High Power Continuous Wave Fiber Laser System

High Power Continuous Wave Fiber Laser System Introduction of High Power Fiber Laser The optical fiber with very high surface-to-volume ratio and a strong waveguide effect provides the fiber based laser source the potential to generate high power laser beam with high quality. In addition to the capacity of generating raw optical power with high beam quality, the fiber laser system has other appealing features, such as supporting robust and compact system designs, allowing ultrashort pulse operation, offering a board wavelength tunability, and providing high gains. Those features stimulate the research on the high power fiber lasers system, and lay the foundation of novel appealing applications, such as remote material processing, aerospace and defense. In the past decade, a remarkable increase of the powers produced by fiber lasers with high beam quality has been achieved (see Fig.1). As a result, the high power laser becomes strong counterpart of the solid-state bulk laser, and penetrates rapidly into areas that formerly other lasers were used. Literature Review In the early 1960s, the first fiber laser was demonstrated by Snitzer. The doped fibers potential for high optical gain was revealed by David Payne and co-researchers working on Neodymium- doped fibers in mid 1980s . In 2009, the high power fiber laser, which based on a specifically silica-host ytterbium-doped fiber-based laser (YDFL), obtained 10 kW output in the single-mode (SM) regime. Although architectures are different, the high-power fiber lasers and amplifiers are mostly archived with rare-earth-doped (RE-doped) double-clad fibers. The double-clad fiber, which was initially demonstrated in 1988, provided the option of cladding pumping, and proved to be one of the key technologies for power scaling. The structure of this double cladding is that the active RE-doped core is surrounded by a much larger inner cladding (see Fig. 2), and are encircled together by out cladding. The pump beam emitted by fiber-coupled high-power diode bars or other kinds of laser diodes is coupled into the inner cladding, and confined within it by an outer cladding. The confined pump beam will be absorbed into the core while it propagates along the fiber. The laser light is generated in the central core, and the laser light can have very good beam quality even diffraction limited beam. Thereby, by means of double cladding configurations one realized the conversion from low brightness p ump to high brightness single-mode fiber laser output. As the spatial and angular pump acceptance [can be expressed as the product of area and the square of the numerical aperture (NA)] for the inner cladding is significantly improved to the core pump, Such conversion is more effective, and close to 5 orders have been demonstrated experimentally. Among high power RE-doped fiber lasers, the YDFL is notable in term of high power. The Ybs broad absorption band extends from 900 to 980 nm (see fig 3), covering high power pump LDs best performance wavelengths, offers a low quantum defect [energy difference between pump and laser photons] for pumping with 9xx nm LD and lasing above 1040nm. This superior property offers the potential for achieving very high power efficiencies and reducing thermal effects. In addition, lasing at wavelength above 1040nm, the Yd ion shows a simple four level structure, that excludes excited state absorption and also a variety of detrimental quenching processes allowing high doping concentrations, which means high pump absorption per unit length. On the contrary, the small quantum defect also has a usually unwanted consequence: the significant quasi-three-level behavior, especially when lasing at short wavelengths (less then 1040nm), that will cause a high threshold and decrease the power efficiency. Fig. 2. Structure of a double-clad fiber and principle of cladding-pumping The Nd doped laser emitting at 1060 nm is a four-level system, which means a lower laser threshold. Associated with the relatively advanced state of 808 nm diodes for pumping Nd:YAG, this made Nd the choice for high power fiber lasers in early stage. Todays high power pump diodes in 9 xx nm are sufficiently bright to make threshold unimportant for most quasi-three-level high power fiber lasers. These overcome the obstacle of ytterbiums higher threshold and raise advantages of a lower quantum defect and higher doping concentration with quench-free. The first single-mode Yb doped fiber laser with output power over 100 W was demonstrated in 1999 , and it illustrated that the advantages of Yb doped double cladding structure can support for further increase in the average power by scaling the size of the optical fiber and the power of pump diode source. Soon after that, the power of cladding pumped YDFL obtained the kilowatt level. Thereafter, by investigating the large-area core design a nd fabrication, the single-mode operation in kilowatt level was realized that would not have been possible for Nd doping. Figure 3: Absorption and emission cross sections of ytterbium-doped germanosilicate glass, as used in the cores of ytterbium-doped fibers. Another sophisticated technique which is adopted in all