Split-step digital backward propagation (DBP) can be combined with coherent detection to compensate for fiber nonlinear impairments. A large number of DBP steps is usually needed for a long-haul fiber system, and th...Split-step digital backward propagation (DBP) can be combined with coherent detection to compensate for fiber nonlinear impairments. A large number of DBP steps is usually needed for a long-haul fiber system, and this creates a heavy computational load. In a trade-off between complexity and performance, interchannel nonlinearity can be disregarded in order to simplify the DBP algorithm. The number of steps can also be reduced at the expense of performance. In periodic dispersion-managed long-haul transmission systems, optical waveform distortion is dominated by chromatic dispersion. As a result, the nonlinearity of the optical signal repeats in every dispersion period. Because of this periodic behavior, DBP of many fiber spans can be folded into one span. Using this distance-folded DBP method, the required computation for a transoceanic transmission system with full inline dispersion compensation can be reduced by up to two orders of magnitude with negligible penalty. The folded DBP method can be modified to compensate for nonlinearity in fiber links with non-zero residua dispersion per span.展开更多
The fibre-optic microwave photonic link has become one of the basic building blocks for microwave photonics.Increasing the optical power at the receiver is the best way to improve all link performance metrics includin...The fibre-optic microwave photonic link has become one of the basic building blocks for microwave photonics.Increasing the optical power at the receiver is the best way to improve all link performance metrics including gain,noise figure and dynamic range.Even though lasers can produce and photodetectors can receive optical powers on the order of a Watt or more,the power-handling capability of optical fibres is orders-of-magnitude lower.In this paper,we propose and demonstrate the use of few-mode fibres to bridge this power-handling gap,exploiting their unique features of small acousto-optic effective area,large effective areas of optical modes,as well as orthogonality and walk-off among spatial modes.Using specially designed few-mode fibres,we demonstrate order-of-magnitude improvements in link performances for single-channel and multiplexed transmission.This work represents the first step in few-mode microwave photonics.The spatial degrees of freedom can also offer other functionalities such as large,tunable delays based on modal dispersion and wavelength-independent lossless signal combining,which are indispensable in microwave photonics.展开更多
Non-mode-selective(NMS) multiplexers(muxes) are highly desirable for coherent power combining to produce a high-power beam with a shaped profile(wavefront synthesis) from discrete, phase-locked emitters. We propose a ...Non-mode-selective(NMS) multiplexers(muxes) are highly desirable for coherent power combining to produce a high-power beam with a shaped profile(wavefront synthesis) from discrete, phase-locked emitters. We propose a design for a multi-plane light conversion(MPLC)-based NMS mux, which requires only a few phase masks for coherently combining hundreds of discrete input beams into an output beam consisting of hundreds of Hermite–Gaussian(HG) modes. The combination of HG modes as a base can further construct a beam with arbitrary wavefront. The low number of phase masks is attributed to the identical zero-crossing structure of the Hadamard-coded input arrays and of the output HG modes, enabling the practicality of such devices. An NMS mux supporting 256 HG modes is designed using only seven phase masks, and achieves an insertion loss of-1.6 d B, mode-dependent loss of 4.7 d B, and average total mode crosstalk of-4.4 d B. Additionally, this design,featuring equal power for all input beams, enables phase-only control in coherent power combining, resulting in significant simplifications and fast convergence compared with phase-and-amplitude control.展开更多
Space-division multiplexing(SDM)has attracted significant attention in recent years because larger transmission capacity is enabled by more degrees of freedom(DOFs)in few-mode fibers(FMFs)compared with singlemode fibe...Space-division multiplexing(SDM)has attracted significant attention in recent years because larger transmission capacity is enabled by more degrees of freedom(DOFs)in few-mode fibers(FMFs)compared with singlemode fibers(SMFs).To transmit independent information on spatial modes without or with minor digital signal processing(DSP),weakly-coupled FMFs are preferred in various applications.Several cases with different use of spatial DOFs in weakly-coupled FMFs are demonstrated in this work,including single-mode or mode-groupmultiplexed transmission,and spatial DOFs combined with time or frequency DOF to improve the system performance.展开更多
