Signals Of Different Wavelengths Research Articles

A Tandem Approach to Fabricate a Hybrid, Organic‐Add‐Drop Filter Using Single‐Crystal Disk‐Resonators and Pseudo‐Plastic Crystal Waveguides

AbstractThe progress of photonic integrated circuits (PICs) and related nanophotonic technologies is greatly influenced by precise and complex circuit fabrication know‐how. The integration of chemically different, multiple optical components for constructing hybrid PICs is a tedious and costly affair. Herein, a novel approach to construct a key optical circuit component is reported, namely a hybrid organic add‐drop filter (HOADF) by tandem use of two different techniques, namely, mechanophotonics (micromechanical manipulation) and crystal photonics foundry (focused ion beam, FIB‐assisted crystal milling). The successful integration of FIB‐milled, yellow‐emissive, perylene disk resonators (DRs) to two chemically different pseudo‐plastic microcrystal waveguides, namely yellow–orange‐emitting (Z)−2‐(3,5‐bis(trifluoromethyl)phenyl)−3‐(7‐methoxybenzo[c][1,2,5]thiadiazol‐4‐yl)acrylonitrile (BTD2CF3) and green‐emitting (E)−1‐(((5‐bromopyridin‐2‐yl)imino)methyl)naphthalen‐2‐ol (BPyIN), provides a three‐component HOADF. The fabricated HOADF produce, split, route light signals of different wavelengths in a controlled fashion as anticipated from the circuit geometry. This presented innovative technique has the potential to enable bulk‐scale manufacturing of industrial standard organic PICs.

Measurement of stress-induced sympathetic nervous activity using multi-wavelength PPG

The onset of stress triggers sympathetic arousal (SA), which causes detectable changes to physiological parameters such as heart rate, blood pressure, dilation of the pupils and sweat release. The objective quantification of SA has tremendous potential to prevent and manage psychological disorders. Photoplethysmography (PPG), a non-invasive method to measure skin blood flow changes, has been used to estimate SA indirectly. However, the impact of various wavelengths of the PPG signal has not been investigated for estimating SA. In this study, we explore the feasibility of using various statistical and nonlinear features derived from peak-to-peak (AC) values of PPG signals of different wavelengths (green, blue, infrared and red) to estimate stress-induced changes in SA and compare their performances. The impact of two physical stressors: and Hand Grip are studied on 32 healthy individuals. Linear (Mean, s.d.) and nonlinear (Katz, Petrosian, Higuchi, SampEn, TotalSampEn) features are extracted from the PPG signal’s AC amplitudes to identify the onset, continuation and recovery phases of those stressors. The results show that the nonlinear features are the most promising in detecting stress-induced sympathetic activity. TotalSampEn feature was capable of detecting stress-induced changes in SA for all wavelengths, whereas other features (Petrosian, AvgSampEn) are significant (AUC ≥ 0.8) only for IR and Red wavelengths. The outcomes of this study can be used to make device design decisions as well as develop stress detection algorithms.

A Transponder Aggregator With Efficient Use of Filtering Function for Transponder Noise Suppression

Colorless, directionless, and contentionless reconfigurable optical add/drop multiplexing (CDC-ROADM) provides highly flexible physical layer network configuration. Such CDC-ROADM must operate in multiple wavelength bands which are being increasingly implemented in optical transmission systems. The operation in C+L bands requires switch devices used in CDC-ROADM to also be capable of multiband operation. Recent studies on wavelength division multiplexing (WDM) systems have pointed out the impact of amplified spontaneous emission (ASE) noise generated by signals of different wavelengths, which causes OSNR degradation. Therefore, it is desirable to filter out the ASE noise from different transponders when multiplexing multiple wavelengths at the transmitter side, especially in a system with non-wavelength selective combiners such as directional couplers and multicast switches. The use of transponder aggregators with filtering functions, such as the M × N wavelength selective switch (WSS), is preferable for this filtering. However, the downside of these devices is that it is difficult to provide economical multiband support. Therefore, we propose an economical transponder aggregator configuration by allowing a certain amount of ASE superposition and reducing the number of filtering functions. In this paper, we fabricated a prototype of the proposed transponder aggregator by combining silica-based planar lightwave circuit technology and C+L band WSS, both commercially available, and verified its feasibility through transmission experiments. The novel transponder aggregator is a practical solution for a multiband CDC-ROADM system with improved OSNR performance.