double-clad fiber lasers at 3 kW and above, is tandem-pump [in-band pumping with high-brightness pump sources, such as one or several fiber lasers, or thin disk laser]. The tandem pump makes it possible to pump close to the emission wavelength so that the quantum defect heating will be low resulting in a reduced thermal load. Actually, some advanced solid-state lasers, such as thin disk laser, is well matched with requirements of in-band high brightness pumping source, and 1 KW level output thin disk laser pumped fiber laser have been realized. Nonlinearities are an issue to further increase the CW output power of the fiber laser. The fiber laser considered above such as in Fig. 1 has operated with linewidths in the 110 nm range. In such system with cw operating, excepting at the extremely high powers or long delivery fibers, the stimulated Raman scattering (SRS) is a weak effect and is relatively easy to prevent. However, for output power above 10 kW, the Raman gain can become so high (tens of decibels) that a considerable part of the power is transferred to a longer-wavelength Stokes wave, reducing the power in the signal wavelength. There are some applications need single frequency sources which can provide light power with narrower spectral line width, such as coherent beam combination of multiple single frequency fiber sources with high power. This scheme offers a promising method for further power scaling, and consequently this stimulates interest in single-frequency power scaling. For narrow bandwidth, especially at linewidths less than 10 MHz, the SBS is the dominate nonlinearity and the severe obstacle for high power single-frequency fiber sources. The SBS can be suppressed with shorter fiber and larger mode field area, and output power of hundred watts has been reported with such schemes .However, this power is still less comparing with the bulk solid state laser. There are several options for SBS mitigation, including straining the fiber in order to broaden the SBS gain bandwidth, and reducing overlap between the optical and acoustic fields. The highest power high-gain fiber amplifier can archive 1.7KW. It was realized by combination of the modest spectral broadening with phase modulation and the fiber with enlarged effective mode area. The most effective way to mitigate nonlinearities (excluding self-focusing) is to enlarge the effective mode area by optimizing geometry designs and material choices of fiber structure. Unlike the passive power delivery fiber, this task is more challenge for active fiber, as doping-induced refractive index changing, and thermal stability will be issues. A straightforward design approach to maintain pure single-mode operation is to increase the core diameter, with the NA reducing correspondingly. However, the downside is the waveguide effect gets weaker, and consequently light is easier lost from the core when the fiber is bent. More works on fiber designs for addressing these challenges are related to photonic crystal fibers techniques. It is possible to make single mode operation in a multi-mode supported fiber, by building up preferentially amplify, or attenuate for specific mode, while the mixing or coupling between modes should be controlled to minimum. There have been works focu sed on using differential gain by selective RE doping across the core , and differential-bend-loss by controlled bending of the fiber. The leakage channel and chirally coupled core fibers are designed to selectively couple propagation mode to high loss mode. The high order mode but not the fundamental mode is coupled to leaky mode, which will substantially be attenuated. The multifilament core and multicore fiber arrange filaments or cores in a two-dimensional array. There are evanescent-field coupling among cores, and the overall structure can exhibit single-mode guidance with large mode area. Academic Objectives From the aspect of power generation, Investigation of advanced fiber for mitigating nonlinearity will be still the most critical issue in increasing the output power for cw fiber lasers. It has been estimated that the maximum single core output powers of the ytterbium doped fiber laser should be at several tens of kilowatts level based on present technique. However, single-mode operation is not indispensable for lots of high power lasers applications. The single or near single mode operation in the MM fiber which is developed by balancing the mode quality, the achievable power, and the damage threshold of the fiber, can offer possibilities to archive higher output power. In addition to that, as the emission wavelength of well developed thin disk laser is still covered by the Yb ions absorption band and is more close to the emission band of the Yb ion, the research on novel architecture using thin disk laser to tandem pump the special designed Yb doped fiber laser also offers the pote ntial to increase output power of fiber laser and develop novel fiber laser with useful function. The proposed research will focus on advanced fiber, especially for the evanescent-field coupled waveguides, also called multi-core fibers (MCF). The main aim is to design and realize novel types of active MCF for increasing the output power of fiber