Hukum singkatan SAW
Can We Write “SAWS” in Place of
“Sallallaahu ‘Alayhe wa Sallam“? 
In the Name of Allaah, may the Salaah and Salaam of Allaah be upon His Final Messenger, to proceed:
Muslims are obliged to send Allaah’s Salaah  and Salaam  upon Muhammad (sallallaahu ‘alayhe wa sallam) when his name is mentioned. Allaah has commanded us :
( Verily Allaah and His Angels send salaah on the Prophet. O you who believe! Invoke salaah upon him, as well as a complete salaam! )
And the Messenger of Allaah (sallallaahu ‘alayhe wa sallam) said:
“For each time someone invokes salaah upon me, Allaah writes for him ten good rewards because of it.” 
And the Prophet (sallallaahu ‘alayhe wa sallam) had described the one who does not send salaah upon him when he is mentioned as “the stingiest of people.”  And he exclaimed “Aameen!” to Jibreel’s supplication, “May Allaah repel the one who hears mention of you and does not invoke any salaah upon you!” 
So here is the issue that needs to be clarified: Many people use the abbreviation “SAWS” or “PBUH” to fulfill this obligation in their writing. Is this something that fulfills the obligation of sending the salaah and salaam on the Messenger? Let us look now to some of the statements of the scholars regarding this practice.
The Committee of Major Scholars in Saudi Arabia headed by ‘Abdul-‘Azeez ibn ‘Abdillaah ibn Baaz issued the following verdict when asked about the validity of abbreviating the salaah on the Prophet (sallallaahu ‘alayhe wa sallam): “The Sunnah is to write the entire phrase “sallallaahu ‘alayhe wa sallam,” since it is a kind of supplication, and supplication is worship, (in one’s writing) just as it is in one’s speech. So to abbreviate it using the letter SAAD or the word SAAD-LAAM-‘AYN-MEEM is not a supplication nor it is worship, whether it occurs in speech or writing. For this reason, this abbreviation was not used by the the first three generations, those that the Prophet (sallallaahu ‘alayhe wa sallam) testified to their goodness.” 
“SAAD” and “SAAD-LAAM-‘AYN-MEEM” are often used in some ‘Arabic books. The English equivalents of these abbreviations would be: SAW, SAWS, SAAWS, PBUH, and the likes.
Al-Fayrooza-abaadee said, “It is not appropriate to use symbols or abbreviations to refer to salaah and salaam, as some of the lazy ones do, as well as some ignorant people and even some students of knowledge – they write ‘SAAD-LAAM-‘AYN-MEEM’ instead of writing ‘sallallaahu ‘alayhe wa sallam.'” 
Ahmad Shaakir said, “It is the absurd tradition of some of the later generations that they abbreviate the writing of ‘sallallaahu ‘alayhe wa sallam.'” 
Wasee Allaah ‘Abbaas said, “It is not permissible to abbreviate the salaams in general in one’s writing, just as it is not permissible to abbreviate the salaah and salaam on the Prophet (sallallaahu ‘alayhe wa sallam). It is also not permissible to abbreviate either of these in one’s speech.” 
And Allaah knows best. May the most perfect and complete salaah and salaam be upon our beloved Messenger, and upon his noble family and companions.
This article was taken from BAKKAHnet (www.bakkah.net)
 written by Abul-‘Abbaas
 Sending salaah on the Prophet (sallallaahu ‘alayhe wa sallam) means that one invokes Allaah to praise him and mention his high status to the angels. See Jalaa’ Al-Afhaam (p.253) of Ibn Al-Qayyim, Fat-hul-Baaree (11/179-197) of Ibn Hajr, or Ibn Katheer’s tafseer to verse 33:56.
 salaam: security
 the meaning of Soorah Al-Ahzaab (33):56
 an authentic hadeeth collected by Ibn Hibbaan in his Saheeh (#906, 3/187) on the authority of Aboo Hurayrah (may Allaah be pleased with him). Al-Albaanee declared it to be saheeh in Silsilatul-Ahaadeeth As-Saheehah (#3359, 7/1080).
 from a hasan hadeeth collected by Ibn Abee ‘Aasim in As-Salaah ‘Alan-Nabee (p.30-31) on the authority of Aboo Tharr (may Allaah be pleased with him). Hamdee As-Salafee called it hasan in his checking of the book.
 from an authentic hadeeth collected by At-Tabaraanee in Al-Mu’jam Al-Kabeer on the authority of Jaabir ibn Samurah (may Allaah be pleased with him). Al-Albaanee authenticated it in his checking of Al-Munthiree’s At-Targheeb wat-Tarheeb (#1677, 2/298).
 Fatwaawaa Al-Lajnatid-Daa’imah #18770 (12/208-209)
 From his book As-Salaatu wal-Bushr, as quoted in Mu’jam Al-Manaahee Al-Laf-thiyyah (p.351)
 the Musnad of Imaam Ahmad (#5088, 9/105)
 from a handwritten answer provided by the shaykh, file no. AAWA004, dated 1423/6/24