Recently, space-division multiplexing (SDM) techniques using multi-core fiber (MCF) and few-mode fiber (FMF) have been introduced into optical fiber communication to increase transmission capacity. Two main type...Recently, space-division multiplexing (SDM) techniques using multi-core fiber (MCF) and few-mode fiber (FMF) have been introduced into optical fiber communication to increase transmission capacity. Two main types of optical fiber amplifiers based on the Erbium- doped fiber (EDF) and the Raman effect have been developed to amplify signals in the MCF and FMF. In this paper, we reviewed the principles and configurations of these amplifiers.展开更多
The high-temperature sensitivity of the silicon material index limits the applications of silicon-based micro-ring resonators in integrated photonics. To realize a low but broadband temperature-dependent-wavelength-sh...The high-temperature sensitivity of the silicon material index limits the applications of silicon-based micro-ring resonators in integrated photonics. To realize a low but broadband temperature-dependent-wavelength-shift microring resonator, designing a broadband athermal waveguide becomes a significant task. In this work,we propose a broadband athermal waveguide that shows a low effective thermo-optical coefficient of1 × 10^(-6)∕K from 1400 to 1700 nm. The proposed waveguide shows a low-loss performance and stable broadband athermal property when it is applied to ring resonators, and the bending loss of ring resonators with a radius of >30 μm is 0.02 dB/cm.展开更多
Microresonator-based Kerr frequency combs have attracted a great deal of attention in recent years, in which mode locking of the generated combs is associated with bright or dark cavity soliton formation. In this pape...Microresonator-based Kerr frequency combs have attracted a great deal of attention in recent years, in which mode locking of the generated combs is associated with bright or dark cavity soliton formation. In this paper, we show a unique that, different from soliton propagation along a waveguide, cavity solitons can be robustly formed under dispersion profile with four zero-dispersion wavelengths. More importantly, such a dispersion profile exhibits much smaller overall dispersion, thus making it possible to greatly reduce the pump power by five to six times.展开更多
Space-division multiplexing (SDM) using multi-core fibers (MCFs) and few-mode fibers (FMFs) was proposed as a solution to increase capacity and/or reduce the cost per bit of fiber-optic transmission. Advances in...Space-division multiplexing (SDM) using multi-core fibers (MCFs) and few-mode fibers (FMFs) was proposed as a solution to increase capacity and/or reduce the cost per bit of fiber-optic transmission. Advances in passive and active SDM devices as well as digital signal processing have led to impressive SDM transmission demonstrations in the laboratory. Although the perceived advantages in terms of capacity and cost per bit that SDM offers over parallel SMF bundles are not universally accepted, SDM is beginning to emerge as an indispensable solution in major network segments. The introduction of the spatial degree of freedom allows optical networks to overcome fundamental limitations such as fiber nonlinearity as well practical limitations such as power delivery. We describe these application scenarios that the optical communications industry has already began to explore. From a fundamental science point of view, concepts such as the principal modes, generalized Stokes space, and multi-component solitons discovered in SDM research will likely have a broad impact in other areas of science and engineering.展开更多
Light propagation in random media is a subject of interest to the optics community at large,with applications ranging from imaging to communication and sensing.However,real-time characterization of wavefront distortio...Light propagation in random media is a subject of interest to the optics community at large,with applications ranging from imaging to communication and sensing.However,real-time characterization of wavefront distortion in random media remains a major challenge.Compounding the difficulties,for many applications such as imaging(e.g.,endoscopy)and focusing through random media,we only have single-ended access.In this work,we propose to represent wavefronts as superpositions of spatial modes.Within this framework,random media can be represented as a coupled multimode transmission channel.Once the distributed coherent transfer matrix of the channel is characterized,wavefront distortions along the path can be obtained.Fortunately,backreflections almost always accompany mode coupling and wavefront distortions.Therefore,we further propose to utilize backreflections to perform single-ended characterization of the coherent transfer matrix.We first develop the general framework for single-ended characterization of the coherent transfer matrix of coupled multimode transmission channels.Then,we apply this framework to the case of a two-mode channel,a single-mode fiber,which supports two randomly coupled polarization modes,to provide a proof-of-concept demonstration.Furthermore,as one of the main applications of coherent channel estimation,a polarization imaging system through singlemode fibers is implemented.We envision that the proposed method can be applied to both guided and free-space channels with a multitude of applications.展开更多