laser with good beam quality, and for suppressing the SBS effect. Besides that, Based on the advanced thin-disk laser, and the novel MCF fiber, the investigation on the novel laser architectures will also be performed. The Outline of the Project According to the above proposed objectives, the research work can be divided to two main phases. The first phase will be focused on fiber design and fabrication, and the expected deliverable is the novel active fiber with improved performance in nonlinearity mitigation and bending resistant. The other phase is about the novel fiber laser architecture, and investigation of the novel tandem pump configuration based on thin-disk laser will be performed. Mathematical Model and Design Strategy The main nonlinearities for cw operating fiber laser is SRS and SBS. Although both of them can be mitigated by the enlarged mode area, the SBS is still too strong for increasing the power of single frequency laser in the LMA fiber. The proposed research aimed to suppress the SBS in the LMA fiber for mitigating both SRS and SBS. According to the previous research, the SBS threshold can be expressed by : (1) The ÃŽÂ ±u is acoustic attenuation coefficient for the acoustic mode of order u, Aeff is the optical effective mode area, G(Ñ ´max) is the SBS effective gain coefficient at the peak frequency, K is the polarization factor. We can see form the equation. Beside the mode area, the SBS can be suppressed by increasing the acoustic loss, reducing the overlap integral, and the SBS effective gain coefficient. The is the normalized overlap integral of the electric and acoustic fields and it can be expressed as : (2) The E0 is the optical field associated with the fundamental mode, and à ?u the field of a longitudinal acoustic eigen-mode of order u. The overlap integral can be changed by modifying the fiber refractive index profile and acoustic velocity profile. The acoustic loss can be changed by glass composition design. As different dopants have different effects on optical and acoustic properties, it is possible to create suitable dopants profile in the core and cladding to reducing the overlap integral or increasing the acoustic loss. Table 1 is some common dopants used for making silica glass based fibers. The profile of the optical and acoustic field can be indicated by optical and acoustic refractive indices. Similar to the optical refractive index, acoustic refractive index is defined as na(r) = VL Silica /VL (r) , where VL(r) is the longitudinal acoustic velocity in the core, and VL Silica is the longitudinal acoustic velocity of pure silica glass. Table 1. Trend of optical and acoustic refractive index change of different dopants in silica GeO2 P2O3 TiO2 B2O3 F2 Al2O3 Optical refractive index à ¢Ã¢â‚¬  Ã¢â‚¬Ëœ à ¢Ã¢â‚¬  Ã¢â‚¬Ëœ à ¢Ã¢â‚¬  Ã¢â‚¬Ëœ à ¢Ã¢â‚¬  Ã¢â‚¬Å" à ¢Ã¢â‚¬  Ã¢â‚¬Å" à ¢Ã¢â‚¬  Ã¢â‚¬Ëœ Acoustic refractive index à ¢Ã¢â‚¬  Ã¢â‚¬Ëœ à ¢Ã¢â‚¬  Ã¢â‚¬Ëœ à ¢Ã¢â‚¬  Ã¢â‚¬Ëœ à ¢Ã¢â‚¬  Ã¢â‚¬Ëœ à ¢Ã¢â‚¬  Ã¢â‚¬Ëœ à ¢Ã¢â‚¬  Ã¢â‚¬Å" One straightforward approach to modify the loss for optical and acoustic field of a fiber structure is created a type of optical guiding and acoustic anti-guides with a dopant material(Fig 4 (a)), such as Al2O3, and it has been demonstrated in . The other approach is to reduce optical and acoustic field overlap, with different dopants in the core (Fig 4 (b)). The resultant optical and acoustic refractive index profiles of above approaches are shown below. (b) Fig. 4. Dopant designs for reducing the overlap of the optical and acoustic fields The strategies shown in fig 4 are based on single core fiber. There are quite a few research works on improving the effective mode field in single core fiber, and it is little room to enlarge the effective mode field areas further without detrimental effect in single core fiber LMA. Recently, multicore fiber based LMA has been investigated as passive delivery fiber , and as active fiber in the novel laser architecture. The supported optical mode field of MCF can be designed by core size and core interval; the profile of the acoustic and optical field can be modified by the distribution of dopants and doping area size; and the loss of the optical and acoustic can be controlled by doping material. Thus, it is worth investigating a novel active MCF supporting a few modes or only single supermode with the reduced overlap between the acoustic and optical field. Optical Index Al Yb Ge F/B Acoustic Index Fig 5 the schematic of the proposed 19 core double cladding fiber A fiber design strategy to suppress the SBS is shown in Fig 5. An optical guide while acts as an acoustic anti-guide in the effective optical field areas of MCF will be fabricated by manipulating dopants in core and cladding, for example as shown in fig 5, by choosing Al2O3 in core and GeO2 in cladding. Because the fields of optical and acoustic are separated, the interaction between the optical and acoustic waves is weaker. Furthermore, the MCF will be designed to support a few modes or only one supermode, that benefits for manipulating refraction index to increase threshold of the SBS in the single mode MCF, as the à ¢Ã‹â€ Ã¢â‚¬  n=neffà ¢Ã‹â€ nclad of single mode MCF is larger than single mode single