Athermal all-polymer arrayed-waveguide grating multiplexer

An athermal arrayed-waveguide grating (AWG) multiplexer relying on an all-polymer approach is reported. The all-polymer AWG consisting of polymer waveguides fabricated on a polymer substrate exhibits excellent performance. By properly adjusting the coefficient of thermal expansion of the polymer substrate, athermal and polarisation-independent AWG devices featuring a wavelength shift of less than ±0.05 nm in the 25-65°C temperature range could be demonstrated     

Athermal silica-based arrayed-waveguide grating multiplexer

A temperature dependent channel wavelength shift in a silica-based arrayed-waveguide grating multiplexer is successfully suppressed from 0.95 to 0.05 nm in the 0-85°C temperature range, which means that it can be used in practical WDM systems without the need for temperature control     

10 GHz-spaced arrayed-waveguide grating multiplexer withphase-error-compensating thin-film heaters

An arrayed-waveguide grating multiplexer with thin-film heaters is fabricated to compensate for phase errors in arrayed waveguides. The phase errors are measured by Fourier transform spectroscopy with a low-coherence interferometer and are used as a monitor when we adjust the phases by controlling thin-film heaters. A channel crosstalk of -25 dB and a loss of 4.2 dB are achieved in a 5×5 10 GHz-spaced multiplexer     

Flat spectral response arrayed-waveguide grating multiplexer withparabolic waveguide horns

An eight-channel flat spectral response arrayed-waveguide grating multiplexer with parabolic waveguide horns has been fabricated on a planar lightwave circuit (PLC). A double-peaked intensity distribution is formed at the slab interface by the parabolic waveguide horn. A 1 dB bandwidth of 98 GHz, 3 dB bandwidth of 124 GHz and 20 dB bandwidth of 196 GHz are obtained for 200 GHz channel spacing. The crosstalk to neighbouring channels is less than -27 dB and the on-chip insertion losses range from 6.1 to 6.4 dB, respectively     

Crosstalk reduction in arrayed-waveguide grating multiplexer/demultiplexer using cascade connection

This paper proposes a cascade-connected arrayed-waveguide grating (AWG) as a solution to the problem of crosstalk accumulation in a large-scale AWG multiplexer/demultiplexer (MUX/DEMUX) and demonstrates a 64-channel cascaded AWG module with a very low background crosstalk of less than -80 dB and a total crosstalk of about -34 dB. In this paper, the authors densely integrate 64 additional compactly designed crosstalk-suppressing AWGs whose bandwidths were carefully optimized and directly attach them to a conventional 64-channel AWG. Consequently, in addition to a very low crosstalk, a low insertion loss and a compact size without passband shape distortion are achieved with this module. Based on the performance of the cascaded AWG module, it is then estimated that it is possible to realize a 1000-channel AWG MUX/DEMUX that is free from the problem of crosstalk accumulation.     

Polarisation-insensitive arrayed-waveguide grating multiplexer withSiO2-on-SiO2 structure

An arrayed-waveguide grating multiplexer with SiO₂-on-SiO₂ structure is fabricated in order to achieve polarisation insensitivity. A negligible wavelength response dependence on polarisation of 0.01 nm, which corresponds to a birefringence of-9×10^-6, is realised in a 16 channel arrayed-waveguide grating multiplexer with a wavelength spacing of 0.8 nm     

Impact of crosstalk in an arrayed-waveguide multiplexer onN×N optical interconnection

The impact of crosstalk in an arrayed-waveguide N×N wavelength multiplexer is investigated precisely in relation to its application to wavelength-routing N×N all optical networks. In such systems multiple crosstalk light which has the same wavelength as the signal results in signal-crosstalk beat noise. We confirm that the noise is Gaussian and obtain the relation between crosstalk and power penalty. It is shown that the crosstalk must be less than -38 dB for a 16×16 system to keep the power penalty below 1 dB at a bit error rate of 10^-9     

Wavelength multiplexer based onSiO2-Ta2O5 arrayed-waveguide grating

The characteristics of a wavelength multiplexer based on an arrayed-waveguide grating are carefully investigated by using the grating theory and related experiments. A 28-channel multiplexer is designed and fabricated as SiO₂-Ta₂O₅ waveguides on a 1 cm×2 cm substrate. The designed wavelength channel spacing of 1 nm is obtained. The crosstalk to an adjacent channel is -15 dB. The measured minimum loss is 4.2 dB, which is composed of 3.4 dB excess loss and 0.8 dB grating loss     

阵列波导光栅器件的发展与应用

密集波分复用（ＤＷＤＭ）是光纤通信中的关键技术,而阵列波导光栅（ＡＷＧ）在波分复用系统中有 广泛的应用。本文综述了ＡＷＧ的原理以及它的发展和光纤通信系统中的应用。     

Anticrosstalk arrayed-waveguide add-drop multiplexer with foldbackpaths for penalty free transmission

A novel optical add-drop multiplexer based on an arrayed-waveguide wavelength multiplexer is proposed. The foldback configuration is employed to avoid the bit error rate degradation caused by the light crosstalk common in arrayed-waveguide multiplexers. Penalty free transmission is demonstrated     

硅基二氧化硅阵列波导光栅的研究进展

阵列波导光栅（ Ａ Ｗ Ｇ） 是（ 密集） 波分复用技术的关键器件之一。提高 Ａ Ｗ Ｇ 器件的性能和拓展 Ａ Ｗ Ｇ 器件的功能是 Ａ Ｗ Ｇ 器件发展的两大方向。综述了 Ａ Ｗ Ｇ 的串扰、波长响应展宽和偏振特性的优化措施,以及以 Ａ Ｗ Ｇ 为基本器件构成的多种功能模块,如１６ 路上路／ 下路复用器、多波长环形激光器等     

Reflective arrayed waveguide grating multiplexer

A high-performance reflective arrayed waveguide grating multiplexer/demultiplexer designed for compatibility with silicon integrated circuit processing is described. The grating, folded by a flat reflecting surface, can be printed in a single-exposure field of a photolithographic stepper. Advanced plasma assisted deposition is used to prepare waveguides with very low loss and minimum birefringence. Multiplexers with 40 channels separated by 100 GHz show intrinsic insertion losses of -2.4 dB, channel uniformity less than 0.6 dB, and very low polarization dependent wavelength shift of 0.012 nm.     