Relationship between Myopia and Light Exposure

Epidemiological studies found that the incidence of myopia was increasing year by year and the age of onset of myopia was showing a trend of affecting increasingly younger children. Reducing the occurrence of myopia and controlling the increase of myopia diopter have always been the focus of research on the prevention and control of myopia. Large randomized controlled clinical trials have found that outdoor activities can effectively reduce the incidence of myopia and delay the progression of myopia. Basic experiments also revealed that there were certain connections between light exposure and myopia. We herein review the research progress, limitations and future directions of research on light exposure and myopia. From the perspective of light properties, increasing the intensity of light can slow the progression of myopia and reduce the occurrence of experimentally induced myopia. However, the actual mechanism of action is still unclear. The rhythmic changes of light exposure caused by the light/dark cycle may cause abnormalities in the secretion of melatonin and dopamine, and changes in the circadian rhythm of intraocular pressure and choroidal thickness, thus affecting myopia. The red light, with relatively longer wavelength and forming images behind the retina, tends to induce myopia more easily, while the blue light, with medium and short wavelength and forming images before the retina, tends to delay myopia progression. However, different species respond differently to lights of different wavelengths, and the relationship between light wavelength and myopia needs further investigation. Future research can be done to further explore the mechanism of action of how light exposure changes the progression of myopia, including the following aspects: how light changes dopamine levels, causing changes in downstream signal pathways, and thus controlling the growth of the axial length of the eye; how retinal photoreceptor cells receive light signals of different wavelengths in order to adjust the refractive power of the eyes; and how to design artificial lighting of reasonable intensity, composition and properties, and apply the design in myopia prevention and control.

A bidirectional hybrid WDM-OFDM network for multiservice communication employing self-injection locked Qdash laser source based on elimination of Rayleigh backscattering noise technique

A scheme for transportation of information with minimum Rayleigh backscattering (RB) noise to the multi-users by employing Qdash laser diode as a source is designed and evaluated. In this paper, employing digital phase shift keying, millimeter wave, 16-quadrature amplitude modulation orthogonal frequency division multiplexing (16-QAM OFDM), and 32-QAM OFDM techniques, the data rates of 4 × 10 Gbps are transmitted simultaneously over 50 km single mode fiber, plus 15 m wireless link, 50 m free space optical (FSO) link, 10 m wireless respectively. Four selective self-injection locked modes of Qdash laser are utilized as optical carriers for downstream and upstream transmission. To ensure the matter of mitigation of RB noise, which mainly arises due to the transmission of light-wave of same wavelengths in bidirectional transportation, the carrier signals of different wavelength are used for modulation and remodulation in optical line terminal and optical network unit. Besides being a strong support to increase the tolerance level against RB noise, this architecture is capable to transmit less noisy information wirelessly in radio frequency sensitive areas too. The constancy of the proposed architecture is evaluated by very low power penalty (~ 1.5–1.7 dB, ~ 2.4–2.6 dB, ~ 1.4–1.6 dB, ~ 1.7–1.8 dB for four channels respectively), clear constellation, prominent eye opening, low bit-error-rate (< 10–9 for pseudo random bit sequence data stream and < 3.8 × 10–3 for OFDM signal) and low error vector magnitude (< 12.4% for 16 QAM, < 10% for 32 QAM). Therefore, the proposed architecture could be promising alternative not only due to the scheme for mitigation of RB noise but also be a potent in the field of applications of the communication world to provide less noisy information to the multi-users (wired/wireless/FSO).

Research on Optimization Policy Routing Technology of Optical Fiber Communication Network

With the development of global informatization, information has penetrated into every corner of human society. With the popularization of Internet, the transmission bandwidth of information becomes more and more important. Nowadays, people’s demand and dependence on information are becoming stronger and stronger. It is urgent to expand the capacity of wide area backbone communication network, and the optical network composed of wavelength division multiplexing (WDM) can just take this role. In WDM network, it can transmit multiple optical signals of different wavelengths in one fiber at the same time. WDM has the advantages of large transmission capacity, strong technical adaptability, simple implementation and easy expansion. In addition, WDM optical network can also make full use of the huge bandwidth of optical fiber itself to carry out high-speed transmission. Now, the optical network using WDM technology has become the backbone network of long-distance transmission. This paper studies the optical fiber communication system and analyzes the structure of the optical fiber network. For the optical network, how to find the appropriate routing is a very important technology. After analyzing all kinds of basic routing technologies, this paper proposes a new policy based routing technology, and carries out relevant experiments. The experimental results show that the new routing technology has some advantages compared with the old routing technology.