core fiber(SMF), for example, the index difference à ¢Ã‹â€ Ã¢â‚¬  n=neffà ¢Ã‹â€ nclad is 3.69ÃÆ'—10à ¢Ã‹â€ 4 in the case of the 19-core fiber reported in and only 1.60ÃÆ'—10à ¢Ã‹â€ 4 for the SMF, providing more room of à ¢Ã‹â€ Ã¢â‚¬  n for manipulating dopants. Finally, the reference value of parameters such as the diameter of each core, the core interval, and the doped areas of each core, will be archived by numerical calculation. Numerical Calculation The optical field in the waveguide can be solved by numerical calculation the Maxwell equations. Like the optical field, by numerical calculating the nonlinear acoustic equation, the acoustic field can be obtained. After that the SBS threshold can be calculated with equation (1), (2). From the nonlinear acoustic equation, we can obtain the equation that determines the longitudinal acoustic eigen-modes. The acoustic modes that contribute to the SBS associated with the optical fundamental mode have constant azimuth. Neglecting the damping factor, the radial distribution of such a mode can be expressed as: (3) The ÃŽÂ ©u is the acoustic frequency and the ÃŽÂ ²u is the propagation constant of the acoustic mode, VL(r) is the longitudinal acoustic velocity profile across the fiber. The wave equation for optical field in waveguide is derived from the general Maxwell and can be written as: (4) The EO is the optical field, ko=2p/l is the wave number of the optical field, and no(r) is the refraction index profile across the fiber. The optical mode is efficiently backscattered by the acoustic mode when the phase-match condition, ÃŽÂ ² = 2ÃŽÂ ²u, is fulfilled, where ÃŽÂ ² is the propagation constant of the optical field. The ÃŽÂ ² is determined by the optical wavelength ÃŽÂ », the effective refractive index no,eff, and it can be expressed as: ÃŽÂ ² =kono,eff=2pno,eff/l. Determined by the structure, the acoustic field in the proposed 19 core fiber is confined in the inter cladding, and the acoustic index can affect the confining effect. As the position of inter cladding is fixed, once the doping concentration is chosen, the acoustic field will be determined. The optical field in the MCF is determined by both the doping concentration and the geometry structure of the MCF. It is the geometry structure of the MCF provides the extra room to design the optical field with desired mode. The field of a longitudinal acoustic (à ?u) can be numerical calculated with finite-element method. beside the finite-element method, previous research has indicated the à ?u can be solved by utilizing the solver for optical scalar wave equation after defining a few new terms for acoustic wave. to numerical solve the equations (4), as numerical calculation by the finite element method is still valid when strong coupling exists between the different cores, the mode structure of the optical filed in the MCF is also calculated by finite-element method based on commercial available software such as Fimmwave or Comsol-Multiphysics. After knowing the à ?u and the EO, the can be calculated by taking the à ?u and E0 into equation (2). Finally, taking the into equation (1), the Pth of the designed fiber can be obtained. The theoretical M2 propagation factor can be computed with the method in. For a doping state, different Pth value and mode structures can be achieved for different geometry parameter, such as single core diameter and core interval. Optimizing the geometry parameter is necessary to get the high Pth value with good mode structures. Finally, repeatedly implementing above step for different doping condition, a series of optimized reference parameters can be obtained. The home institute IFSW has equipped the fiber manufacturing facility consisting of a modified chemical vapor deposition (MCVD) preform production lathe and the new commissioned drawing tower. The prototype of the proposed double-clad MFC fiber will be produced in the IFSW by the stack and draw technique. Investigation on the Laser Architectures The mode field mismatch and high operation power set the obstacles on employing the state of art fiber communication components in the high power laser architecture. Beside that some of critical components for high laser, such Bragg gratings in the LMA cores, large mode area pump coupler or combiner for high power diode are still in the initial stages. Above aspects cause the architecture for the exited high power laser is limited comparing with well developed communication band fiber laser. Most of the previous research on increasing the output power focused on developing the LMA fiber. As the difficulty of increasing the output power by enlarging the mode field is increasing continuously, it is time to consider improve the laser output from other aspect. The high brightness power scalable thin disk laser acting as the in-band pumping source can generate less quantum defect heat than 9ÃÆ'—ÃÆ'—nm laser diode, providing the potential to developing novel or improving existed laser structure by using components which are thermal damage or degradation sensitive. Thus there are rooms to increase the output power or improve the efficiency by developing the laser architecture with thin disk laser and special designed high power components. One of