Eight-channel flat spectral response arrayed-waveguide multiplexer with asymmetrical Mach-Zehnder filters

An eight-channel flat spectral response arrayed-waveguide grating (AWG) multiplexer with asymmetrical Mach-Zehnder filters has been fabricated on the planar lightwave circuit (PLC). The monotonic spectral loss characteristics of AWG have been canceled by the opposite spectral response in the asymmetric MZ filter. The 1.5 dB bandwidth of 141 GHz and 3 dB bandwidth of 159 GHz are obtained for the 200 GHz channel spacing. The 1.5 dB bandwidth becomes 1.8 times wider than that of the conventional AWG. Crosstalks to neighboring and all other channels are less than -24 dB and the on-chip insertion losses range from 7.0 to 7.4 dB, respectively.     

Planar 1 × N optical multiplexer with nearly ideal response

It is shown that nearly ideal multiplexing and demultiplexing can be realized in optical networks by using a planar arrangement of two waveguide gratings combined with a reflector (or a waveguide lens). The new arrangement, realized by using a new type of waveguide array, implies higher spectral efficiency and higher capacity for future optical networks     

Impact of crosstalk in an arrayed-waveguide router on an opticaladd-drop multiplexer

The impact of crosstalk in an arrayed-waveguide (AWG) router on the performance of an N-channel optical add-drop multiplexer (OADM), with m add/drop channels and n-pass channels is theoretically investigated. A single arrayed-waveguide router is simultaneously used for multiplexing and demultiplexing. This results in crosstalk not only from the incoming channels, but from the outgoing channels as well. We show that the performance of the OADM degrades as either N or m are increased, suggesting that the number of channels in a network based on OADM's is limited by crosstalk in the AWG router. When an optical filter is added at the output of the OADM the digital signal-to-noise ratio Q is independent of N and m, and within a few tenths of a decibel of the perfect filtering case     

A novel fabrication approach for an athermal arrayed-waveguide grating

A novel method for fabricating an athermal AWG is proposed, using a unique apparatus for ITU-T center wavelength adjustment and optical coupling of two cut-parts. UV adhesive or sticky gel is applied into the gap between the cut-elements and the alignment base substrate by capillary infiltration. The spectrum profiles are almost the same as those of the original chip state, and no deterioration is observed resulting from athermalization. Flat-top athermal AWG modules of 100 GHz×40 ch are fabricated. Over a temperature range of-40 to 85℃, the center wavelength shift is±22 pm, and the insertion loss change is less than ±0.11 dB.     

Performance of multiwavelength simultaneous monitoring circuitemploying arrayed-waveguide grating

This paper proposes a novel multiwavelength simultaneous monitoring (MSM) circuit that uses the wavelength crossover properties of an arrayed-waveguide grating (AWG). The MSM circuit consists of an AWG, a stabilized semiconductor laser as a reference light, and logarithmic amplifiers. The AWG chip is a simple planar-lightwave-circuit chip. It functions as multiple optical filters, and make it possible to monitor multiple wavelengths simultaneously. The MSM circuit, locked to the reference wavelength produced by a semiconductor laser stabilized to the 1547.49 mn ¹³C₂ H₂ absorption line, achieved 10 MHz resolution and 30 MHz stability for 24 h in the stable polarization state. Measurement accuracy of better than 1.1 GHz can be realized even if the state of polarization of the input light fluctuates at random. Multiwavelength simultaneous monitoring is successfully demonstrated using tunable lasers     

Demonstration of a 15×15 arrayed waveguide multiplexer on InP

By interconnecting two star couplers with a waveguide grating, the authors built a monolithic 15×15 multiplexer on InP. The grating order of 148 gives a free spectral range of 10.5 nm (1.3 THz) and a channel spacing of 0.7 nm (87 GHz) at 1550 nm wavelength. A crosstalk between adjacent channels of less than 18 dB and a residual crosstalk of less than 25 dB were obtained. The on-chip insertion loss is typically 2-4 dB     

Low-loss arrayed-waveguide grating with high index regions atslab-to-array interface

A novel structure is proposed to reduce the transition loss of an arrayed-waveguide grating. The structure comprises high refractive-index regions formed at the core of slab waveguides in the vicinity of an array with ultraviolet (UV) irradiation. The insertion loss was reduced by 3.0 dB after UV irradiation. The minimum insertion loss became 2.1 dB, which includes fibre-to-chip loss of ~0.8 dB     

Second- and third-order dispersion compensator using ahigh-resolution arrayed-waveguide grating

We have proposed a dispersion compensation scheme that uses a high-resolution arrayed-waveguide grating (AWG). When the diffraction order of the AWG is 59 and the number of waveguides in an arrayed-waveguide is 340, the calculated maximum second- and third-order dispersion compensation range is 18.0 ps/nm and ±6.0 ps/nm² , and 1100 ps/nm and ±937.5 ps/nm², for a 1 ps-pulse and a 12.5 ps-pulse, respectively. In experiments, second-order dispersion (-0.8 to +5.2 ps/nm) is effectively compensated for 1,1-ps pulses; and. Pulse compression by third-order dispersion compensation is successfully demonstrated