absorption Km(?) at 1.39 ?m had its maximum in the fibre core centre. The comparison between the calculated and measured Km(?) at this wavelength could be used for the determination of OH-ion distribution profile in optical fibres.     

Linewidth of a single mode in a multimode injection laser

An expression is derived for the quantum noise-limited line-width of each individual mode in a multimode laser. Numerical calculations show that the mode linewidth of a two-mode 1.55 ?m laser is only about 10% larger than that in a single-mode device.     

基于多模光纤偏振烧孔效应的双波长掺铒光纤激光器

基于多模光纤(MMF)引入的偏振烧孔(PHB)效应,研制了一种环形双波长掺铒光纤(EDF)激光器.单模光纤(SMF)-MMF-SMF组成的结构使MMF不同偏振方向的反射模在波长上分开,利用PHB效应实现双波长的输出,输出波长间隔可通过改变MMF的长度改变.实验对比了1.6 m和3.0 m长的MMF输出波谱特性,结果表明...     

Single-mode semiconductor laser optically pumped by an injection laser

Nanosecond pulses from an AlGaAs injection laser have been used to optically pump an ultrashort-cavity InP laser. Subnanosecond pulses from the InP laser exhibit a single longitudinal mode at 0.92?0.93 ?m.     

Transmission performance impairment due to degradation of optical spectrum in 1.55 ?m DFB laser

The dynamic optical spectrum and optical transmission characteristics of a 1.55 ?m conventional distributed feedback (DFB) laser with a side mode were analysed. The laser used in the experiment came to operate in two modes although initially it had operated in single-mode. When this laser was directly modulated by setting the bias current around the threshold, the mode switching between a main mode and a side mode was observed to be similar to mode partitioning in Fabry-Perot (FP) lasers. The mode switching affects considerably the bit error rate performance of 113 km single-mode fibre transmission at 140 Mbit/s.     

370 mW, 1.06 ?m, CW TEM00 output from an Nd:YAG laser rod end-pumped by a monolithic diode array

We report 370 mW CW output at 1.06 ?m in the TEM? mode with 9.1% electrical to optical (wall-plug) conversion efficiency from an Nd:YAG laser rod end-pumped by a monolithic 100 ?m-wide diode laser array.     

Chirped picosecond injection laser pulse transmission in single-mode fibres in the minimum chromatic dispersion region

We report the propagation of chirped picosecond InGaAsP injection laser pulses in single-mode fibres in the minimum chromatic dispersion wavelength region. The observed initial compression and subsequent broadening are in good agreement with theory and illustrate the implications of chirped pulse transmission for high-bandwidth communication in the 1.2?1.6 ?m wavelength region.     

1.3 ?m-wavelength mode controlled GaInAsP/InP etched laser

A mode controlled GaInAsP/InP (?=1.3 ?m) etched laser with a lens-like narrow strip waveguide along the <01> direction has been fabricated. The minimum threshold current was 160 mA for 170 ?m cavity length, and a single longitudinal mode operation has been obtained up to 1.3 times the threshold.     

1.6 Gbit/s optical receiver at 1.3 ?m with SAW timing retrieval circuit

The performance of a 1.6 Gbit/s optical receiver employing a s.a.w. filter as a timing tank is reported. The error-rate characteristics in a p.c.m. transmission system using a 1.3 ?m In-GaAsP laser and single-mode fibres were studied. The average received optical power at a 10?9 error rate was ?28 dBm. In a 15 km transmission experiment, the receiving level was degraded by 2 dB owing to fibre dispersion. Timing phase margin of 75 degrees after 12 km transmission was confined with the self-timed receiver.     

High-speed modulation characteristics of a GaSb/AlGaSb multiquantum-well laser diode

The high-speed modulation characteristics of a GaSb/AIGaSb multiquantum-well laser diode (? = 1.66?m) are investigated. The longitudinal mode spectra over 1GHz modulation with quasi-single-mode and small frequency `chirping? were confirmed.     

Lasing characteristics of improved GaInAsP/InP surface emitting injection lasers

The letter presents a surface-emitting GaInAsP/InP injection laser with 7 ?m cavity length operating at 1.30 ?m of wavelength. The threshold was as low as 50 mA at 77 K. The device operated up to 140 K with one single longitudinal mode and small wavelength change (0.64 ?/degree). The near-field diameter was 9 ?m and the far-field angle (FWHM) was 9°. The polarisation was linear.     

1.55 ?m multisection ridge lasers

A new 1.55 ?m wavelength GaInAsP laser is described: the multisection ridge laser. Pulsed thresholds were typically 40?80 mA. CW thresholds were comparable. The lowest measured CW threshold was 38 mA at 12°C. The laser operated stably in a single longitudinal mode (spurious modes down by ?16 dB) under fast pulse modulation with a prebias below threshold. Theoretical results based on a waveguide scattering theory are in qualitative agreement with the experimental results.     

Planar stripe with waist/notch (swan) injection laser

This letter describes a novel planar stripe-geometry injection laser (termed the Swan laser), showing a single transverse and longitudinal mode operation, made by a simple fabrication method. This stripe geometry is composed of a main stripe section with a width of ?10 ?m and a mode-control section with a nominal width near the carrier diffusion length less than 5 ?m; the shape looks like a waist/notch along the stripe. The kink of the light output does not appear at a power level of more than 20 mW/facet.     

Fabrication and performance of 1.5?m GaInAsP travelling-wave laser amplifiers with angled facets

A broadband 1.5?m GaInAsP travelling-wave laser ampli-fier has been realised with angled facets instead of anti-reflection coatings. The measured signal gain for the TE mode is 19dB at the wavelength around 1.49?m with a 2dB gain ripple over one free spectral range and a 3dB band-width of 55 nm. The estimated residual modal reflectivity is 0.2%.     

Modulation characteristics of 1.3 ?m buried-stripe InGaAsP laser up to 2 Gbit/s data rates

Modulation experimenting on a buried-stripe (b.s.) InGaAsP laser emitting at 1.3 ?m was carried out up to 2 Gbit/s. The b.s. laser is free from relaxation oscillation, which degrades modulated optical pube waveforms, especially at high data rates. The repeater gain of 1.6 Gbit/s transmission systems is improved by 9 dB compared with previously reported experiments. Modulation characteristics up to 2 Gbit/s are reported.