Light signaling and UV-B-mediated plant growth regulation.

Light plays an important role in plants' growth and development throughout their life cycle. Plants alter their morphological features in response to light cues of varying intensity and quality. Dedicated photoreceptors help plants to perceive light signals of different wavelengths. Activated photoreceptors stimulate the downstream signaling cascades that lead to extensive gene expression changes responsible for physiological and developmental responses. Proteins such as ELONGATED HYPOCOTYL5 (HY5) and CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) act as important factors which modulate light-regulated gene expression, especially during seedling development. These factors function as central regulatory intermediates not only in red, far-red, and blue light pathways but also in the UV-B signaling pathway. UV-B radiation makes up only a minor fraction of sunlight, yet it imparts many positive and negative effects on plant growth. Studies on UV-B perception, signaling, and response in plants has considerably surged in recent times. Plants have developed different strategies to use UV-B as a developmental cue as well as to withstand high doses of UV-B radiation. Plants' responses to UV-B are an integration of its cross-talks with both environmental factors and phytohormones. This review outlines the current developments in light signaling with a major focus on UV-B-mediated plant growth regulation.

Distance estimations in unknown sea underwater conditions by power LED for robotics swarms

The aim of this paper is to measure distances between autonomous underwater vehicles using power LED as light source and photodiode as receiver in unknown light water adsorption conditions. The method is based on the attenuation of the light signal, depending principally on distance and water characteristics. In a previous paper, we proposed the use of a cheap power LED system to support acoustic devices in localization and configuration computation of an underwater robotics swarm. The idea was based on the exchange of light signals of different wavelengths, to reduce the noise, generated by LEDs; the unknown water conditions, affecting the light propagation, required a local measure of the absorption function $$a(\lambda )$$ to obtain the distance between the source and the receiver. To avoid the use of many different wavelength LEDs, we investigated the influence of power and flash duration on the LED spectral emission. Starting from this experience, we are now able to measure distances without the unpractical local measure of the absorption function. In this paper we show as, modifying frequency, we shall be able to measure $$a(\lambda )$$ and, consequently, the distance d.

Broadband quantum memory using electromagnetically induced transparency in atomic medium

ABSTRACTIn this paper, we describe a theoretical design for the realization of a high capacity (bandwidth) atomic quantum memory based on wavelength division multiplexing and electromagnetically induced transparency in adjacently placed 87Rb vapour cells. Magnetic fields produced by Helmholtz coils are used to tailor the atomic energy levels in the vapour cells and hence storage of various probe signals of different wavelengths becomes possible. We give a detailed description of the proposed experimental setup. We have estimated a very high bandwidth of 50 MHz for our design with a delay bandwidth product of approximately 530. Our prototype design is for storing five different wavelength probe pulses which could be extended to larger values in principle.

Biophysics for All: Tools to Introduce Basic Electrophysiology and Optics to Undergraduates

Performing biophysical experiments is often time consuming, even for experts, and requires an extensive background. However, with an intensive three week course, where students with no prerequisites and diverse backgrounds are introduced to electronics, optics, and biochemistry within the framework of ion channels, students have the opportunity to understand and perform biophysics experiments. With morning lectures and the rest of the day devoted to laboratory work, the students, with voltage sources and resistors, begin with basic electronics. By the end of the first week, they advance to building a voltage clamp on a protoboard. Then using an optics kit, students explore the basics of microscopy. As a culmination of these different tools, the students work with a combination of two-electrode voltage clamp and fluorescence microscope setup to investigate macroscopic currents from RNA-injected Xenopus laevis oocytes. Using an improved Dagan two-electrode voltage clamp with capacitive compensation and current clamp, students record ionic and gating currents and action potentials. With the addition of an optical setup, the students record the optical signals. With the exchangeability of the LED and filter cube, the students can obtain optical signals of different wavelengths, giving them a wide range of fluorophores to use. This simple setup integrates electrophysiology and fluorescence microscopy and allows students to correlate electrical signals with structural changes revealed by fluorescence. Allowing students to work with cutting edge tools such as genetically encoded voltage indicators and simultaneous electrophysiological recordings and fluorimetry gives them a rare look at what biophysicists can do on a daily basis. This methodology is the synthesis of the basic electronics, optics, and ion channel physiology all in one experimental setup. Support: NIHGM030376.

