问题 问答题 简答题

阐述光纤通信系统对光源的要求。

答案

参考答案:

(1)光源的发射波长应该与光纤的低损耗窗口一致,即为850nm、1310nm和1550nm的三个低损耗窗口;

(2)光源有足够高的、稳定的输出光功率,以满足系统中继距离的要求,一般为数十微瓦至数微瓦为宜;

(3)光源的光谱线宽要窄,即单色性好,以减小光纤色散对信号传输质量的影响;

(4)调制方法简单,且要响应速度快,以满足高速率传输的需要;

(5)电光转换效率要高;

(6)能够在室温下连续工作;

(7)体积小,重量轻,寿命长,工作稳定可靠。

填空题
阅读理解

Do you want to love what you do for a living? Follow your passion. This piece of advice provides the foundation for modern thinking on career satisfaction. But this can be a problem.

I've spent the past several years researching and writing about the different strategies we use to seek happiness in our work. It became clear early in the process that the suggestion to “follow your passion” was flawed (有缺陷), for it lacks scientific evidence. However, it doesn't mean you should abandon the goal of feeling passionate about your work. The reality emphasizes that things are quite complicated.

Passion is earned. Different people are looking for different things in their work, but generally, people with satisfying careers enjoy some combination of the following features: autonomy,respect, competence, creativity, and a sense of impact. In other words,if you want to feel passionate about your livelihood,don't seek the perfect job,but seek to get more of these features in the job you already have.

Passion is elusive (难捉摸的). Many people develop the rare and valuable skills leading to passion, but still end up unhappy in their work. The problem is that the features leading you to love your work are more likely to be useful to you than your organization. As you become increasingly “valuable”,for example, your boss might push you toward traditional promotions that come with more pay and more responsibility, as this is what is most useful to your company. However, you might find more passion by applying your value to gain autonomy in your schedule or project selection.

Passion is dangerous. I've watched too many of my peers fall into anxiety and chronic(慢性的) job-hopping (跳槽) due to the “follow your passion” advice. The issue is expectations. If you believe we all have a pre-existing passion, and that matching it to a job will lead to instant workplace happiness, reality will always pale in comparison.

Work is hard. Not every day is fun. If you're seeking a dream job, you'll end up frustrated, again and again. Don't set out to discover passion. Instead, set out to develop it. This path might be longer and more complicated than what most cheerful career guides might advocate, but it's a path much more likely to lead you somewhere worth going.

小题1:People satisfied with their careers are _______.

A.autonomous and passionate

B.creative and passionate

C.respectable and sensitive

D.creative and competent小题2:What is the author's advice on achieving career satisfaction?

A.Figuring out early what one will do in the future.

B.Matching the pre-existing passion to one's work.

C.Developing passion for what one is doing.

D.Discovering skills that lead to interesting careers.小题3: The underlined sentence in Para. 5 probably means that _______.

A.it is not easy to match our passion with our jobs

B.we shouldn't think everyone has a pre-existing passion

C.workplace happiness does not require a pre-existing passion

D.high expectations of passion in jobs bring disappointment小题4:What's the author's attitude towards the advice of “following your passion”?

A.Disapproving.

B.Supportive.

C.Cautious.

D.Unclear.