We propose a mode demultiplexing hybrid(MDH) that integrates mode demultiplexing, local oscillator power splitting, and optical 90-deg mixing using multi-plane light conversion(MPLC). We demonstrate the realization of...We propose a mode demultiplexing hybrid(MDH) that integrates mode demultiplexing, local oscillator power splitting, and optical 90-deg mixing using multi-plane light conversion(MPLC). We demonstrate the realization of a three-mode MDH using four phase plates, one more than what is required for an MPLC-based mode demultiplexer, via numerical simulations. The performance of the three-mode MDH is comparable to that of commercial single-mode 90-deg hybrids. This multiple-functionality device enables simplification of the coherent optical front end of mode-division multiplexing receivers.展开更多
A series of new double perovskite LaEuCaSnO(0≤x≤0.8)red phosphors were synthesized by traditional solid-state reaction.The phase,micro structure,photoluminescence(PL)properties,quantum efficiency,and thermal stabili...A series of new double perovskite LaEuCaSnO(0≤x≤0.8)red phosphors were synthesized by traditional solid-state reaction.The phase,micro structure,photoluminescence(PL)properties,quantum efficiency,and thermal stability of the phosphors were investigated.LaCaSnOmatrix has a monoclinic double perovskite structure with space group P2/n.Under near-ultraviolet(UV)light at395 nm,LaEuCaSnOphosphors exhibit the most typical red emission peak at 614 nm,which corresponds to~5 D→~7 Felectric dipole transition of Eu.The optimum Eudoping content is attained at x=0.5,and the LaEuCaSnOphosphor shows a moderate quantum efficiency(32.3%)and high color purity(92.2%).Besides,the temperature-dependent spectrum of the phosphor was studied.The emission intensity of Euat 423 K decreases to 70.94%of the initial intensity at 303 K,and the activation energyΔE is estimated to be 0.232 eV,suggesting that the phosphors possess good thermal stability.The fabricated w-LED based on the phosphors has higher Ra(89),lower CCT(4539 K),and better chromaticity coo rdinates(0.371,0.428).These results prove that the Eu-doped LaCaSnOred phosphor has great potential applications in w-LEDs.展开更多
We propose a new type of dispersion flattening technology, which can generate an ultra-flat group velocity dispersion profile with five and six zero-dispersion wavelengths(ZDWs). The dispersion value varies from-0.15 ...We propose a new type of dispersion flattening technology, which can generate an ultra-flat group velocity dispersion profile with five and six zero-dispersion wavelengths(ZDWs). The dispersion value varies from-0.15 to 0.35 ps/(nm·km) from 4 to 8 μm, which to the best of our knowledge is the flattest one reported so far, and the dispersion flatness is improved by more than an order of magnitude. We explain the principle of producing six ZDWs. Mode distribution in this waveguide is made stable over a wide bandwidth. General guidelines to systematically control the dispersion value, sign, and slope are provided, and one can achieve the desired dispersion by properly adjusting the structural parameters. Fabrication tolerance of this waveguide is also examined.展开更多
In this work,a novel MXene-copolymeric molecularly imprinted hydrogel(FMMIH)with temperature/pH dual response and photothermal conversion performance for selective recognition of cis-diol compounds is successfully pre...In this work,a novel MXene-copolymeric molecularly imprinted hydrogel(FMMIH)with temperature/pH dual response and photothermal conversion performance for selective recognition of cis-diol compounds is successfully prepared.Functionalized MXene becomes an important part of the hydrogel’s skeleton by participating in the free radical polymerization reaction.Therefore,FMMIH exhibits improved mechanical properties and great photothermal conversion performance.Furthermore,based on the temperature/pH dual response,FMMIH can realize the controllable capture and release of ginsenoside Rb1 with cis diol structures through dual recognitions of functional groups and geometric space.Under the conditions of pH 8.5 and 25℃,the adsorption capacity of FMMIH is 26.3 mg·g^(-1) and the imprinting factor is 16.4,showing a good imprinting effect.It is worth noting that the volume shrinkage caused by photothermal conversion of the hydrogel is conducive to the elution of template molecules and greatly saves the time of desorption(the desorption efficiency is as high as 89.4%under light conditions for 30 min,which is 3.7 times in dark conditions).These excellent properties make it possible to have broad prospects in many fields such as separation of cis-diol compounds,drug delivery systems,and biosensors.展开更多