Fiber array coupling based multi-spectral streak tube detection imaging method.

The complementary advantages of the multi-spectral technique and streak tube detection imaging technique can enrich target information with high detection accuracy. In this paper, a new multi-spectral streak tube imaging method is proposed. Instead of using a set of receiving systems for each wavelength, i.e., the traditional method, we use different lengths of fiber arrays in our imaging system to produce the time difference between the echo signals of different wavelengths arriving at the detectors. The imaging process is completed by just one set of the receiving system. The contradiction between multiple wavelength information sub-area processing and large depth of field is alleviated, and the high time resolution is ensured. The mathematical model of this simplified system is established, and two simulation experiments are organized. First, the influence of the time difference on the judgment of echo signals is discussed. Second, we simulate the process of detecting and imaging a target using the traditional multi-spectral streak tube detection method and the proposed method. Finally, we compare the three-dimensional images obtained via the two methods. By observation and calculation, we find that the imaging depth of field and time resolution of the proposed method are better than those of the traditional method.

Interferometric imaging using Si3N4 photonic integrated circuits for a SPIDER imager.

This paper reports design, fabrication, and experimental demonstration of a silicon nitride photonic integrated circuit (PIC). The PIC is capable of conducting one-dimensional interferometric imaging with twelve baselines near λ = 1100-1600 nm. The PIC consists of twelve waveguide pairs, each leading to a multi-mode interferometer (MMI) that forms broadband interference fringes or each corresponding pair of the waveguides. Then an 18 channel arrayed waveguide grating (AWG) separates the combined signal into 18 signals of different wavelengths. A total of 103 sets of fringes are collected by the detector array at the output of the PIC. We keep the optical path difference (OPD) of each interferometer baseline to within 1 µm to maximize the visibility of the interference measurement. We also constructed a testbed to utilize the PIC for two-dimension complex visibility measurement with various targets. The experiment shows reconstructed images in good agreement with theoretical predictions.

Wavelength Division Multiplexer Based on Semiconductor Heterostructures Constructed via Nanoarchitectonics.

Obtaining a wavelength division multiplexer (WDM) at the micro/nanometer level is a considerable challenge that holds great potential in optical communication technology owing to the enlarged data-carrying capacity without laying more fibers. Of the progress that has been made in recent years, one of the most promising methods is to fabricate nanoscale pattern on silicon substrate, forcing signals of different wavelength to enter predesigned channels due to the alternant changes in refractive index. However, it is not an easy task to incorporate light sources into these WDM systems, because of the nonradiative characteristics of silicon itself. This study demonstrates a successful integration of laser signal sources and WDM fully with 1D semiconductor structures. Nanowires from II-VI semiconductor serve as both lasing media and low-loss waveguides for signal loading and delivering, respectively. On the basis of the distinct size-dependent cut-off effect, finely tuning the diameters of homojunctions would result in a controllable filtering of confined signal that light, beyond cut-off wavelength, cannot transfer within the narrowed segments any longer. These results pave the way for semiconductor photonic components toward integration.

Rearrangeable and exchangeable optical module with system-on-chip for wearable functional near-infrared spectroscopy system.

.We developed a system-on-chip (SoC)-incorporated light-emitting diode (LED) and avalanche photodiode (APD) modules to improve the usability and flexibility of a fiberless wearable functional near-infrared spectroscopy (fNIRS) system. The SoC has a microprocessing unit and programmable circuits. The time division method and the lock-in method were used for separately detecting signals from different positions and signals of different wavelengths, respectively. Each module autonomously works for this time-divided-lock-in measurement with a high sensitivity for haired regions. By supplying of power and base and data clocks, the LED module emits both 730- and 855-nm wavelengths of light, amplitudes of which are modulated in each lock-in frequency generated from the base clock, and the APD module provides the lock-in detected signals synchronizing with the data clock. The SoC provided many functions, including automatic-power-control of the LED, automatic judgment of detected power level, and automatic-gain-control of the programmable gain amplifier. The number and the arrangement of modules can be adaptively changed by connecting this exchangeable modules in a daisy chain and setting the parameters dependent on the probing position. Therefore, users can configure a variety of arrangements (single- or multidistance combinations) of them with this module-based system.