proposed architecture improvements is to replace the butt-coupled HR-mirror in the existed laser with the Bragg grating in the core of the double cladding fiber. Fig 6 (a) the butt-coupling mirror based laser architecture Fig 6 (b) the FBG based laser architecture FBG1,2 reflectors for the laser radiation; FBG3 reflectors for the pump light; The reflection rate of the FBG1 is around 99%, that of FBG2is around 50%. For the butt-coupled mirror based laser architecture (Fig 6 (a)), as the butt-coupled mirror will reflect both the pump light and the laser radiation on a very small area, the energy densities will be extremely high in core and cladding near the conjunct point. To withstand such high power densities, special material substrate such as the sapphire is needed to remove the heat very quickly. Even though, the core power density is still close to the damage threshold of the mirror coating. Furthermore, as the pump wavelength is closed to the laser radiation wavelength, to fabricate the dichroic mirror will be rather difficult. Although the Bragg grating inside the fiber core still has the problem of thermal damage, the damage threshold of FBG will be higher than mirror face. Considerable power increasing is expected for replaying mirror with the Bragg grating. From the aspect of fabrication, the wavelength of the Bragg grating is determined by the mask period and the refraction index of the fiber core, it will be easy to fabricate two FBG with spectrum interval larger than 4nm, which is enough to separate the in band pump light and laser radiation. Finally the FBG also can provide the facility to control the laser wavelength, and the laser output wavelength will be determined by the corresponded reflector. In fig 6 they are FBG1,2. Fig 7 the proposed hybrid laser architecture DMCF: doped multicore double cladding fiber, SMF: single-mode fiber, PMSF: polarization maintained single mode fiber ISO1: polarization dependent optical isolator, Amp: amplifier, DM: dichroic mirror, BS: beam splitter,Li (i = [1; 5]): plus lenses, FBG1: fiber Bragg grating for laser radiation, FBG2: fiber Bragg grating for pump light, PZT: Piezoelectric Ceramics Limited by components, many well developed communication fiber laser techniques such as wavelength tuning and polarization stabilizing cannot be projected to high power fiber laser area directly. A promising method to solve the problem is to develop hybrid architecture which employs a low power single mode fiber feedback loop to control the high power laser. By applying the advanced communication laser techniques in the single mode feedback loop, the high power fiber laser with wavelength tuning and polarization stabilizing can be realized. The proposed hybrid laser architecture with wavelength tuning and polarization stabilizing is shown in fig 7. The thin disk emitted pump light is coupled to the double cladding fiber with a dichroic mirror and a plus lens. The FBG in pump wavelength is employed in the far end of the active fiber. A small part of the emitted beam is reflected and coupled to the feedback loop whereas the most of power is coupled out from the laser cavity. The lens set (L4 to L6) constitutes a free-space imaging system for projecting the far field of the DMCF onto the input face of the SMF. Polarization independent optical isolators and circulator in the feedback loop determined the light traveling direction and eliminated the unwanted reflected light. Furthermore, the polarization independent optical isolator shapes the light to single polarization state, which will be persevered in the feedback loop by polarization maintained fiber. The FBG1 is fixed in a stretch preloaded piezoelectric ceramics, and the reflected wavelength can be tuned slightly by driving the PZT with Bi-directional signal. After passing th e feed pack fiber, the DMCF will amplify the seed laser radiation, and consequently power will be scaled and the polarization can be preserved.

Personal Financial Management Essay

1. You need to hire a receptionist that will be handling cash. What steps would you take to make sure you hire the right person? Inquire about previous cash handling experience, ask about their personal financial management, how they handle their personal finances. 2. Why should you teach your employees the importance of personal financial management? What are some creative ways of doing this? How employees handle their income reflects their work performance, if someone is having financial issues it will most likely cause them to be stressed at the work place. It is important to teach employees how to handle their finances so the overall performance of the company is not affected. Some ways to do this is by having workshops, company meetings, games, or a company lunch. Any setting where a financial manger could come in and answer any questions an employee might have as to how to manage their finances better. 3. What specific steps can you take to improve your spending habits? Some ways I could improve my spending habits would be to assist my want versus need. I can admit that at times I do unnecessary spending. I should make a budget of how much I spend and how much I earn and try to be fugal in my spending habits.