Octave-spanning frequency comb generation in microresonators is promising, but strong spectral losses caused by material absorption and mode coupling between two polarizations or mode families can be detrimental. We e...Octave-spanning frequency comb generation in microresonators is promising, but strong spectral losses caused by material absorption and mode coupling between two polarizations or mode families can be detrimental. We examine the impact of the spectral loss and propose robust comb generation with a loss of even 300 dB/cm.Cavity nonlinear dynamics show that a phase change associated with spectral losses can facilitate phase matching and Kerr comb generation. Given this unique capability, we propose a novel architecture of on-chip spectroscopy systems.展开更多
文摘Split-step digital backward propagation (DBP) can be combined with coherent detection to compensate for fiber nonlinear impairments. A large number of DBP steps is usually needed for a long-haul fiber system, and this creates a heavy computational load. In a trade-off between complexity and performance, interchannel nonlinearity can be disregarded in order to simplify the DBP algorithm. The number of steps can also be reduced at the expense of performance. In periodic dispersion-managed long-haul transmission systems, optical waveform distortion is dominated by chromatic dispersion. As a result, the nonlinearity of the optical signal repeats in every dispersion period. Because of this periodic behavior, DBP of many fiber spans can be folded into one span. Using this distance-folded DBP method, the required computation for a transoceanic transmission system with full inline dispersion compensation can be reduced by up to two orders of magnitude with negligible penalty. The folded DBP method can be modified to compensate for nonlinearity in fiber links with non-zero residua dispersion per span.
基金supported in part by the National Basic Research Program of China(973)Project#2014CB340104/3NSFC Projects 61335005,61377076,61575142,61431009 and 61671227+1 种基金the United States Army Research Office grant W911NF-13-1-0283Shandong Provincial Natural Science Foundation(ZR2011FM015).
文摘The fibre-optic microwave photonic link has become one of the basic building blocks for microwave photonics.Increasing the optical power at the receiver is the best way to improve all link performance metrics including gain,noise figure and dynamic range.Even though lasers can produce and photodetectors can receive optical powers on the order of a Watt or more,the power-handling capability of optical fibres is orders-of-magnitude lower.In this paper,we propose and demonstrate the use of few-mode fibres to bridge this power-handling gap,exploiting their unique features of small acousto-optic effective area,large effective areas of optical modes,as well as orthogonality and walk-off among spatial modes.Using specially designed few-mode fibres,we demonstrate order-of-magnitude improvements in link performances for single-channel and multiplexed transmission.This work represents the first step in few-mode microwave photonics.The spatial degrees of freedom can also offer other functionalities such as large,tunable delays based on modal dispersion and wavelength-independent lossless signal combining,which are indispensable in microwave photonics.
基金Army Research Office(W911NF1710553,W911NF1810365,W911NF1910385)National Science Foundation(1932858,ECCS1808976)Office of Naval Research(N00014202441)。
文摘Non-mode-selective(NMS) multiplexers(muxes) are highly desirable for coherent power combining to produce a high-power beam with a shaped profile(wavefront synthesis) from discrete, phase-locked emitters. We propose a design for a multi-plane light conversion(MPLC)-based NMS mux, which requires only a few phase masks for coherently combining hundreds of discrete input beams into an output beam consisting of hundreds of Hermite–Gaussian(HG) modes. The combination of HG modes as a base can further construct a beam with arbitrary wavefront. The low number of phase masks is attributed to the identical zero-crossing structure of the Hadamard-coded input arrays and of the output HG modes, enabling the practicality of such devices. An NMS mux supporting 256 HG modes is designed using only seven phase masks, and achieves an insertion loss of-1.6 d B, mode-dependent loss of 4.7 d B, and average total mode crosstalk of-4.4 d B. Additionally, this design,featuring equal power for all input beams, enables phase-only control in coherent power combining, resulting in significant simplifications and fast convergence compared with phase-and-amplitude control.
文摘Space-division multiplexing(SDM)has attracted significant attention in recent years because larger transmission capacity is enabled by more degrees of freedom(DOFs)in few-mode fibers(FMFs)compared with singlemode fibers(SMFs).To transmit independent information on spatial modes without or with minor digital signal processing(DSP),weakly-coupled FMFs are preferred in various applications.Several cases with different use of spatial DOFs in weakly-coupled FMFs are demonstrated in this work,including single-mode or mode-groupmultiplexed transmission,and spatial DOFs combined with time or frequency DOF to improve the system performance.