Heterogeneity analysis of geophysical well-log data using Hilbert–Huang transform

Geophysical well-log data manifest nonlinear behaviour of their respective physical properties of the subsurface layers as a function of depth. Therefore, nonlinear data analysis techniques must be used to understand and characterize the nature of the subsurface lithologies, vis-à-vis their degree of heterogeneity. One such nonlinear technique is the fully data adaptive Hilbert–Huang Transform (HHT), which constitutes two independent techniques, namely, the empirical mode decomposition technique (EMDT) and the Hilbert spectral analysis (HSA). While EMDT facilitates to decompose the well-log data into oscillatory signals of different wavelengths called intrinsic mode functions (IMFs), which represent different frequency characteristics of the signal and which in turn helps to calculate the degree of heterogeneity in the subsurface, the HSA facilitates to determine the instantaneous amplitudes and frequencies of the IMFs, which can be used to characterize the heterogeneity in the signals. In this study, HHT has been applied to gamma-ray log of the thickest limestone reservoir zones of two different wells: Well B and Well C, located in the western offshore basin of India to determine the respective IMFs. The estimated instantaneous amplitudes and frequencies of the derived IMFs by HSA qualitatively suggested well C to be more heterogeneous than well B. By establishing a relationship between the IMF number (m) and its mean wavelength (Im), a heterogeneity index (ρ) associated with subsurface layers was determined using Im=kρm, where ‘k’ is a constant. ρ bears an inverse relation with the heterogeneity of the subsurface. The estimated ρ values confirm our observations from HSA. We attribute the higher degree of heterogeneity in Well C to high average shale volume in the limestone reservoir zone in Well C than in Well B. Interpretation of the results together with those of the heterogeneity analysis of the gas zone in limestone reservoir of Well C is made by comparing with the results of multifractal analysis of the same data carried out earlier.

Dynamic Lightpath Establishment Considering Four‐Wave Mixing for Achieving Low‐Power All‐Optical Networks

SUMMARYThis paper proposes a method for dynamically establishing a lightpath that takes into consideration power consumption and four‐wave mixing (FWM) in an all‐optical network. In an all‐optical network, an optical fiber amplifier is used to amplify a group of optical signals of different wavelengths in a fiber without O/E/O conversion. Even if only one optical signal passes through an optical fiber amplifier in a fiber, the optical fiber amplifier operates. Thus, to efficiently use the power of an optical fiber amplifier, multiple optical signals in the fiber should be simultaneously amplified. FWM is one of the most important physical impediments to be resolved an in all‐optical network because FWM degrades the performance of such networks. The FWM power in a fiber increases with the number of wavelengths used in the fiber. Therefore, in order to reduce the FWM power, it is preferable to have optical signals be transmitted on different fibers. The proposed method provides an ingenious path, wavelength, and fiber selection strategy that takes the trade‐off between power consumption and FWM power into account. Furthermore, the proposed method avoids blocking of lightpath establishment due to depletion of wavelength resources. Through simulation experiments, we show that the proposed method can efficiently reduce the blocking probability, power consumption, and FWM power when the number of fibers is fixed.

The Trichoderma atroviride cryptochrome/photolyase genes regulate the expression of blr1-independent genes both in red and blue light

Quantitative transcriptome analysis led to the identification of 331 transcripts regulated by white light. Evaluation of the response to white light in mutants affected in the previously characterized blue-light receptor Blr1, demonstrated the existence of both Blr1-dependent and independent responses. Functional categorization of the light responsive genes indicated the effect of light on regulation of various transcription factors, regulators of chromatin structure, signaling pathways, genes related to different kinds of stress, metabolism, redox adjustment, and cell cycle among others. In order to establish the participation of other photoreceptors, gene expression was validated in response to different wavelengths. Gene regulation by blue and red light suggests the involvement of several photoreceptors in integrating light signals of different wavelengths in Trichoderma atroviride. Functional analysis of potential blue light photoreceptors suggests that several perception systems for different wavelengths are involved in the response to light. Deletion of cry1, one of the potential photoreceptors, resulted in severe reduction in the photoreactivation capacity of the fungus, as well as a change in gene expression under blue and red light.