Loss and Grief

What is loss? What is grief? Loss is most often equated to death but generally, â€Å"loss occurs when an event is perceived to be negative by individuals involved, and it results in long-term changes in one's social situations, relationships, or way of viewing the world and oneself† (Marriage and Family Encyclopedia 2008). One tends to experience loss in one’s lifetime. Children usually experience loss through a death of a pet or a parent. Adults likewise experience loss through death of a spouse or because of divorce; they may also experience job or health losses.When we value something or someone that we lost, we experience grief. â€Å"Grief is the psyche’s natural healing response when faced with change and loss† (PsychCentral 2008). This suggests that grief is a normal and natural experience to a person who has experienced personal loss. Furthermore, it is said to be a â€Å"process, not an event† (PsychCentral 2008) which means that grief sho uld be allowed and given time to completely take place. Strayhorn enumerates the characteristics of grief (PsychCentral 2008). First, he says that pain is a natural part of grieving.One may choose to repress or ignore the pain but he says that further losses in life can always trigger it and eventually, the hurt only doubles. Second, he maintains that ‘grieving is a highly individualized process’ (PsychCentral 2008). This demonstrates how different each person is while in grief. Though grief is said to be a universal and a natural occurrence, the way one person grieves differs from another. Furthermore, being aware of the five stages of grief: â€Å"shock, anger, bargaining, depression, acceptance† (PsychCentral 2008) helps one to cope with grief.Lastly, Strayhom states that â€Å"grief has no timetable† (PsychCentral 2008). Grief therefore should be allowed to take its own course. However, each individual in the process of grieving should also do activiti es to help them heal. Constantly sharing ones deepest sentiments to a trusted friend is always beneficial to a person in grief. There have been known grief responses, â€Å"such as a yearning for the lost person or state of affairs, a need to think repeatedly about past events, a sense of guilt, or even thoughts of suicide.(Death Reference 2008)† According to the Death Reference website (2008), Terry Martin and Kenneth Doka formulated 3 basic patterns of grief. First is the Intuitive Pattern, where the griever freely manifests his/her feelings. He/She can display intense emotions such as outbursts and crying. Any means to allow the griever to vent out his/her emotions is beneficial for coping. Second is the Instrumental Pattern where the griever would recall memories of the dead person and doing something in relation to those thoughts.An example cited by Martin and Doka (1999) where a man who has lost his daughter in a vehicular accident fixed the fence which his daughter has ruined during the accident. He said that it was the only thing he could repair. Third is the Dissonant Pattern. â€Å"Dissonant grievers are those who experience grief in one pattern but who are inhibited from finding compatible ways to express or adapt to grief that are compatible with their experience† (Death Reference 2008). For instance, when a man loses his wife, he can feel the urge to cry with his daughters and to show weakness.However, he chooses to keep it, as it is inappropriate for a man to do so. Women who lose spouses can experience the same situation, when she inhibits emotions and puts up a strong stance to protect her children. Loss and Grief on Different Perspectives There have been various studies about grief and prove that its characteristics are individualized and unique. On the one hand, children, grieve differently from adults (PsychCentral 2008). Young kids often think that the person who died will soon come back as seen in cartoon shows.Meanwhile, the re are signs which tell whether the child is experiencing significant grief. He/She tends to become immature for his/her age and there is also a considerable decrease in school performance. When these are present, Cohen advises the child be seen by a child psychologist (PsychCentral 2008). On the other hand, men and women also have distinct characteristics of grief. In an article written by Karen Carney in PsychCentral (2008), she enumerates the key points on how men grieve basing from Tom Golden’s book entitled ‘Swallowed by a Snake: The Gift of the Masculine Side of Healing’ (1997).Golden mentions that counselors tend to use approaches similar to what they use towards women, which was later on found to be ineffective to men. Men usually cope by busying themselves with any activity that would either use the mind or the body (PsychCentral 2008). Moreover, men try to go on living their lives as normal as possible like going on their usual routine. In contrast, wom en are attached to their feelings. They have the tendency to recall memories of the loved one who died (Linda-Angel 2005).It is significant to note that there are differences between the characteristics of the male and female human brain, which can be a cause of the distinction on how each sex grieves (PsychCentral 2008). In a study by Buchebner-Ferstl (2002), she mentions the differences between how a woman and a man deal with loss of a loved one (death). She said that women have broader social networks than men, and that women are often the source of social support between the couple. Being the case, she says that some experts would conclude that because of this, women cope better with loss.Moreover, â€Å"women are said to have a more emotionally-oriented behaviour, and men are said to be more problem-oriented† (Buchebner-Ferstl 2002). This means that women are more geared than men to grieve and share their emotions with other people. In addition to this, she mentions that research shows that women are said to have a â€Å"stronger sense of survivability †¦ [and] men are biologically more susceptible to the negative effects of stressors† (Buchebner-Ferstl 2002). This demonstrates that