文摘Recently, space-division multiplexing (SDM) techniques using multi-core fiber (MCF) and few-mode fiber (FMF) have been introduced into optical fiber communication to increase transmission capacity. Two main types of optical fiber amplifiers based on the Erbium- doped fiber (EDF) and the Raman effect have been developed to amplify signals in the MCF and FMF. In this paper, we reviewed the principles and configurations of these amplifiers.
基金National Basic Research Program of China(973)(2014CB340104/3)National Natural Science Foundation of China(NSFC)(61775164,61335005,61377076,61575142,61431009)Tianjin University
文摘The high-temperature sensitivity of the silicon material index limits the applications of silicon-based micro-ring resonators in integrated photonics. To realize a low but broadband temperature-dependent-wavelength-shift microring resonator, designing a broadband athermal waveguide becomes a significant task. In this work,we propose a broadband athermal waveguide that shows a low effective thermo-optical coefficient of1 × 10^(-6)∕K from 1400 to 1700 nm. The proposed waveguide shows a low-loss performance and stable broadband athermal property when it is applied to ring resonators, and the bending loss of ring resonators with a radius of >30 μm is 0.02 dB/cm.
基金National Basic Research Program of China(973)(2014CB340104/3)National Natural Science Foundation of China(NSFC)(61775164,61335005,61575142,61431009)Advanced Integrated Optoelectronics Facility at the Tianjin University,China
文摘Microresonator-based Kerr frequency combs have attracted a great deal of attention in recent years, in which mode locking of the generated combs is associated with bright or dark cavity soliton formation. In this paper, we show a unique that, different from soliton propagation along a waveguide, cavity solitons can be robustly formed under dispersion profile with four zero-dispersion wavelengths. More importantly, such a dispersion profile exhibits much smaller overall dispersion, thus making it possible to greatly reduce the pump power by five to six times.
基金This work has been supported in part by the National Basic Research Program of China (973) (No. 2014CB340104/1), the National Natural Science Foundation of China (NSFC) (Grant Nos. 61377076, 61307085 and 61431009).
文摘Space-division multiplexing (SDM) using multi-core fibers (MCFs) and few-mode fibers (FMFs) was proposed as a solution to increase capacity and/or reduce the cost per bit of fiber-optic transmission. Advances in passive and active SDM devices as well as digital signal processing have led to impressive SDM transmission demonstrations in the laboratory. Although the perceived advantages in terms of capacity and cost per bit that SDM offers over parallel SMF bundles are not universally accepted, SDM is beginning to emerge as an indispensable solution in major network segments. The introduction of the spatial degree of freedom allows optical networks to overcome fundamental limitations such as fiber nonlinearity as well practical limitations such as power delivery. We describe these application scenarios that the optical communications industry has already began to explore. From a fundamental science point of view, concepts such as the principal modes, generalized Stokes space, and multi-component solitons discovered in SDM research will likely have a broad impact in other areas of science and engineering.
基金National Science Foundation(1932858,ECCS-1808976)Army Research Office(W911NF-17-1055,W911NF2010085)。
文摘Light propagation in random media is a subject of interest to the optics community at large,with applications ranging from imaging to communication and sensing.However,real-time characterization of wavefront distortion in random media remains a major challenge.Compounding the difficulties,for many applications such as imaging(e.g.,endoscopy)and focusing through random media,we only have single-ended access.In this work,we propose to represent wavefronts as superpositions of spatial modes.Within this framework,random media can be represented as a coupled multimode transmission channel.Once the distributed coherent transfer matrix of the channel is characterized,wavefront distortions along the path can be obtained.Fortunately,backreflections almost always accompany mode coupling and wavefront distortions.Therefore,we further propose to utilize backreflections to perform single-ended characterization of the coherent transfer matrix.We first develop the general framework for single-ended characterization of the coherent transfer matrix of coupled multimode transmission channels.Then,we apply this framework to the case of a two-mode channel,a single-mode fiber,which supports two randomly coupled polarization modes,to provide a proof-of-concept demonstration.Furthermore,as one of the main applications of coherent channel estimation,a polarization imaging system through singlemode fibers is implemented.We envision that the proposed method can be applied to both guided and free-space channels with a multitude of applications.