A study of 100 Gb/s 2R regeneration for return-to-zero code signal

Quality of optical signal can be severely degraded after a long distance optical fiber transmission, therefore all-optical 2R (re-amplification, re-shaping) regeneration is required for its low power consumption and good potential of high-speed operation. Semiconductor optical amplifier (SOA) is a very promising candidate for regeneration due to its relatively low nonlinear switching power threshold and possibility of integration. However, speeds of the existing 2R schemes based on SOAs are limited by pattern effects introduced by the long carrier recovery time. So far, most of experimental results for SOA-based regeneration schemes have been limited to 40 Gb/s, only a few demonstrations at 80 Gb/s are available. An effective method to cope with the pattern effects in the SOA is to employ cross gain compression (XGC) effect. Simultaneously injecting two signals of different wavelengths with complementary logics and balanced powers into the SOA leads to an almost constant ability to make the XGC effect intrinsically immune to the pattern effects. Previously, 2R experimental results were demonstrated at 10 Gb/s and 40 Gb/s with XGC respectively, but no further results of higher speed have been presented to date. In this study, we improve the previous two-stage configuration for XGC-based regeneration by introducing a transient cross phase modulation (T-XPM) in the first SOA for generating the high-quality logic-inverted signal, which, as we find, is essential to facilitating the high-speed XGC operation in the next SOA. Firstly, a numerical model of the photon-electron dynamics in an SOA is built with considering the ultrafast intra-band processes, amplified spontaneous emission (ASE) noise at multiple wavelengths, and device segmentation along propagation direction. The quality of the logic-inverted signal with different offsets of the filter wavelength for T-XPM is studied with the model. It is found that the appropriate blue-shift detuning of the filter wavelength greatly helps to improve the quality of the logic-inverted signal. In experiment, the influence of the filter offset on the quality of the logic-inverted signal is also investigated systematically and the best quality and the largest eye-opening of the logic-inverted signal are achieved with a blue-shift of 0.72 nm, which are consistent with the simulation result. With the best logic-inverted signal, XGC effect is deployed in the second SOA. Effective reduction of the amplitude fluctuation can be observed by comparing the eye diagrams of the input degraded with output regenerative signals. Bit error rates (BERs) are also measured for all four tributaries of the degraded and the regenerated signals and the receiving sensitivity at a BER of 10-9 is improved by 1.7-2 dB. Such results show that the XGC-based 2R regeneration scheme is effective even at a speed of as high as 100 Gb/s with the help of high-quality logic-inverted signal. Degraded signals at different wavelengths (from 1535 nm to 1555 nm) are successfully regenerated with Q-factor improvement, demonstrating the wavelength-independent regeneration capability of the XGC-based 2R regenerator.

Повышение точности измерения общего количества водяных паров в атмосфере с помощью спектрорадиометра MODIS

Abstract: Upon given assumptions the aerosol error of measurements of total content of water vapors does occur mainly due to utilization in calculations the ratio of measured signals of different wavelengths. It is determined, that utilization of weighted triads of results of measurements at three wavelengts allows to increase the accuracy of measurements by removal of aerosol error.

Dynamic Lightpath Establishment Considering Four-Wave Mixing for Achieving Low Power All-optical Networks

This paper proposes a dynamic lightpath establishment scheme considering power consumption and four-wave mixing (FWM) in all-optical networks. In all-optical networks, an optical amplifier is used to amplify a group of optical signals of different wavelengths in a fiber without O/E/O conversion. Even if only one optical signal passes through an optical amplifier in a fiber, the optical amplifier operates. Thus, to efficiently use power of the optical amplifier, multiple optical signals in the fiber should be simultaneously amplified. FWM is one of the most important physical impairments to be resolved in all-optical networks because FWM decays the performance of all-optical networks. The FWM power in a fiber increases with the number of wavelengths used in the fiber. Therefore, in order to reduce the FWM power, it is preferred that optical signals are transmitted on different fibers. The proposed scheme provides an ingenious route, wavelength, fiber selection strategy considering the tradeoff between the power consumption and the FWM power. Furthermore, the proposed scheme avoids blocking of lightpath establishment due to depletion of wavelength resources. Through simulation experiments, we show that the proposed scheme efficiently reduces the blocking probability, the power consumption, and the FWM power in case of the number of fibers is fixed.