women are more apt to survive loss than men.Also, it was mentioned in the Death Reference website (2007) that men were socially conditioned to hide their emotions. In contrast, women can openly share their feelings to other people, allowing grief to take its course. Further, Louis LeGrand states that the gender difference â€Å"does not mean that men are not grieving; it does indicate that they may not accomplish the task as successfully as women† (LeGrand 1986:31). In a research conducted by Martin and Doka (1999), the differences between how women and men grieve were tackled. Their research showed the following:†¢ Upon the death of a spouse, the widower would usually engage in activities such as working or gym activities and are likely to resor t to alcohol. Conversely, widows spend time with friends and family for emotional support. †¢ Similarly, for those parents who have lost a child, the mothers tend to show emotions than the father. †¢ For those middle-aged children who lost a parent, the sons were more likely to engage in busy activities to deal with the loss while daughters show grief. †¢ Basing on the older generation, there are only slight differences on manifesting grief.†¢ â€Å"Differences in gender are also affected by other variables such as social class, generational differences, and cultural differences† (Death Reference 2008). †¢ The paper suggests that studies show varying results in terms of which gender copes with grief more effectively. The study of grief on the basis of gender is remarkable however Doka claims that the â€Å"[grief] pattern is not determined by gender† (Death Reference 2008) alone but is affected by other factors as well. Cultures differ in socia l norms and practices.There are societies where the sight of a man crying in grief is as acceptable as when a woman does (Death Reference 2008). Additionally, cultures differ in valuing relationships and attachment towards people and things, thus they also differ in grief experiences. Models of Loss and Grief There have been a number of loss and grief models that is based on the notion that every person in grief goes more or less in ‘the same sequence of stages in the recovery from grief, and at relatively the same speed’(Slap-Shelton 2008). Particularly on death, Kubler-Ross has formulated a model composed of 5 stages, as follows:1. ‘Denial and Isolation’ – The person who experienced death cannot accept that he/she actually lost a loved one. In severe cases, the person completely denies that death took place (Slap-Shelton 2008). 2. ‘Anger’- Here the person expresses anger towards others, and towards God, questioning Him why the loss had to happen to him/her (Slap-Shelton 2008). 3. ‘Bargaining’ – This is when one bargains and tries to compromise with God. 4. ‘Depression’ – As the person realizes and acknowledges the loss, he/she now experiences depression and deep sadness.5. ‘Acceptance’- The bereaved now accepts the reality of loss and is able to project a new life ahead. Based on a number of literatures on grief, Kubler-Ross’s model has become one of the most known and familiar. This model appears to define the stages of dying, phases of grief and is applicable not only to death but in other losses such as divorce or a break up. In the University of Kentucky website, Kastenbaum criticizes Kubler-Ross’s model, saying that these are not supposed to be stages as they do not happen chronologically (1998).In addition, he says that all these five stages are not necessarily undergone by a person dying or grieving. He further maintains that grief is uniqu e to every individual (University of Kentucky 1998). This demonstrates that these stages limit the process of grieving which is supposed to be individualized. Following this, various theoretical models on loss and grief were formulated. Charles Corr, specifically believed in the individuality of coping with death (University of Kentucky 1998). People differ in values therefore they also differ in need and coping mechanism for the same experience of loss.Meanwhile, Worden, Leick & Davidsen-Nielson (1991) proposed four means to understand loss and help accept its reality. First, one should recognize the fact that someone died or left for good. Second, one should not suppress the emotions but let them take their course. According to Slap-Shelton, (1998) among the intense emotions that one can feel during loss include â€Å"sadness, despair, anger, guilt, fear, loneliness, shame, jealousy. † Furthermore, to allow feeling these and letting these manifest will help in recovering ov er the loss.Third, it is advisable to let in something new in your life. For instance, one can learn a new skill or find a new set of friends. Through the process the person who experienced loss can grow despite the circumstance. Lastly, one ought to â€Å"reinvest emotional energy into the present† (Slap-Shelton 1998). This means that the bereaved person should focus on what is ahead and what he/she can do to live this new life without the person who died. Some, for example, do activities that commemorate and celebrate the goodness of the dead person.Furthermore, grief can be more understood in two other perspectives: psychoanalytic and attachment perspectives Basing from psychoanalysis, grief stems out of the griever’s uncertainty of where his/her relationship stands, now that the partner died. At the same time, â€Å"the psychological function of grief is to free the individual of the tie to the deceased and allow him or her to achieve a gradual detachment by means of a process of grief work† (Death Reference 2008). Many counselors and therapists have been influenced by this however such theory has also been criticized.On the other hand, Bowlby’s theory was based on the biological aspects of grieving. He maintains â€Å"that the biological function of grief was to regain proximity to the attachment figure, separation from which had caused anxiety† (Death Reference 2008). This means that when humans are separated from a figure whom or which they had attachment to, this results to reactions of