基金Army Research Office(ARO)(W911NF1710500,W911NF1710553)
文摘We propose a mode demultiplexing hybrid(MDH) that integrates mode demultiplexing, local oscillator power splitting, and optical 90-deg mixing using multi-plane light conversion(MPLC). We demonstrate the realization of a three-mode MDH using four phase plates, one more than what is required for an MPLC-based mode demultiplexer, via numerical simulations. The performance of the three-mode MDH is comparable to that of commercial single-mode 90-deg hybrids. This multiple-functionality device enables simplification of the coherent optical front end of mode-division multiplexing receivers.
基金Project supported by the National Natural Science Foundation of China(61974114)。
文摘A series of new double perovskite LaEuCaSnO(0≤x≤0.8)red phosphors were synthesized by traditional solid-state reaction.The phase,micro structure,photoluminescence(PL)properties,quantum efficiency,and thermal stability of the phosphors were investigated.LaCaSnOmatrix has a monoclinic double perovskite structure with space group P2/n.Under near-ultraviolet(UV)light at395 nm,LaEuCaSnOphosphors exhibit the most typical red emission peak at 614 nm,which corresponds to~5 D→~7 Felectric dipole transition of Eu.The optimum Eudoping content is attained at x=0.5,and the LaEuCaSnOphosphor shows a moderate quantum efficiency(32.3%)and high color purity(92.2%).Besides,the temperature-dependent spectrum of the phosphor was studied.The emission intensity of Euat 423 K decreases to 70.94%of the initial intensity at 303 K,and the activation energyΔE is estimated to be 0.232 eV,suggesting that the phosphors possess good thermal stability.The fabricated w-LED based on the phosphors has higher Ra(89),lower CCT(4539 K),and better chromaticity coo rdinates(0.371,0.428).These results prove that the Eu-doped LaCaSnOred phosphor has great potential applications in w-LEDs.
基金National Natural Science Foundation of China(61775164,61225005,61775165)
文摘We propose a new type of dispersion flattening technology, which can generate an ultra-flat group velocity dispersion profile with five and six zero-dispersion wavelengths(ZDWs). The dispersion value varies from-0.15 to 0.35 ps/(nm·km) from 4 to 8 μm, which to the best of our knowledge is the flattest one reported so far, and the dispersion flatness is improved by more than an order of magnitude. We explain the principle of producing six ZDWs. Mode distribution in this waveguide is made stable over a wide bandwidth. General guidelines to systematically control the dispersion value, sign, and slope are provided, and one can achieve the desired dispersion by properly adjusting the structural parameters. Fabrication tolerance of this waveguide is also examined.
基金the National Natural Science Foundation of China(No.21978024)Beijing Natural Science Foundation(No.2202034)the National Key R&D Program of China(No.2019YFB1309703).
文摘In this work,a novel MXene-copolymeric molecularly imprinted hydrogel(FMMIH)with temperature/pH dual response and photothermal conversion performance for selective recognition of cis-diol compounds is successfully prepared.Functionalized MXene becomes an important part of the hydrogel’s skeleton by participating in the free radical polymerization reaction.Therefore,FMMIH exhibits improved mechanical properties and great photothermal conversion performance.Furthermore,based on the temperature/pH dual response,FMMIH can realize the controllable capture and release of ginsenoside Rb1 with cis diol structures through dual recognitions of functional groups and geometric space.Under the conditions of pH 8.5 and 25℃,the adsorption capacity of FMMIH is 26.3 mg·g^(-1) and the imprinting factor is 16.4,showing a good imprinting effect.It is worth noting that the volume shrinkage caused by photothermal conversion of the hydrogel is conducive to the elution of template molecules and greatly saves the time of desorption(the desorption efficiency is as high as 89.4%under light conditions for 30 min,which is 3.7 times in dark conditions).These excellent properties make it possible to have broad prospects in many fields such as separation of cis-diol compounds,drug delivery systems,and biosensors.
基金National Basic Research Program of China(973)(2014CB340104/3,61775164,61335005,61377076,61575142,61431009)Advanced Integrated Optoelectronics Facility at the Tianjin University
文摘Octave-spanning frequency comb generation in microresonators is promising, but strong spectral losses caused by material absorption and mode coupling between two polarizations or mode families can be detrimental. We examine the impact of the spectral loss and propose robust comb generation with a loss of even 300 dB/cm.Cavity nonlinear dynamics show that a phase change associated with spectral losses can facilitate phase matching and Kerr comb generation. Given this unique capability, we propose a novel architecture of on-chip spectroscopy systems.