grief. Conclusion According to the Marriage and Family Encyclopedia (2008), more recent models on loss and grief are now focused on â€Å"identifying symptoms [rather than] the process of grieving† (Marriage and Family Encyclopedia 2008).Stroebe and Schut (1990) formulated the Dual Process Model of Coping. Humans cope with grief with a combination of both â€Å"loss orientation† and â€Å"restoration orientation†. Loss orientation is allowing grief to take place for instance crying and reaching out to others while restoration orientation is â€Å"adjusting to the many changes triggered by loss† by engaging in new activities. Such dual model recognizes grief as a â€Å"dynamic and fluctuating process, labeled ‘oscillation,’ that incorporates confrontation and avoidance of different components at different times, and includes both positive and negative reappraisals† (Death Reference 2008).For instance, a man who lost his wife learns how to paint and takes pleasure in the activity (restoration orientation). However in the process, he is asked to paint a memorable place and thus reminded of the wife who has died and feels sad about it (loss orientation). Basing from the literature reviewed, grief can be described as universal since all humans at one point in their lives experience grief. Grief is natural since it is said to be an inevitable response to loss. However, th ere has not been an encompassing theory that can gauge grief; perhaps due to its vastness and complexity.Further studies and research, particularly on the biological perspective, how grief starts and where it ends, will allow a deeper understanding of human grief. List of References Buchebner-Ferstl, S 2002, Gender-specific differences in coping with bereavement, Osterreichisches Institut fur Familienforschung, Austria, viewed 30 Maarch 2008, . Carney, K 2006, How men grieve, 4 November, viewed 1 April 2008, . Cohen, H 2007, Children and grief, 4 June, viewed 1 April 2008 Coping With Loss 2008. Marriage and Family Encyclopedia viewed 28 March 2008 . Encyclopedia of Death and Dying. 2008. [online]. [accessed 29-31 March 2008]. Available from World Wide Web: . LeGrand, L. 1986 Coping with separation and loss as a young adult. Springfield, IL: Charles C.Thomas. Martin, T. & Doka, J. 1999. Men don't cry, women do: Transcending gender stereotypes of grief. Philadelphia: Taylor & Francis . Rosenblatt, P. , Walsh, R. & Jackson, D. 1976. Grief and mourning in cross-cultural perspective. Washington, DC: HRAF Press. Schwab, R n. d. ,Gender, Encyclopedia of Death and Dying, viewed 29 March 2008, . Slap-Shelton, S 1991, The phases and tasks of grief work, Self Help Magazine, viewed 31 March 2008, .Strayhorn, D 2008, Surviving a life crisis, 21 January, Psych Central, viewed 1 April 2008,. Stroebe, M. , & Schut, H. , 1990. The Dual Process Model of Coping with Bereavement: Rationale and Description. Death Studies 23, p. 197–224. Stroebe, M, Stroebe, W & Schut, H, Theories on grief, viewed 29 March 2008, . Women, men & grief 2005, Child Bereavement Trust, viewed 31 M arch 2008, .

The Meaning of Tenir in French and How to Use the Verb

Tenir is an irregular verb ending in -ir and usually means to hold or to keep. Tenir has a number of other meanings, including some which depend on the preposition that follows. Its used in a number of French expressions. Meanings of Tenir Tenir usually means to hold or to keep: Quest-ce quil tient à   la main?  Translation: What is he holding in his hand?Je dois tenir les enfants par la main. Translation: I need to hold the kids hands.Tenez les yeux fermà ©s. Translation: Keep your eyes closed.Il faut tenir cette affiche en place. Translation: You need to hold this poster in place. Additional Meanings To have/keep under control: Vous tenez bien votre classe.Translation: You have your class under control. To run/manage (a business): Qui tient le magasin?Translation: Whos running the store? To organize (an event): Le comità © tient une sà ©ance chaque mois.Translation: The committee holds a meeting every month. To handle, be able to accept: Elle ne tient pas lalcool. (informal)Translation: She cant hold her liquor. To keep: Je tiens toujours mes promesses.I always keep my promises. To take up, fulfill: Cette table tient trop de place.Translation: This table takes up too much room Tenir à   Tenir à   may be followed by a noun, an infinitive, or a clause. When followed by a noun, it means either to value, care about, be attached to or to be due to, stem from: Je ne tiens pas à   son opinion. Translation: I dont care about his opinion.À quoi tient son succà ¨s? Translation: What is the secret of his success? When followed by an infinitive or ce que subjunctive, tenir à   means to be anxious/eager: Je tiens à   vous remercier. Translation: Im eager to thank you.Il tient à   ce que tu sois à   laise. Translation: Hes anxious for you to feel comfortable. Tenir can also be used to mean to depend on - most commonly with ne___ quà  : Cela ne tient quà   toi de choisir. Translation: Its up to you to choose. The choice depends (only) on you.Cela ne tient pas quà   moi. Translation: It doesnt depend on me alone. Tenir de Tenir de means to take after/resemble, to have to do with: Elle tient de sa mà ¨re. Translation: She takes after her mother.Cela tient du miracle. Translation: That seems like a miracle, Theres something miraculous about that. Se Tenir Reflexively, tenir means to hold (oneself), to be in a position, or to behave: Pourquoi se tient-il la jambe? Translation: Why is he holding his leg?Je me tenais par une main. Translation: I held myself (up) with one hand.Tu dois te tenir debout. Translation: You have to stand up.Nous nous tenons prà ªts à   partir. Translation: Were prepared to leave.Elle se tient bien. Translation: Shes well-behaved.Tiens-toi tranquille! Translation: Behave yourself! Be quiet! Se tenir can also be used intransitively with many of the meanings in the first section (to hold a meeting, to be connected, etc) Present Tense Conjugations je tienstu  tiensil tientnous  tenonsvous  tenezï » ¿ils  tiennent